Question: A 7-week-old boy presents to the pediatrician for vomiting. Three weeks ago, the patient began vomiting after meals. The vomitus appears to be normal stomach contents without streaks of red or green. His parents have already tried repositioning him during mealtimes and switching his formula to eliminate cow’s milk and soy. Despite these adjustments, the vomiting has become more frequent and forceful. The patient is voiding about 4 times per day and his urine appears dark yellow. He has fallen 1 standard deviation off of the growth curve. The patient's mother reports that the pregnancy was uncomplicated other than an episode of sinusitis in the 3rd trimester, for which she was treated with azithromycin. The patient's temperature is 98.7°F (37.1°C), blood pressure is 58/41 mmHg, pulse is 166/min, and respirations are 16/min. On physical exam, the patient looks small for his age. His abdomen is soft, non-tender, and non-distended. Which of the following is the most appropriate next step in management?

Answer: Intravenous hydration

Explanation:
This patient presents with nonbilious, forceful vomiting, poor weight gain, signs of dehydration, and a history of exposure to azithromycin, which suggests a diagnosis of pyloric stenosis. The most appropriate next step in management is intravenous hydration.

Pyloric stenosis classically presents in a male infant between 4 to 6 weeks of age with nonbilious, projectile vomiting after meals. Risk factors for pyloric stenosis include bottle feeding and exposure to macrolide antibiotics in the patient or mother. Protracted vomiting frequently leads to hypochloremic, hypokalemic metabolic alkalosis. Patients should be resuscitated with intravenous hydration and evaluated for electrolyte abnormalities that require repletion. After a patient is adequately resuscitated, patients can undergo an ultrasound to confirm the diagnosis and then be treated surgically for definitive therapy.

Adams and Stanton review the evidence regarding the diagnosis and treatment of neonatal bowel obstruction. They discuss how malrotation, jejunoileal atresia, duodenal atresia, and colonic atresia are common causes of this finding. They recommend surgical management of these conditions.

Incorrect Answers:
Answer A: Abdominal ultrasound is the test of choice to diagnose pyloric stenosis, but evaluation for electrolyte derangements and subsequent intravenous hydration and electrolyte repletion should be initiated first in this patient with signs of dehydration and malnutrition. Further evaluation is reserved after a patient is adequately resuscitated.

Answer B: MRI of the head would be appropriate if this patient had additional signs of a mass in the head, such as neurological changes or worsening of the vomiting in the morning. In the absence of these signs and the presence of a mass in the epigastrium, this patient is more likely to have pyloric stenosis.

Answer C: Pyloromyotomy is the definitive management of pyloric stenosis, but this patient should undergo fluid replacement and have any electrolyte derangements detected and managed before undergoing surgery. Surgical intervention can carry significant risks if patients are not adequately resuscitated.

Answer E: Thickening feeds are one of the techniques used to manage gastroesophageal reflux. In the setting of this patient’s epigastric mass and clinical picture, pyloric stenosis is the more likely etiology of his vomiting. Reflex presents with non-projectile vomiting that is dependent on position.

Bullet Summary:
Patients with pyloric stenosis should first undergo intravenous rehydration and electrolyte repletion, as protracted vomiting may lead to severe hypochloremic, hypokalemic metabolic alkalosis.


Question: A 3-month-old boy presents to the pediatrician with his mother for a well-child visit. The patient drinks 4 ounces of cow’s milk formula every 3 hours. He usually stools 1 time per day and urinates up to 6 times per day. He regurgitates a moderate amount of formula through his nose and mouth after most feeds. He does not seem interested in additional feeding after these episodes of regurgitation and he has become progressively more irritable around meal times. The patient is starting to refuse some feeds. His mother denies seeing blood or streaks of red in his stool and she denies any family history of food allergies or dermatological problems. The patient’s weight was in the 62nd percentile 4 weeks ago and he is now in the 48th percentile. His height and head circumference have followed similar trends. His temperature is 98.2°F (36.8°C), blood pressure is 72/47 mmHg, pulse is 125/min, and respirations are 27/min. On physical exam, the patient smiles reciprocally and can lift his head and chest when in the prone position. His abdomen is soft, non-tender, and non-distended. Which of the following is the most appropriate next step in management?

Counsel on positioning and thickening feeds

Answer: Counsel on positioning and thickening feeds

Explanation:
This patient presents with frequent regurgitation after feeding, worsening irritability, feeding aversion, and poor weight gain, which is concerning for gastroesophageal reflux disease (GERD). The most appropriate next step in management is counseling on proper positioning and thickening feeds.

Infants with GERD may present with regurgitation or vomiting after feeding, significant irritability, feeding aversion, and poor weight gain or failure to thrive. Symptoms can usually be managed with lifestyle changes including more frequent, thicker, and lower volume feeds and positioning the patient upright during and after feeding. If symptoms continue, patients should undergo a trial of a dairy-free diet to address possible underlying food protein intolerance. Pharmacotherapy with proton pump inhibitors (PPI) is appropriate for patients with persistent symptoms despite these changes, although PPIs can increase the risk of pneumonia and infection with C. difficile.

Chabra and Peeples review the evidence regarding the treatment of neonatal GERD. They discuss how alterations in the infant's environment and feeding pattern are effective in most cases. They recommend proton pump inhibitors if conservative treatments are not effective.

Incorrect Answers:
Answer B: Initiating medical therapy with a proton pump inhibitor is appropriate for patients who have already failed lifestyle changes, including positioning therapy, adjusting feeding patterns, and eliminating cow’s milk and soy from the diet.

Answer C: Obtaining an abdominal ultrasound would help diagnose pyloric stenosis. Patients with pyloric stenosis typically present at a younger age (between 3 and 6 weeks of life) with non-bilious, projectile vomiting and a palpable “olive-shaped” mass in the epigastrium. Treatment is with a pyloromyotomy.

Answer D: Providing reassurance would not be appropriate due to this patient’s poor weight gain. Although most cases of gastroesophageal reflux are uncomplicated and self-resolve by 1 year of age, this patient’s symptoms should be addressed to ensure he is meeting his nutritional requirements.

Answer E: Switching to a hydrolyzed formula to eliminate cow’s milk and soy protein from the patient’s diet would be appropriate if the patient’s symptoms did not improve with changing position and thickening feeds.

Bullet Summary:
The most appropriate initial step in managing gastroesophageal reflux disease in infants is counseling on proper positioning and thickening feeds.


Question: A 25-year-old woman presents to her primary care physician complaining of recent hair growth along her jawline, now requiring her to shave every 2 days. She has not shaved in about a week. She has also gained about 10 pounds in the last several months, and her periods have become irregular over the last year. Her last menstrual period was 3 months ago. Her temperature is 98.6°F (37.0°C), pulse is 72/min, blood pressure is 136/86 mmHg, and respirations are 13/min. Her BMI is 26 kg/m^2. Her skin exam reveals hirsutism along the jawline and acanthosis nigricans in the axillary folds. Cardiopulmonary and abdominal exams are unremarkable. A pelvic exam reveals normal external genitalia, a mobile and non-tender 6-week-sized uterus, and no adnexal masses or tenderness. Transvaginal ultrasound is performed and shown in Figure A. This patient is at increased future risk of which of the following?

Answer: Endometrial carcinoma

Explanation:
This patient presents with hirsutism, oligomenorrhea, and multiple follicles on pelvic ultrasound, which is most consistent with polycystic ovarian syndrome (PCOS). PCOS is associated with an increased risk of endometrial carcinoma.

PCOS is an acquired endocrinopathy characterized by ovarian dysfunction and high rates of amenorrhea. Patients with PCOS are at risk for endometrial carcinoma due to unopposed estrogen exposure. Anovulation results in decreased progesterone, which prevents excessive endometrial build-up and thus increases the risk of endometrial hyperplasia and subsequent carcinoma. Increased adiposity in PCOS also increases estrogen, which is aromatized from testosterone in adipose cells, and further raises the risk for endometrial carcinoma. Treatment is with weight loss, metformin, and hormonal contraceptives.

Khan et al. review the genetic basis underlying PCOS. They discuss how this disease is the most common endocrinopathy in reproductive-age women resulting in anovulatory infertility. They recommend using multimodal methods to treat this disease.

Figure/Illustration A shows a transvaginal ultrasound of the ovary with many peripheral follicles (red circle). These findings are characteristic of PCOS.

Incorrect Answers:
Answer B: Ovarian cancer does not occur with increased incidence in patients with PCOS. They are at baseline risk and do not require additional screening. The rates of ovarian cancer increase with hereditary cancer syndromes such as BRCA mutation.

Answer C: Ovarian cyst rupture is not a complication of PCOS, as PCOS does not actually cause cysts (despite the name). The cystic spaces seen on ultrasound are immature follicles rather than cysts. Recurrent infections can lead to cysts and rupture.

Answer D: Type 1 diabetes mellitus is not associated with PCOS, but type 2 diabetes mellitus is. Type 2 diabetes can cause acanthosis nigricans via insulin resistance. Patients with recurrent bouts of pancreatitis are predisposed to diabetes mellitus.

Answer E: Virilization is not seen in PCOS, as the testosterone levels are elevated but not to the degree necessary to produce frank masculinization. If there is evidence of virilization, such as voice deepening or clitoromegaly the differential should be broadened to other diagnoses.

Bullet Summary:
Patients with PCOS are at increased risk of endometrial carcinoma as a result of unopposed estrogen from anovulation as well as aromatization in adipose tissue.


Question:
A 64-year-old woman presents to the emergency room with whole-body itching. She noticed her symptoms while in the bathtub at home. She has never had symptoms like this before. Over the previous several months she has had episodes of joint swelling and pain in her hands as well as redness, burning pain, and swelling of her hands and feet. Her medical history is significant for type 2 diabetes mellitus, hypertension, and osteoporosis for which she takes metformin, enalapril, and alendronate. She was found to have a deep vein thrombosis of her left leg 3 months prior to presentation. Her temperature is 98.6°F (37.0°C), pulse is 80/min, blood pressure is 135/85 mmHg, and respirations are 13/min. Physical exam is notable for a woman in discomfort with excoriations over the skin on her forearms. Laboratory tests are shown below.

Serum:
Na+: 135 mEq/L
Cl-: 100 mEq/L
K+: 5.0 mEq/L
HCO3-: 22 mEq/L
BUN: 19 mg/dL
Glucose: 130 mg/dL
Creatinine: 1.0 mg/dL

Hematocrit: 64%
Leukocyte count: 19,000 cells/mm^3 with normal differential
Platelet count: 900,000/mm^3

Which of the following is the most appropriate long-term treatment?

Answer: Hydroxyurea

Explanation:
This patient presents with polycythemia, leukocytosis, and thrombocytosis in the setting of pruritus after bathing, as well as episodes suggestive of acute gout flares. These findings are consistent with polycythemia vera, which can be treated with hydroxyurea.

Polycythemia vera is a malignancy of the bone marrow that results in the overproduction of red blood cells, platelets, and white blood cells. Classic symptoms include pruritus after hot baths as well as swelling, burning pain, and rubor of the hands and feet (erythromelalgia). Patients may also have gout due to increased cell turnover leading to hyperuricemia. Older patients (> 60 years old) and those with prior thrombosis should be treated with a myelosuppressive agent, most commonly hydroxyurea with or without aspirin. Therapeutic phlebotomy is often indicated on these patients.

Stuart and Viera review the evidence regarding the diagnosis and treatment of polycythemia vera. They discuss how treatment includes phlebotomy with the possible addition of myelosuppressive agents. They recommend consultation with a hematologist for any patients with this syndrome.

Incorrect Answers:
Answer A: Cyclophosphamide is a chemotherapeutic agent that is used in the treatment of certain leukemias and lymphomas, as well as severe symptoms of autoimmune disease. A malignancy would present with vague systemic symptoms, weight loss, malaise, and abnormalities detected on CBC. Cyclophosphamide is not used in the treatment of polycythemia vera.

Answer B: Diphenhydramine is a 1st-generation antihistamine that can be used to treat pruritus, but would not be indicated for the treatment of polycythemia vera which is the underlying condition. This treatment represents a symptomatic treatment versus an agent that addresses the underlying cause.

Answer C: Febuxostat is a xanthine oxidase inhibitor that is used to reduce uric acid levels in the management of chronic gout. Gout would present with acute severe joint pain (typically the great toe) with risk factors of alcohol use, obesity, and thiazide use. It is not used in the acute management of gout or in polycythemia vera.

Answer E: Prednisone is a glucocorticoid that is used in many different clinical situations but is not used in the management of polycythemia vera. It could be used in acute inflammatory conditions (like Crohn disease or granulomatosis with polyangiitis) or to reduce inflammation during a flare of asthma or COPD.

Bullet Summary:
Polycythemia vera presents with pruritus after bathing, erythromelalgia, and gout and should be treated with hydroxyurea with or without aspirin.


Question: A newborn boy is evaluated 30 minutes after birth. He was born at 39 weeks gestation to a 27-year-old primigravid mother via cesarean section for cervical insufficiency. The pregnancy was complicated by gestational diabetes and the amniotic fluid was clear. Upon delivery, the patient had strong respiratory effort and a strong cry. His Apgar scores at 1 and 5 minutes were 7 and 8, respectively. The patient now is exhibiting increased work of breathing and is progressively more tachypneic. His birth weight is 3,568 g (7 lb 14 oz). His temperature is 99.0°F (37.2°C), blood pressure is 60/44 mmHg, pulse is 146/min, and respirations are 72/min. On physical exam, the patient is grunting with nasal flaring and subcostal retractions. Breath sounds are decreased at the bases bilaterally. The patient has central cyanosis. His chest radiograph can be seen in Figure A. Which of the following is the most likely etiology of this patient’s presentation?

Answer: Transient tachypnea of the newborn

Explanation:
This newborn is presenting with increased work of breathing and progressive tachypnea in the 1st hour of life, which is consistent with a diagnosis of transient tachypnea of the newborn.

Transient tachypnea of the newborn presents with respiratory distress and marked tachypnea within 2 hours of delivery. Transient tachypnea of the newborn is caused by delayed resorption and clearance of alveolar fluid, which results in mild pulmonary edema. Chest radiography typically demonstrates bilateral perihilar streaking and hyperinflation of the lungs. Transient tachypnea of the newborn is benign and usually resolves by day 2 of life. The management of this condition is supportive.

Alhassen et al. review the evidence regarding the diagnosis and treatment of TTN. They discuss how this condition sometimes requires extended hospitalization and is associated with wheezing in childhood. They recommend using ultrasound to help make this diagnosis.

Figure/Illustration A demonstrates prominent vascular markings around the hilum (yellow arrows), and increased lung volumes on chest radiograph, which is consistent with transient tachypnea of the newborn.

Incorrect Answers:
Answer A: Meconium aspiration syndrome can cause respiratory distress in the immediate newborn period, but it would be unlikely in a patient with a history of clear amniotic fluid, and a more mild clinical picture. Meconium aspiration syndrome would be seen on chest radiograph as coarse, irregular infiltrates and hyper expansion. Treatment is with antibiotics and airway clearance.

Answer B: Neonatal respiratory distress syndrome is a disease of prematurity and does not often occur in infants born at term to healthy mothers. The chest radiograph in neonatal respiratory distress syndrome is also more likely to demonstrate low lung volumes. Treatment is with surfactant administration.

Answer C: Persistent pulmonary hypertension is a cause of respiratory distress in the newborn period, but a chest radiograph typically shows clear lungs. Treatment is with respiratory support as well as inhaled nitric oxide.

Answer E: Viral pneumonia is uncommon in the immediate newborn period. Bacterial pneumonia is more common but usually presents with signs of infection in the mother, which are not present in this case. Treatment is with broad-spectrum antibiotics.

Bullet Summary:
Transient tachypnea of the newborn presents with worsening tachypnea within 2 hours of delivery and is caused by pulmonary edema resulting from inadequate clearance of alveolar fluid.


Question:
A 4-day-old boy presents to the pediatrician with his mother for his 1st well visit. The patient was born at 36 weeks gestation to a 26-year-old primigravid mother via cesarean section for cervical incompetence. The patient required no resuscitation at birth and both mother and child were discharged from the hospital at 2 days of life. The patient has been exclusively breastfed since birth, and his mother reports that he feeds for 20-30 minutes every 2 hours. The patient urinates 7 times per day and has begun passing 2-3 stools per day that his mother describes as “grainy” and the color of “mustard.” His birth weight was 3670 g (8 lb 1 oz), and his current weight is 3487 (7 lb 11 oz). His temperature is 97.1°F (36.2°C), blood pressure is 57/42 mmHg, pulse is 140/min, and respirations are 38/min. On physical exam, the patient’s anterior fontanelle is soft and flat, and his eyes are moderately icteric. His abdomen is soft and non-distended. The patient has the physical exam finding seen in Figure A. His diaper can be seen in Figure B. Laboratory studies reveal the following:

Total bilirubin: 13 mg/dL
Conjugated bilirubin: 0.6 mg/dL

Which of the following is the most appropriate next step in management?

Order spot uric acid to creatinine ratio

Answer: Continue current breastfeeding regimen

Explanation:
This patient presents at day 4 of life with weight loss of 5% of his birth weight, uric acid crystals in his diaper, desquamation of the palms and soles, and unconjugated hyperbilirubinemia, which are normal findings in a newborn. The most appropriate next step in management is continuing his current breastfeeding regimen.

Healthy newborns may lose up to 7% of their birth weight in the first 5 days of life and exhibit dry, peeling skin on the palms and soles as the skin adapts to a drier environment outside the womb. Uric acid crystals that look like “brick dust” are also a normal finding in the diaper during the 1st week of life, as uric acid excretion is highest at birth. All newborns should be evaluated for signs of dehydration, including sunken fontanelles, dry mucous membranes, low urine output, excessive weight loss, and tachycardia. If these findings are not present, continued breastfeeding should be encouraged.

Westerfield et al. review the evidence regarding the benefits of breastfeeding. They discuss how breastfeeding is associated with decreased risk of atopic dermatitis and gastroenteritis. They recommend ensuring proper breastfeeding techniques.

Figure A demonstrates flaking and peeling of the soles (red circles), which is a normal finding in the 1st week of life.

Figure B demonstrates uric acid crystals (“brick dust”) in the diaper (red circle), which is another normal finding that is caused by high uric acid excretion in the 1st few days of life.

Incorrect Answers:
Answer A: Administering intravenous hydration would be appropriate for a severely dehydrated neonate who cannot tolerate hydration orally. This patient is not exhibiting signs of dehydration.

Answer C: Ordering a serum uric acid concentration may be part of an evaluation for Lesch-Nyhan syndrome, an X-linked recessive disorder of purine metabolism caused by deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT) that causes hyperuricemia and hyperuricosuria. The uric acid crystals found in this patient’s diapers are a normal finding in the 1st week of life. Treatment is supportive including allopurinol for gout.

Answer D: Ordering a spot uric acid to creatinine ratio would be an appropriate first step in evaluation for Lesch-Nyhan syndrome, but the uric acid crystals in this patient’s diaper are not concerning for Lesch-Nyhan syndrome. Treatment is supportive as well as with allopurinol for gout.

Answer E: Recommending increasing the frequency of breastfeeding would be appropriate for a dehydrated infant with excessive weight loss, but this patient’s weight loss is within the expected limits for the 4th day of life.

Bullet Summary:
Healthy newborns may present with desquamation of the skin and uric acid crystals in the diaper and continued breastfeeding should be encouraged if no signs of dehydration are present.


Question: A 45-year-old man presents to his primary care physician with a rash. He first noticed the rash 2 weeks prior and he endorses intermittent itchiness from the rash. His medical history is significant for chronic hepatitis C infection, hypertension, type 2 diabetes mellitus, and heart failure. The patient works as a butcher at a local meat processing shop and is sexually active with several partners. He does not use barrier protection. His temperature is 98.6°F (37.0°C), pulse is 90/min, blood pressure is 155/95 mmHg, and respirations are 12/min. On physical exam, his skin has the finding shown in Figure A. Fine, lace-like white lines are also noted on the patient’s buccal mucosa. Which of the following is the most likely diagnosis?

Answer: Lichen planus

Explanation:
This patient presents with several purple, polygonal, pruritic papules and plaques. These findings are most consistent with a diagnosis of lichen planus.

Lichen planus is an inflammatory skin disorder most commonly characterized by an eruption of Purple, Polygonal, Planar, Pruritic, Papules and Plaques (the 6 P’s), often on extensor surfaces such as the wrist. Development of fine white lines on the surfaces of skin lesions, as well as on the buccal mucosa (Wickham striae), are also characteristically seen in this disease. Concurrent hepatitis C infection is a risk factor for lichen planus. A skin biopsy will show a sawtooth infiltrate of lymphocytes at the dermal-epidermal junction. Treatment is with antihistamines for pruritus and topical steroids for localized disease as well as addressing the underlying cause.

Tziotzios et al. review the evidence regarding the diagnosis and treatment of lichen planus. They discuss how the molecular basis of this disorder is relatively unknown. They recommend making a clear diagnosis to allow for treatment.

Figure/Illustration A shows multiple purple, polygonal, papules and plaques on the wrist (red circles). These findings are characteristic of lichen planus.

Incorrect Answers:
Answer A: Atopic dermatitis most commonly presents with pruritic, lichenified plaques on the flexural surfaces. The mucous membranes are not involved. Treatment is with topical moisturizers and antihistamines for pruritus. This disease is also associated with other atopic conditions such as asthma and seasonal allergies.

Answer C: Prurigo nodularis is characterized by hypertrophic, dome-shaped papules that develop secondary to chronic scratching. The mucous membranes are not involved. Treatment is with avoidance of the triggering behavior such as scratching and antihistamines for pruritus.

Answer D: Psoriasis is characterized by silver, scaly plaques that bleed easily when the scale is physically removed (Auspitz sign). Patients with cutaneous psoriasis are at increased risk for the development of psoriatic arthritis. Psoriasis can be treated with topical corticosteroids as well as calcipotriene.

Answer E: Scabies is a cutaneous infection with the mite Sarcoptes scabei that presents with severe pruritus, especially in the intertriginous areas. Patients may have serpiginous scaling lesions that represent the burrowing of the mite through the skin, but mucous membrane lesions are absent. Treatment can include topical permethrin first line.

Bullet Summary:
Lichen planus presents with the 6 P’s – Purple, Pruritic, Polygonal, Planar, Papules and Plaques.


Question:
A 26-year-old man presents to his primary care physician with a 6-month history of increasing lower back pain. He first felt the pain while lifting boxes at work but thought that he had just strained a muscle. The pain appears to be worse in the mornings and after rest. Exercise and physical activity appear to temporarily make the pain better. He has taken acetaminophen and ibuprofen for the pain. He has no significant medical history and takes no medications. His temperature is 98.6°F (37.0°C), blood pressure is 115/70 mmHg, pulse is 70/min, and respirations are 12/min. On physical exam, he is found to have limited flexion and extension of his spine as well as tenderness to palpation over the insertion of his patellar tendons bilaterally. Results from laboratory tests are shown below:

Serum:
Erythrocyte sedimentation rate (ESR): 61 mm/hr
C-reactive protein (CRP): 36 mg/L (normal <10 mg/L)

Which of the following is the most accurate test for this patient's condition?

Answer: Magnetic resonance imaging

Explanation:
This young man presents with low back pain that is relieved by physical activity, decreased spinal mobility, enthesitis of his patellar tendons, and elevated ESR/CRP values most likely has ankylosing spondylitis (AS). The most accurate diagnostic test for early ankylosing spondylitis is MRI.

Multiple imaging tests can diagnose ankylosing spondylitis. Radiographs of the spine will show squaring of vertebrae with vertical or marginal syndesmophytes resulting in a "bamboo spine" appearance. The earliest radiographic sign is the erosion of the iliac side of the sacroiliac joint, but this finding is not sensitive in the early stages of the disease. MRI is sensitive in detecting sacroiliac inflammation, which makes this the best modality for early detection of ankylosing spondylitis in young patients. Initial therapy for ankylosing spondylitis includes lifestyle modifications (exercise, smoking cessation, physical therapy) and non-steroidal anti-inflammatory drugs (NSAIDs). Therapy for patients with inadequate response to NSAIDs includes tumor necrosis factor inhibitors (etanercept, infliximab, adalimumab) and interleukin 17 inhibitors (secukinumab, ixekizumab).

Jung et al. studied whether signs of inflammation on MRI are correlated with bone quality in patients with ankylosing spondylitis. The authors find that bone marrow edema is negatively correlated with the trabecular bone score. The authors recommend control of active bone inflammation to prevent osteoporosis in patients with ankylosing spondylitis.

Incorrect Answers:
Answer A: Bone scan will show inflammation in the sacroiliac joints, but this study lacks specificity for this disease compared with other inflammatory forms of arthritis.

Answer B: CT will show bony changes but not active inflammation, so it is most commonly used to diagnose cervical fractures in patients with ankylosing spondylitis. While it can support the diagnosis, it is less accurate than an MRI.

Answer D: Radiographs will show erosion of the iliac side of the sacroiliac joint, but this finding is not sensitive in the early stages of the disease when bony ankylosis has not yet occurred. Radiographs may be an appropriate initial test.

Answer E: Ultrasound is useful in evaluating muscle strains or tendon tears; however, it is not able to detect bony abnormalities and is therefore of limited use in ankylosing spondylitis.

Bullet Summary:
MRI is the most sensitive and accurate test for the early detection of ankylosing spondylitis.


Question:
A 69-year-old man presents to his primary care provider for a general checkup. He has a medical history of type 2 diabetes mellitus, hypertension, depression, obesity, and a myocardial infarction 7 years ago. The patient's prescribed medications are metoprolol, aspirin, lisinopril, hydrochlorothiazide, fluoxetine, metformin, and insulin. The patient has not been filling his prescriptions regularly and can not remember what medications he has been taking. His temperature is 99.5°F (37.5°C), pulse is 96/min, blood pressure is 180/120 mmHg, respirations are 18/min, and oxygen saturation is 97% on room air. Laboratory values are obtained and the results are shown below:

Serum:
Na+: 139 mEq/L
K+: 4.3 mEq/L
Cl-: 100 mEq/L
HCO3-: 24 mEq/L
BUN: 7 mg/dL
Glucose: 170 mg/dL
Creatinine: 1.2 mg/dL

Which of the following cardiac findings would be expected on physical exam?

Answer: Heart sound before S1

Explanation:
This patient who presents with poorly managed hypertension over a long period of time most likely has compensatory hypertrophy of the heart. The most likely heart sound in this patient is an S4 gallop that occurs immediately before S1.

Chronic hypertension that is poorly controlled can lead to concentric hypertrophy of the heart. This adaptive mechanism creates a stiff and non-compliant left ventricle. When blood enters this stiff ventricle, the typical sound heard is an S4 heart sound which is heard right before S1. This sound represents the atrial kick that pushes blood against a non-compliant left ventricle in the last phase of diastole. Treatment is by meticulous control of the underlying cardiac pathophysiology such as hypertension.

Kino et al studied the relationship between the S1 and S4 heart sounds in aging patients. They found that an S4 heart sound can be missed in cases of prominent S1 splitting. They recommend studying heart sounds in order to not accidentally miss an S4 finding.

Incorrect Answers:
Answer A: Fixed splitting of S1 and S2 describes an atrial septal defect. The atrial septic defect allows blood to communicate between both sides of the heart and equalizes atrial pressures. Asymptomatic patients may not need treatment but surgical repair of the defect should be performed in symptomatic cases.

Answer B: A heart sound after S2 suggests a S3 heart sound which would be found in fluid-overloaded states such as heart failure. This post-systolic gallop is the result of incomplete emptying of the ventricle prior to the start of diastole so that the blood from the atria falls against an already full chamber. Treatment is with diuresis and treatment of the underlying heart failure.

Answer D: A holosystolic murmur heard at the apex describes mitral valve regurgitation. This would be possible if a papillary muscle had ruptured in an acute myocardial infarction. Treatment is with mitral valve replacement in symptomatic patients.

Answer E: A normal S1 and S2 is possible but is less likely given this patient's long-standing history of poorly managed hypertension. Hypertension usually causes concentric hypertrophy of the ventricle and thereby leads to increased resistance to diastolic filling.

Bullet Summary:
An S4 heart sound is created by blood entering a stiff and non-compliant left ventricle and is often heard in patients with long-standing hypertension.


Question: A 32-year-old G1P0 woman delivers a boy at 40 weeks and 3 days of gestation. The delivery is uncomplicated and the neonate has Apgar scores of 9 and 9 at 1 and 5 minutes respectively. After 15 minutes, he attempts to nurse for the 1st time. His mother notices that his face, chest, and extremities turn dusky blue during nursing. She also notes that he seems to be snoring loudly and breathing very quickly. When she removes him from her breast, he begins to cry and his color improves. The neonate’s prenatal course was unremarkable, and his mother has a medical history of asthma with occasional albuterol inhaler use. As the infant is resting, vital signs are taken. His temperature is 98.2°F (36.7°C), pulse is 130/min, respirations are 45/min, and oxygen saturation is 97% on room air. A physical exam demonstrates well-perfused skin but is notable for the facial features shown in Figure A. Which of the following is most likely to be observed in this neonate?

Answer: Inability to pass a nasogastric tube

Explanation:
This neonate presents with central cyanosis upon feeding, resolution with crying, and midface hypoplasia on exam, most consistent with choanal atresia. A nasogastric (NG) tube would not pass through the nasal canal.

Choanal atresia is caused by failed recanalization of the nasal fossae during fetal development. This disease typically presents with noisy breathing, cyanosis when feeding, and improvement with crying and the use of the mouth for breathing. Cyanosis in this condition affects the entire body as opposed to just the hands and feet. Bilateral atresia often presents early in life. Clinical suspicion of choanal atresia should prompt an attempt to pass an NG tube, which will meet resistance at the posterior part of the nasal canal. Treatment is with the surgical creation of the nasal passages.

Lesciotto et al. review the diagnosis and pathophysiology of patients with choanal atresia. They discuss how this condition is often comorbid with craniosynostosis. They recommend a better understanding of how these patients develop decreased nasal airway volume.

Figure/Illustration A is a clinical photograph showing midface hypoplasia with a poorly developed nasal bone (red circle). These findings are consistent with a diagnosis of choanal atresia.

Incorrect Answers:
Answer A: Areflexia in all extremities may be seen in spinal muscular atrophy, a genetic condition that causes loss of motor neurons. This condition may cause difficulty feeding due to weakness of the oropharyngeal and glossopharyngeal muscles, but it typically does not cause cyanosis. Treatment is with steroid use and nusinersen.

Answer B: Digital clubbing can result from chronic hypoxemia, as seen in conditions such as cystic fibrosis. It would be unexpected for a neonate to have clubbing as the characteristic finger appearance depends on the long-term deposition of platelet-derived growth factor and would not develop within minutes. This patient also does not have cyanosis at baseline. Treatment of cystic fibrosis is with enzyme repletion and respiratory therapy.

Answer D: Markedly decreased lung volume can occur in congenital diaphragmatic hernia, in which the abdominal contents herniate into the chest cavity and cause pulmonary hypoplasia. Infants may present with cyanosis due to respiratory failure, but there would be no association with feeding or improvement with crying. Vital signs would also be abnormal. Treatment is with surgical repair of the diaphragm.

Answer E: A patent foramen ovale occurs when the connection between the left and right atria does not close soon after birth. It does not result in cyanosis and is typically asymptomatic, though it may cause paradoxical embolism and stroke later in life. Treatment of a symptomatic patent foramen ovale is surgical closure of the defect.

Bullet Summary:
Choanal atresia presents with cyanosis and respiratory distress that worsens with feeding and improves with crying associated with failure to pass a nasogastric tube.


Question: A 69-year-old man presents to his primary care physician for a general checkup. The patient works as a farmer and gardens in his spare time. He has a medical history of poorly managed type 2 diabetes mellitus and irritable bowel syndrome. His current medications include lisinopril, metformin, insulin, fiber supplements, and a multivitamin. On physical exam, there is a calm, obese gentleman. Inspection of the patient's scalp reveals the finding shown in Figure A. The patient is sent home and instructed to keep a blood glucose journal. Three months later, the patient returns with his glucose journal. In addition, he complains of a cut on his scalp that is not seeming to heal. The patient's glucose journal reveals an average blood glucose of 175 mg/dL. His temperature is 98.8°F (37.1°C), blood pressure is 134/86 mmHg, pulse is 80/min, and respirations are 13/min. On inspection of the patient's scalp, the finding in Figure B is noted. Which of the following is the most likely diagnosis?

Answer: Squamous cell carcinoma

Explanation:
This patient with a non-healing ulcer on the site of a previous actinic keratosis most likely has sustained progression of the lesion to squamous cell carcinoma.

Squamous cell carcinoma (SCC) is a common dermatological malignancy. Patients can present with actinic keratosis, which is a pre-malignant lesion in sun-exposed areas. These lesions can progress to squamous cell carcinoma if risk factors such as sun exposure continue. The presentation of SCC is typically an ulcerative lesion in a sun-exposed area. A biopsy will demonstrate atypical keratinocytes and malignant cells, invasion into the dermis, and keratin “pearls” on histology. Treatment is with wide local surgical excision with histologic confirmation of negative margins.

Waldman and Schmults present a review of the evidence regarding the epidemiology and treatment of squamous cell skin cancer. They discuss how the incidence of this disease continues to increase due to an aging population. They recommend local excision and treatment due to the risk of metastasis.

Figure/Illustration A is a clinical photograph demonstrating a rough scaly patch on the skin (red circle). This finding is consistent with actinic keratosis, which is a pre-malignant lesion typically found on sun-exposed areas.

Figure/Illustration B demonstrates an ulcerative lesion with wound formation on the skin (red circle). This finding is consistent with squamous cell carcinoma, a malignant lesion that can progress from actinic keratosis.

Incorrect Answers:
Answer A: Actinic keratosis represents a pre-malignant condition that this patient initially presented with (as demonstrated in Figure A). His current presentation reflects SCC, a progression from actinic keratosis given the new ulceration and non-healing wound.

Answer B: Basal cell carcinoma presents with a shiny or pearly appearance, rather than the ulcerative appearance that is seen in SCC. This disease should be treated with surgical excision.

Answer C: Melanoma presents with a pigmented lesion that has an irregular border, an uneven shape, and areas that differ in pigmentation. Patients with melanoma should undergo surgical staging as this disease can become metastatic and should be treated with surgical excision.

Answer D: Poor wound healing secondary to diabetes would be possible if there was a history of trauma to the scalp. The history of actinic keratosis and the current ulcerative lesion, point more toward a diagnosis of SCC. Non-healing wound in patients with diabetes are usually located on the foot rather than on the scalp.

Bullet Summary:
Actinic keratosis is a pre-malignant lesion that occurs in sun-exposed areas that can progress to squamous cell carcinoma.


Question: A 69-year-old man presents to his primary care physician for trouble sleeping. He recently retired from working the day shift at a cemetery. When the patient retired, his goal was to finally be able to go out with his wife; however, he finds that he is unable to stay awake past 6 pm in the evening. His wife is disappointed that they cannot do any activities in the evening together. The patient has tried drinking caffeine but finds that it does not help. The patient’s wife claims that the patient seems to sleep peacefully, and the patient states he feels rested when he awakes. The patient has a medical history of irritable bowel syndrome which is managed with fiber supplements. His temperature is 98.6°F (37°C), blood pressure is 125/83 mmHg, pulse is 87/min, and respirations are 11/min. The patient’s neurological exam is within normal limits. Which of the following is the most likely diagnosis?

Answer: Advanced sleep phase disorder

Explanation:
This patient is presenting with difficulty staying awake in the early evening suggesting a diagnosis of advanced sleep phase disorder (also known as advanced sleep phase syndrome).

Advanced sleep phase disorder can present in patients of all ages. Patients will experience difficulty staying awake in the early evening (5 to 8 pm); however, they will typically sleep a normal quantity of hours. These patients generally feel well rested in the morning and are able to function normally during the day. This condition can impair social activities that occur in the evening, which can cause distress to the patient. The diagnosis of advanced sleep phase disorder can be made when these symptoms are present in addition to an absence of another organic cause (such as obstructive sleep apnea). Treatment is with bright light visual stimulation therapy and reconditioning of circadian rhythms.

Yaremchuk reviews the diagnosis and treatment of patients with sleep phase disorder. She discusses how sleep disorders such as advanced sleep phase disorder should be distinguished from normal aging. She recommends intervening when sleep quality is compromised as it reduces quality of life in the elderly.

Incorrect Answers:
Answer B: Chronic insomnia will present with trouble falling asleep or staying asleep, often alternating with other sleep pathologies. This patient does not claim to have any trouble falling or staying asleep. He also feels well rested in the morning so his sleep quality is adequate. Treatment of insomnia may include melatonin and sleep hygiene.

Answer C: Delayed sleep phase disorder typically presents in younger patients with difficulty falling asleep early. These patients will often fall asleep very late and struggle to wake up early for obligations such as school or work. Treatment is with melatonin and sleep hygiene interventions.

Answer D: Normal aging presents with patients claiming that their sleep is less restful in the absence of an organic cause (such as obstructive sleep apnea). As patients age, it is natural for all phases of their sleep to shorten. However, it is not normal for this patient to have such difficulty staying awake in the early evening, so advanced sleep phase disorder is a more likely diagnosis.

Answer E: Obstructive sleep apnea presents with fatigue, morning headaches, and non-restful sleep. Patients will typically snore loudly and typically are overweight. This patient does not have any of these risk factors or symptoms in his history. Treatment is with positive airway pressure machines and weight loss.

Bullet Summary:
Advanced sleep phase disorder presents with difficulty staying awake in the early evening that impairs social functioning.


Question: A 3-week-old girl presents with her parents to her pediatrician for a routine visit. The child is sleeping at regular 2-hour intervals and feeding and stooling well. The parents have noticed a “swelling of the belly button.” Cord separation occurred at 7 days of age. The swelling seems to come and go but is never larger than the size of a blueberry. They deny any drainage from the swelling. Her temperature is 98.6°F (37°C), blood pressure is 68/43 mmHg, pulse is 128/min, and respirations are 32/min. On physical exam, the child is in no acute distress and appears developmentally appropriate for her age. Her abdomen is soft and non-tender with a soft, 1 cm bulge at the umbilicus. The bulge increases in size when the child cries and can be easily reduced inside the umbilical ring without apparent pain. Which of the following is the most appropriate next step in management?

Answer: Expectant management

Explanation:
This infant presents with a soft, 1 cm bulge at the umbilicus that is easily reducible inside the umbilical ring, which suggests a diagnosis of an umbilical hernia. Most umbilical hernias in children resolve spontaneously and can be managed expectantly.

An umbilical hernia is a protrusion of bowel, omentum, or preperitoneal fat through the umbilical ring that can change in size with increases in intra-abdominal pressure (e.g., crying). The majority of umbilical hernias in patients under 5 years of age resolve spontaneously. The indications for surgery on umbilical hernias in that age group are limited to incarcerated hernias or hernias > 1.5 cm in diameter. Incarcerated hernias present with an irreducible mass that is associated with pain and erythema. Surgical closure may be considered in patients whose defects fail to close by the age of 5.

Chirdan et al. review the evidence regarding the diagnosis and treatment of pediatric patients with an incarcerated umbilical hernia. They discuss how most patients with hernias resolve spontaneously before 5 years of age but a small number will have incarcerated hernias that require surgery earlier. They recommend active observation of patients to diagnose incarceration earlier.

Incorrect Answers:
Answer A: Elective surgical management later on in childhood is usually not required to manage umbilical hernias as most umbilical hernias in patients less than 5 years of age close spontaneously. Hernias that persist past age 5 can be closed surgically in an elective fashion.

Answer C: Histopathologic evaluation would be the most appropriate next step in management if the patient had an unknown umbilical mass, such as an umbilical granuloma or polyp. Umbilical granulomas form shortly after birth from excess tissue at the base of the umbilicus and can be treated topically, whereas umbilical polyps are firm masses of omphalomesenteric duct or urachal embryologic remnants and require surgical excision.

Answer D: Immediate surgical management is required in patients with incarcerated hernias, but this patient’s hernia is easily reducible and < 1.5 cm. Incarcerated hernias present with an irreducible mass that is associated with pain and erythema.

Answer E: Thyroid hormone replacement would be indicated in newborns that suffer from hypothyroidism which could present with an umbilical hernia. This patient has no other symptoms of hypothyroidism such as dry skin, hypoactive reflexes, constipation, poor muscle tone, and coarse facial features.

Bullet Summary:
Umbilical hernias are common in children and usually resolve spontaneously in children under 5 years of age.


Question: A 3-year-old boy presents with his parents to a pediatrician for a new patient visit. The child was recently adopted and little is known about his medical or family history. The child seems to be doing well, but the patient is much larger than any of the other 3-year-olds in his preschool class. He eats a varied diet at home and with limited juice and snack foods. His temperature is 98.6°F (37°C), blood pressure is 101/67 mmHg, pulse is 110/min, and respirations are 24/min. On physical exam, the patient is in the 73rd percentile for weight, 99th percentile for height, and 86th percentile for head circumference. He appears mildly developmentally delayed. He has a fair complexion and tall stature with a prominent sternum. The patient also has joint hypermobility and hyperelastic skin. He appears to have poor visual acuity and is referred to an ophthalmologist, who finds downward lens subluxation of the right eye. This child is most likely to develop which of the following complications?

Answer: Thromboembolic stroke

Explanation:
This patient presents with Marfanoid habitus, joint hypermobility, hyperelastic skin, developmental delay, and downward lens subluxation, which suggests a diagnosis of homocystinuria. Homocystinuria predisposes to thromboembolic events such as stroke.

Although homocystinuria shares many features with Marfan syndrome, patients with homocystinuria also present with a fair complexion, intellectual disability, and downward subluxation of the lens (instead of the upward subluxation seen in Marfan syndrome). Patients with homocystinuria are also at an increased risk of thromboembolic events that disproportionally affect the cerebral vessels. Similar to Marfan syndrome, patients have phenotypic features of a Marfanoid habitus, including tall stature, long limbs, arachnodactyly, joint hypermobility, skin hyperelasticity, pectus deformity, and scoliosis. Treatment includes vitamin B6 supplementation.

Hasan et al. review the evidence regarding diseases associated with homocystinuria. They discuss how this disease is associated with cancer and Alzheimer disease. They recommend screening for this disease.

Incorrect Answers:
Answer A: Aortic dissection is a complication of Marfan syndrome, an autosomal dominant mutation of the fibrillin-1 gene. It is also associated with elevated homocysteine levels. Although Marfan syndrome shares many features with homocystinuria, the fair complexion, and intellectual disability seen in this patient are specific to homocystinuria. Treatment involves avoidance of contact sports and beta blockers.

Answer B: Medullary thyroid cancer is part of the syndrome of multiple endocrine neoplasia type 2B (MEN2B), which is caused by a mutation in the RET proto-oncogene. Patients with MEN2B present with Marfanoid habitus, but they do not present with the other features described in this vignette, including fair complexion, intellectual disability, and downward lens subluxation. Treatment is with surgical excision of tumors.

Answer C: Osteoarthritis is a complication of Ehlers-Danlos syndrome (EDS). Although patients with EDS may present with many of the phenotypic features of both Marfan syndrome and homocystinuria, patients are much less likely to have lens subluxation. Osteoarthritis may be seen with higher incidence in patients with homocystinuria. Treatment is with brace support of unstable joints.

Answer E: Wilms tumor is associated with Beckwith-Wiedemann syndrome (BWS), a pediatric overgrowth disorder usually caused by a mutation at chromosome 11p15. BWS presents with macrosomia (“gigantism”), which is defined as height and weight > 97th percentile. BWS additionally presents with omphalocele, hemihyperplasia, visceromegaly, neonatal hypoglycemia, and other embryonal tumors, including hepatoblastoma and neuroblastoma. Treatment is with surgical correction of defects.

Bullet Summary:
Homocystinuria presents with Marfanoid habitus, fair complexion, intellectual disability, downward lens subluxation, and an increased risk of thromboembolic events.


Question: A 16-year-old boy presents to an ophthalmologist with blurry vision. Over the past several months, he has had increasing difficulty seeing the board from the back of the classroom at school. The patient is otherwise doing well in school and enjoys playing basketball. His medical history is otherwise significant for scoliosis which is managed by an orthopedic surgeon. His family history is significant for a mother with type 2 diabetes mellitus and a father who underwent aortic valve replacement last year. His temperature is 98.6°F (37°C), blood pressure is 115/71 mmHg, pulse is 72/min, and respirations are 12/min. On physical exam, the patient is tall for his age and has long arms. He has 20 degrees of thoracic scoliosis, which is stable from previous exams. On slit-lamp examination, the patient is found to have bilateral upward lens subluxation and is prescribed corrective lenses. Which of the following is the most likely cause of this patient’s symptoms?

Answer: Mutation of chromosome 15

Explanation:
This patient presents with tall stature, upward lens subluxation, and a family history of aortic valve disease, which suggests a diagnosis of Marfan syndrome. Marfan syndrome is caused by an autosomal dominant mutation in the fibrillin-1 gene on chromosome 15.

The fibrillin-1 gene codes for a glycoprotein in the extracellular matrix of connective tissue. Patients with Marfan syndrome classically present with a triad of musculoskeletal, ocular, and cardiovascular symptoms. The musculoskeletal findings include tall stature, long limbs, arachnodactyly, pectus excavatum, joint hypermobility, skin hyperelasticity, and scoliosis. Patients with Marfan syndrome also often present with upward lens subluxation, and they are at increased risk of cardiac disease, including aortic regurgitation and aortic dissection. Treatment is symptomatic with avoidance of contact sports, beta-blockers, and valve repair to prevent cardiac complications.

Bitterman and Sponseller review the evidence regarding the diagnosis and treatment of Marfan syndrome. They discuss how skeletal manifestations are often the initial presentation of this condition leading to diagnosis. They recommend screening for patients who are suspected to have this disease.

Incorrect Answers:
Answer A: Defective metabolism of methionine describes homocystinuria, an autosomal recessive deficiency of cystathionine synthase. Although patients with homocystinuria may also have tall stature, arachnodactyly, and pectus deformity, the lens dislocation in homocystinuria is downward rather than upwards. Patients with homocystinuria also tend to have a fair complexion, intellectual disability, and thrombophilia. Treatment includes vitamin B6 supplementation.

Answer B: Extra copy of a sex chromosome describes Klinefelter syndrome (47,XXY). Although patients with Klinefelter syndrome classically present with tall stature, they do not have the other clinical features found in this patient, including joint hypermobility and lens subluxation. Patients with Klinefelter also present with hypogonadism and azoospermia. Treatment is supportive

Answer D: Mutation of COL5A1 or COL5A2 leads to Ehlers-Danlos syndrome, a collagen disorder that commonly presents with joint hypermobility, skin hyperextensibility, and skin fragility with easy bruising. Ehlers-Danlos would not explain this patient’s lens subluxation. Treatment may include bracing of unstable joints.

Answer E: Mutation of RET proto-oncogene describes multiple endocrine neoplasia type 2B (MEN2B). Patients with MEN2B may present with Marfanoid habitus and are predisposed to medullary thyroid cancer, pheochromocytoma, and mucosal neuromas. MEN2B would not explain lens subluxation. Treatment is with surgical resection of tumors.

Bullet Summary:
Marfan syndrome is caused by an autosomal dominant mutation in the fibrillin-1 gene on chromosome 15 and presents with a triad of musculoskeletal, ocular, and cardiovascular findings.


Question: A 76-year-old woman is brought to a primary care physician by her daughter who is concerned about her mother's growing inability to take care of herself. Initially, she attributed her mother's forgetfulness and word-finding difficulties to normal aging, but over the past few years, her mother's memory has worsened, her mood has grown more irritable, and her mother has been found wandering the neighborhood unsure of how to get home. Her medical history includes type 2 diabetes mellitus which is well-controlled with metformin. On exam, her temperature is 98.2°F (36.8°C), blood pressure is 115/82 mmHg, pulse is 73/min, respirations are 12/min, and oxygen saturation is 99% on room air. Cardiopulmonary exam reveals normal S1 and S2, no murmurs, and clear lungs bilaterally. She scores 16/30 on the Montreal Cognitive Assessment (MoCA) test. Which of the following is the most likely diagnosis?

Answer: Alzheimer dementia

Explanation:
This elderly patient who presents with slowly progressive memory loss, language difficulties, and progression to inability to care for herself most likely has Alzheimer dementia.

Alzheimer dementia is a neurodegenerative disorder that is characterized by a gradual and progressive cognitive decline (memory loss, visuospatial and language deficits, impaired judgment), difficulties with executive function or carrying out activities of daily living, and sometimes psychiatric disturbances and behavioral changes (apathy, irritability, social isolation). It is the most common cause of dementia and its risk factors include increasing age, female gender, family history, and trisomy 21 (due to the amyloid precursor protein found on chromosome 21). This is a clinical diagnosis based on cognitive testing (such as the Montreal Cognitive Assessment or the mini-mental status exam) and ruling out other causes of dementia (vitamin B12 deficiency, depression, or hypothyroidism).

Weller et al. review the current understanding of Alzheimer dementia pathophysiology. They discuss recent advances in clinical evaluation and treatment. They recommend having a high index of suspicion for the disease in elderly patients who appear to be regressing in their ability to take care of themselves.

Incorrect Answers:
Answer B: Creutzfeldt-Jakob disease is a rapidly progressive neurodegenerative disorder caused by a prion protein that is fatal, leading to death usually within 1 year of illness onset. Dementia progresses rapidly in this disease and is sometimes associated with startle myoclonus.

Answer C: Frontotemporal dementia (FTD) is characterized primarily by disinhibition, apathy, or aphasia as a result of atrophy of the frontal and temporal lobes. It tends to occur at a younger age than does Alzheimer dementia. Behavioral changes are often the first noticeable symptom in FTD while they tend to occur later in Alzheimer disease progression. Problems with visuospatial orientation are more common in Alzheimer dementia than in FTD.

Answer D: Normal pressure hydrocephalus (NPH) typically presents with a triad of dementia, gait instability (specifically magnetic gait, marked by an inability to lift feet off the floor), and urinary incontinence. In NPH, excess cerebrospinal fluid accumulates in the brain's ventricles, and treatment involves drainage of that fluid, usually via surgical placement of a shunt.

Answer E: Vascular dementia typically presents as stepwise cognitive decline in the setting of stroke or brain injury and usually occurs in patients with the same risk factors as stroke, such as hypertension, hyperlipidemia, peripheral arterial disease, and smoking. This patient has neither hypertension nor stepwise decline.

Bullet Summary:
Alzheimer dementia presents with slowly progressive dementia, typically manifesting with memory loss, visuospatial and language difficulties, impaired judgment, and inability to care for oneself.


Question: A 9-hour-old newborn girl is found in the newborn nursery with diffuse swelling of the scalp not present at birth. The child was born at 38 weeks of gestation to a 28-year-old G3P3 mother. The mother went into spontaneous labor but the delivery was complicated by a prolonged 2nd stage of labor. A vacuum-assisted vaginal delivery was eventually performed. The child’s Apgar scores were 8 and 9 at 1 and 5 minutes, respectively. The pregnancy was complicated by preeclampsia in the mother which was well-controlled throughout the pregnancy. Her temperature is 98.6°F (37°C), blood pressure is 67/43 mmHg, pulse is 135/min, and respirations are 34/min. On physical exam, she appears to be in mild distress and has a 4x5 cm ecchymotic area of swelling over the bilateral parietal bones. Serial assessments of the child’s head circumference over the next 12 hours show no change in the size of the swelling. This patient’s condition most likely affects which of the following spaces or potential spaces?

Between periosteum and galea aponeurosis

Answer: Between scalp and galea aponeurosis

Explanation:
This patient presents following a vacuum-assisted vaginal delivery with an ecchymotic swelling of the scalp that crosses the midline, which suggests a diagnosis of caput succedaneum. Caput succedaneum is caused by bleeding between the skin and the galea aponeurosis.

Caput succedaneum is an uncommon extracranial injury that occurs during a traumatic birth, particularly in deliveries in which a vacuum-assist device is used. It involves bleeding between the skin of the scalp and the galea aponeurosis. Unlike a cephalohematoma, caput succedaneum lesions may cross the suture lines of the cranial bones. Caput succedaneum is typically described as fluctuant and ecchymotic, and the swelling usually self-resolves within a few days. Treatment is supportive though patients may occasionally require phototherapy if they develop high levels of bilirubin. Transfusion is indicated if there is significant anemia present (though this is uncommon).

Jacob and Hoerter present evidence regarding the diagnosis and treatment of patients with caput succedaneum. They discuss how this lesion commonly crosses cranial suture lines as well as the midline. They recommend differentiating this disease from more malignant etiologies such as intracranial hemorrhage.

Incorrect Answers:
Answer A: Bleeding between the dura and arachnoid mater describes a subdural hematoma. Subdural hematomas are the most common type of intracranial hemorrhage found in neonates, but they usually present with more serious signs of respiratory depression, apnea, or seizures. Patients with a subdural hematoma should be evaluated for non-accidental trauma. Treatment of expanding lesions may require surgical decompression.

Answer B: Bleeding between the periosteum and galea aponeurosis describes a subgaleal hemorrhage, an uncommon but serious complication of traumatic birth. Like caput succedaneum, subgaleal hemorrhages occur most commonly in newborns delivered via vacuum-assisted delivery, but the swelling in a subgaleal hemorrhage involves the entire scalp. Patients may also present with signs of extensive blood loss and neurological disturbances. Treatment involves resuscitation with fluids or blood and possibly neurosurgical intervention.

Answer C: Bleeding between the periosteum and skull describes a cephalohematoma. Cephalohematoma occurs in newborns and is caused by the rupture of the blood vessels crossing the periosteum. They are usually secondary to a prolonged second stage of labor and, unlike caput succedaneum, do not cross suture lines. The treatment for these lesions is supportive as most of these lesions resolve spontaneously.

Answer E: Bleeding into the lateral ventricles describes an intraventricular hemorrhage. Intraventricular hemorrhage is associated with premature delivery and usually presents with neurological symptoms. Neurologic findings include seizures, apnea, respiratory depression, or asymmetric reflexes. Treatment may involve urgent surgical decompression to prevent herniation.

Bullet Summary:
Caput succedaneum is an extracranial injury caused by bleeding between the skin of the scalp and the galea aponeurotica in neonates.


Question:
A 6-hour-old newborn boy is noted to have a “lump on his head” by his mother. She denies that the lump was present at birth and is concerned about an infection. The child was born at 39 weeks gestation to a 34-year-old G2P2 mother by vacuum-assisted vaginal delivery after prolonged labor. His birth weight was 3.8 kg (8.4 lb) and his length and head circumference are at the 40th and 60th percentiles, respectively. The mother was diagnosed during this pregnancy with gestational diabetes mellitus and received prenatal care throughout. All prenatal screening was normal and the 20-week anatomy ultrasound was unremarkable. His temperature is 98.6°F (37°C), blood pressure is 65/42 mmHg, pulse is 131/min, and respirations are 36/min. On physical exam, the child is in no acute distress. He has a 3x3 cm fluctuant swelling over the right parietal bone that does not cross the midline. There is no discoloration of the overlying scalp. Laboratory testing is performed and reveals the following:

Total bilirubin: 5.5 mg/dL
Direct bilirubin: 0.7 mg/dL

Which of the following is the most appropriate next step in management?

Answer: Observation only

Explanation:
This patient presents with a fluctuant swelling of the scalp that is limited by suture lines, which is the classic description of a cephalohematoma. The majority of cases of cephalohematoma self-resolve, thus the most appropriate next step in management is observation.

A cephalohematoma is a relatively common traumatic birth injury that occurs after prolonged labor or instrumentation due to rupture of the periosteal bridging veins. Because bleeding through these veins is slow, they typically present several hours after birth with a fluctuant swelling of the scalp that is limited by suture lines. The majority of cases self-resolve between 2 weeks to 3 months. In rare cases, the sequestration of blood in the cephalohematoma may cause an unconjugated hyperbilirubinemia that requires phototherapy but this is a rare complication. Treatment is with reassurance and outpatient monitoring.

Raines et al. review the evidence regarding the diagnosis and treatment of cephalohematoma. They discuss how this injury presents gradually and does not cross suture lines. They recommend conservative treatment.

Incorrect Answers:
Answer A: An incision and drainage procedure is contraindicated in cephalohematoma without signs of infection, such as erythema of the skin overlying the swelling. In cases where the cephalohematoma is thought to be secondarily infected, patients should undergo incision and drainage to prevent osteomyelitis. Patients would present with increasing pain, erythema, and systemic findings such as fever.

Answer B: Intensive phototherapy may be used to manage the unconjugated hyperbilirubinemia that may occur due to cephalohematoma, but the majority of cases resolve spontaneously. The unconjugated hyperbilirubinemia found in this patient does not necessitate phototherapy. Unconjugated bilirubin is produced due to the metabolism of hemoglobin.

Answer C: Neurosurgical decompression may be necessary to manage other neonatal birth injuries, such as intracranial hemorrhages. Because a cephalohematoma involves bleeding between the periosteum and skull (i.e., outside of the skull), it does not require neurosurgical intervention. Intracranial hemorrhages would present with asymmetric reflexes or obtundation.

Answer E: Red blood cell transfusions are sometimes necessary to manage intracranial hemorrhages in neonates with significant blood loss. They are not usually required to manage cephalohematoma as the bleeding in this condition is limited by the suture lines. Patients who are tachycardic or hypotensive may require transfusion.

Bullet Summary:
Most cases of cephalohematoma resolve spontaneously but can sometimes present with an unconjugated hyperbilirubinemia that requires treatment with phototherapy.


Question: A 41-year-old man presents to his primary care provider after seeing bright red blood in the toilet bowl after his last 2 bowel movements. He reports that he also noticed some blood mixed with his stool. The patient denies abdominal pain or any changes in his stool habits. He notes a weight loss of 8 pounds in the last 2 months with no changes in his diet or exercise habits. His medical history is significant for an episode of pancreatitis 2 years ago for which he was hospitalized for several days. He drinks 2-3 beers on the weekend and he has never smoked. He has no family history of colon cancer. His temperature is 97.6°F (36.4°C), blood pressure is 135/78 mmHg, pulse is 88/min, and respirations are 14/min. On physical exam, his abdomen is soft and non-tender to palpation. Bowel sounds are present, and there is no hepatomegaly. Which of the following is the most appropriate next step in management?

Answer: Colonoscopy

Explanation:
This patient presents with hematochezia and weight loss, which raises concern for colorectal cancer. The most appropriate next step in management is performing a colonoscopy.

The differential diagnosis of hematochezia includes colorectal cancer, inflammatory bowel disease, diverticulosis, and hemorrhoids. The evaluation depends in large part on the age of the patient and whether the patient presents with alarm symptoms such as weight loss, abdominal pain, change in bowel habits, or iron-deficiency anemia. If the patient is over the age of 50, has alarm symptoms, or has a family history of colorectal cancer, the evaluation should begin with a colonoscopy to rule out malignancy. If the patient is between the ages of 40 and 50 and without other red flags, the patient can elect to undergo sigmoidoscopy as a less invasive procedure than colonoscopy. If the patient is under the age of 40 and without alarm symptoms, the workup may begin with an anoscopy to first evaluate for hemorrhoids. Once cancer has been ruled out, additional evaluation for chronic inflammatory diseases such as ulcerative colitis can be conducted.

Church presents evidence regarding the current use of colonoscopy. He discusses how the detection of neoplasia during colonoscopy is suboptimal despite its use as the current screening tool of choice. He recommends understanding which patients are missed and how to better detect neoplasias in these patients.

Incorrect Answers:
Answer A: Abdominal CT might be used to evaluate for metastases if the diagnosis of colorectal cancer is confirmed but it would not be used to diagnose the primary malignancy. A CT scan would be the most appropriate initial step in diagnosis if diffuse metastasis were already suspected such as a presentation of severe weight loss and an enlarged, palpable, and nodular liver.

Answer B: Anoscopy is used for the evaluation of hemorrhoids in a patient < 40 years of age who presents with bright red blood per rectum in the absence of alarm symptoms. It would not be the most appropriate next step for a patient who presents with unexplained weight loss as it cannot be used to diagnose colorectal cancer.

Answer C: Barium enema is sometimes used to screen for colorectal cancer in conjunction with other tests in asymptomatic patients, but it would not be used to diagnose malignancy in a patient with alarm symptoms such as hematochezia and unexpected weight loss.

Answer E: Ultrasound of the abdomen would be effective in diagnosing conditions such as intraperitoneal bleeding and cholecystitis. There is no evidence of abdominal trauma that would suggest intraperitoneal bleeding in this patient. A positive ultrasound with free fluid would be treated with diagnostic laparoscopy.

Bullet Summary:
If a patient is over the age of 50 or has alarm symptoms of weight loss, abdominal pain, change in bowel habits, or iron-deficiency anemia, the patient should undergo a colonoscopy to rule out colorectal cancer.


Question: Figure A is the lateral radiograph of a 44-year-old male who sustained a fall on his outstretched hand while rollerblading. The patient reports pain localized to the posterior elbow and refuses to attempt elbow extension secondary to pain and swelling. Which of the following is the most likely diagnosis in this patient?

Answer: Triceps rupture

Explanation:
The flake sign, as seen in Figure A is pathognomonic of a triceps tendon rupture.

Tricep tendon ruptures are rare injuries to the elbow extensor mechanism that most commonly occur as a result of forceful elbow contraction. Diagnosis can be made clinically, as patients with complete ruptures are unable to extend the elbow against gravity. An MRI may be useful in the diagnosis in patients whom are too painful to examine or who may have partial tears of the triceps tendon. Surgical repair is indicated in patients with complete rupture or in those with >50% tears and significant weakness.

Yeh et al. review distal triceps ruptures. They report that these injuries are commonly caused by a fall on an outstretched hand or a direct blow. If identifiable on plain radiograph a flake sign or avulsion of the olecranon tip will be appreciated. They conclude that diagnosis may be difficult initially in a painful elbow, however, a combination of plain radiographs and MRI can assist in making the correct diagnosis.

Beazley et al. review distal biceps and triceps injuries. They report that these injuries most commonly occur in middle-aged males as a result of eccentric loading of the tendon. They conclude that patients who undergo early diagnosis and surgical treatment can expect to have excellent outcomes.

Keener et al. review distal tricep tendon injuries. They report that most complete tears are treated surgically in medically fit patients. Partial-thickness tears are managed according to the tear severity, functional demands, and response to conservative treatment. They conclude that anatomic footprint repair of the triceps with optimal tendon to bone healing results in an acceptable functional outcome.

Figure A is the lateral radiograph of an elbow demonstrating a flake sign from the olecranon tip indicative of a triceps rupture.

Incorrect Answers:
Answer A: The patient does not show significant elbow degenerative disease on plain radiographs.
Answer C: Olecranon bursitis is not likely to worsen acutely after a fall, nor are there any other indications of this diagnosis in the present patient.
Answer D: While lateral collateral ligament tears may occur following a fall on an outstretched arm, there is no indication that an elbow dislocation occurred here and based on current radiographs a triceps rupture is more likely.
Answer E: Anconeus avulsions fractures are identified as lateral epicondyle fractures.


Question: A 69-year-old man presents to his primary care physician for a general checkup. Overall he is doing well. Since he retired, he has been working on projects at home and taking time to exercise every day. He eats a balanced diet and has been spending time with his wife every evening. Despite this, the patient claims that he feels less well-rested when he wakes up in the morning. The patient states that he used to sleep 9 hours a night in his youth and felt excellent. Now he sleeps 7 hours a night and doesn’t feel as well rested as he used to. The patient’s wife states that he seems to sleep peacefully. His medical history is significant for hypertension and diabetes for which he takes lisinopril and metformin. His temperature is 98.6°F (37°C), blood pressure is 131/85 mmHg, pulse is 71/min, and respirations are 12/min. His neurological exam is within normal limits. The patient is muscular and has a healthy weight with a pleasant demeanor. He denies feeling fatigued or tired currently. Which of the following physiological changes would most likely be seen in this patient?

Answer: Decreased melatonin

Explanation:
This elderly patient is presenting with sleep that is sufficient but less refreshing than sleep was for him in his past suggesting a diagnosis of normal aging. Melatonin levels naturally decrease as patients age.

Normal aging shortens most phases of sleep. It is normal for melatonin levels to decline during normal aging; however, this change is not responsible for all the symptoms associated with declining quality of sleep. Other changes that occur include decreased REM sleep, decreased stage N3 sleep, and a compensatory increase in stage N2 sleep. Patients will often complain of sleep that is less refreshing than it was in their youth, yet they are still functional and not excessively tired. Treatment is with sleep hygiene though some patients will also benefit from treatment with melatonin supplementation.

Cardinali reviews the role of melatonin in aging. He discusses how natural levels of melatonin decrease in aging animals, which may have implications on the circadian clock. He recommends studies on whether melatonin supplementation may be beneficial to mitigate the effects of aging.

Incorrect Answers:
Answer B: Decreased orexin levels would be seen in patients with narcolepsy, which presents with sudden episodes of falling asleep. This tends to occur in younger patients and is also associated with cataplexy or sudden loss in muscle tone. Treatment of this disorder is with stimulant medications such as modafinil.

Answer C: Increased acetylcholine levels would not be seen in patients as they age and would not explain the changes this patient is experiencing. Rather, acetylcholine levels tend to decline as we age. Drinking caffeinated drinks is associated with increased acetylcholine levels in the brain.

Answer D: Increased dopamine would not be a principle change seen in age-related sleep changes. Higher dopamine levels would increase feelings of being awake as well as alertness. In contrast, decreased dopamine levels can be seen in patients with Parkinson disease, which would present with bradykinesia and a resting tremor.

Answer E: Increased norepinephrine would result in increased wakefulness and potentially insomnia; however, it would not explain the changes seen in normal aging. This chemical is naturally produced during the fight or flight response and can be artificially increased by stimulant drugs such as cocaine.

Bullet Summary:
Normal aging results in a shortening of most phases of sleep as well as decreased melatonin levels and presents with sleep that is subjectively less restful.


Question:
A 25-year-old woman presents to her primary care physician with joint and muscle pain. She has a general aching/pain in her joints that lasts all day. The pain is constant and is not relieved by rest or activity. She also has pain in her hands at times and occasionally notices trouble swallowing when she is eating. She has a medical history of anxiety and is not currently taking any medications. Her temperature is 98.6°F (37°C), blood pressure is 115/72 mmHg, pulse is 74/min, and respirations are 11/min. On physical exam, the patient is a healthy young woman with a sunburn. Her hands are mildly edematous with the findings in Figure A. Laboratory values are below:

Serum:
Na+: 145 mEq/L
K+: 4.4 mEq/L
Cl-: 100 mEq/L
HCO3-: 24 mEq/L
BUN: 9 mg/dL
Glucose: 70 mg/dL
Creatinine: .7 mg/dL
Ca2+: 10 mg/dL
Mg2+: 1.8 mEq/L

Which of the following antibodies is most likely to aid in making the diagnosis in this patient?

Answer: Anti-ribonuleoprotein

Explanation:
This patient is presenting with diffuse muscle/joint pain, Raynaud phenomenon, and dysphagia suggesting a diagnosis of mixed connective tissue disease. Anti-ribonucleoprotein (U1) antibodies are found in this disease.

Mixed connective tissue disease can present with a vast array of symptoms. The most common symptoms are Raynaud phenomenon (vascular hyper-reactivity that presents with burning/pain in the hands where the hands change color from white to blue to red, seen in Figure A), arthralgias, myalgias, dysphagia, and edema of the hands. Anti-U1 ribonucleoprotein antibodies are commonly found in mixed connective tissue disease and are a specific marker. In this disease, there is typically an absence of renal involvement. Treatment involves steroids as well as calcium channel blockers for symptomatic control of Raynaud phenomenon.

Batu et al. review the evidence regarding patients with mixed connective tissue disease. They found that many patients have overlapping symptoms with systemic lupus erythematosus and systemic sclerosis. They recommend studying patients with these mixed characteristics in order to better understand which treatment modalities are effective.

Figure/Illustration A is a clinical photograph showing the blanching of the distal fingers (red box). This finding demonstrates the Raynaud phenomenon during the early phase where the vessels have spasmed.

Incorrect Answers:
Answer A: Anti-dsDNA is a specific marker in systemic lupus erythematosus (SLE). SLE presents with SOAP BRAIN MD - Serositis, Oral ulcers, Arthritis, Photosensitivity, Blood disorders (hemolytic anemia, etc.), Renal involvement, ANA, Immune phenomena (anti-dsDNA, Smith), Neurological symptoms, Malar rash, and Discoid rash. Four of these criteria must be met to suspect a diagnosis of SLE. Treatment is with hydroxychloroquine.

Answer B: Anti-IgG Fc region is representative of rheumatoid factor which is found in rheumatoid arthritis. Rheumatoid arthritis can present with fever, weight loss, and joint pain that worsens in the morning and improves with activity. It is common for the joints of the hands to become deformed due to the disease process. Treatment is with methotrexate.

Answer C: Anti-nuclear antibodies (ANA) are likely positive in this patient; however, they are not more likely to aid in making the diagnosis than anti-ribonucleoprotein antibodies are. ANA are non-specific and can be found in many rheumatological conditions such as MCTD, lupus, and rheumatoid arthritis.

Answer E: Anti-Ro antibodies are found in Sjogren syndrome which presents with dry eyes, dry mouth, dental caries, and dyspareunia. A salivary gland biopsy can be used to confirm the diagnosis. Treatment includes artificial tears, vitamin D supplementation, and pilocarpine or cevimeline.

Bullet Summary:
Mixed connective tissue disease is associated with anti-ribonuleoprotein antibodies and presents with Raynaud phenomenon, arthralgia/arthritis, swollen hands, sclerodactyly, and myositis.


Question:
A 71-year-old man arrives to the emergency room appearing cyanotic and having weak, shallow respirations. He is brought in by his home care nurse, who reports that the patient has a history of myasthenia gravis and frequent urinary tract infections. The patient was in his normal state of health until 5 days ago when he developed a urinary tract infection. He was receiving gentamicin infusions for his infections. This morning, he experienced poor grip strength and progressive difficulty breathing. The patient’s medications include pyridostigmine and aspirin, both of which he takes as prescribed. His temperature is 99.0°F (37.2°C), blood pressure is 128/78 mmHg, pulse is 92/min, and respirations are 28/min with an oxygen saturation of 86% O2 on room air. The patient has gray-blue skin, hypophonia, weak upper extremities, and normal leg strength. An arterial blood gas is drawn with results as shown below:

PO2: 55 mmHg
PCO2: 60 mmHg
pH: 7.30

The patient is intubated. Which of the following is the most appropriate next step in management?

Answer: Plasmapheresis

Explanation:
This patient is presenting with a history of myasthenia gravis, recent exposure to an aminoglycoside, and respiratory failure, suggesting a diagnosis of myasthenic crisis. The most appropriate initial step in management is intubation and plasmapheresis.

Myasthenic crisis is an exacerbation of myasthenia gravis caused by under-dosing myasthenia gravis treatments or precipitated by infection, surgery, and certain medications such as aminoglycosides and beta-blockers. Symptoms include bulbar muscle weakness and type 2 respiratory failure (inadequate alveolar ventilation). The most appropriate initial step in management is to maintain adequate respiratory function by intubation. Plasmapheresis or IVIG is used to remove acetylcholine receptor antibodies from circulation, and steroids are started for long-term therapy. Avoiding risk factors and pre-medication before procedures with acetylcholinesterase inhibitors is important for preventing repeat occurrences.

Rodrigues et al. review the evidence regarding the occurrence of myasthenic crisis in patients with COVID. They discuss how treatment with IVIG and plasma exchange were important in the care of these patients. They recommend also considering whether rituximab and tocilizumab may be effective in these cases.

Incorrect Answers:
Answer A: Atropine can be used in a cholinergic crisis. A cholinergic crisis is an acute exacerbation of muscle weakness due to over-medication with cholinergic anti-cholinesterases. This disease would present with diarrhea, sweating, miosis, bronchoconstriction, and bradycardia. It rarely occurs with proper dosing of pyridostigmine.

Answer B: Edrophonium can be used in the diagnosis of myasthenia gravis. It is a cholinesterase inhibitor. In a positive test, a patient will exhibit temporary resolution of muscle weakness. In this patient’s case, the diagnosis of myasthenia gravis has already been made and he also had a recent exposure to a pharmaceutical known to precipitate myasthenic crisis.

Answer C: Neostigmine is an acetylcholinesterase inhibitor used in the management of myasthenia gravis, but it is contraindicated in the initial treatment of myasthenic crisis. Acetylcholinesterase inhibitors may increase respiratory secretions, which can worsen respiratory failure.

Answer E: Thymectomy is indicated in refractory cases of myasthenia gravis (and for increased risk of thymoma). In an unstable condition such as myasthenic crisis, thymectomy should be deferred. For patients over the age of 60, thymectomy is controversial.

Bullet Summary:
Myasthenic crisis can be precipitated by infection, surgery, and medications (aminoglycosides and beta-blockers) and should be managed with intubation followed by plasmapheresis or IVIG.


Question: A 14-day-old girl is brought to the emergency department for diarrhea. Her mother reports that the patient began having “explosive” diarrhea 6 hours ago. The patient has little interest in feeding since leaving the hospital after her birth and has not yet regained her birth weight. Her immediate postnatal period was otherwise significant for 2 episodes of bilious vomiting that resolved with the temporary use of a nasogastric tube and expulsion of stool during a digital rectal exam. The patient passed meconium on the 3rd day of life. Her temperature is 101.8°F (38.8°C), blood pressure is 58/37 mmHg, pulse is 148/min, and respirations are 38/min. On physical exam, the patient appears to be in moderate distress. She has no dysmorphic features and she has a normal S1/S2 without any murmurs, rubs, or gallops. Her abdomen is firm and distended. A digital rectal exam reveals a tight anal sphincter and precipitates a release of gas and liquid stool. Her abdominal radiograph can be seen in Figure A. Which of the following is the most accurate test to diagnose this patient’s condition?

Answer: Rectal suction biopsy

Explanation:
This neonatal patient presents with bilious vomiting, failure to thrive, colonic distension on an abdominal radiograph, and new fever and tachycardia, which suggests a diagnosis of Hirschsprung disease complicated by enterocolitis. A rectal suction biopsy is the most accurate test to diagnose Hirschsprung disease.

Hirschsprung disease presents in the neonatal period with bilious vomiting, failure to pass meconium in the first 48 hours of life, failure to thrive, and temporary relief of the intestinal obstruction by digital rectal exam. The most severe neonatal complication of Hirschsprung disease is Hirschsprung-associated enterocolitis, which presents in the first few weeks to months of life with explosive diarrhea, fever, and abdominal pain/distension. The most appropriate first step to diagnose Hirschsprung disease is a contrast enema, which may visualize a “transition zone” where the caliber of the intestine switches from the dilated proximal colon to the narrowed aganglionic segment. The most accurate test is a rectal suction biopsy, which will show a lack of ganglion cells. Surgical removal of the aganglionic portion of the colon is preferred management.

Kessman reviews the evidence regarding the diagnosis and treatment of Hirschsprung disease. She discusses how the diagnosis can be made using a rectal suction biopsy. She recommends monitoring patients closely for enterocolitis for years after surgical treatment.

Figure/Illustration A is an abdominal radiograph demonstrating diffuse proximal colonic distension (red circle) with a paucity of air in the rectosigmoid. This finding suggests a diagnosis of Hirschsprung disease.

Incorrect Answers:
Answer A: A contrast enema is both a diagnostic and therapeutic intervention for intussusception. It may also be used in the workup of bilious emesis to help differentiate between Hirschsprung disease and meconium ileus, but it is not the most accurate test.

Answer B: Genetic testing would be used to diagnose cystic fibrosis, which is associated with meconium ileus. Although meconium ileus presents with delayed passage of meconium (> 48 hours of life), meconium ileus is not relieved by a digital rectal exam. Treatment is with irrigation and removal of the meconium.

Answer C: Intraoperative cholangiogram is the gold standard for diagnosing biliary atresia. Biliary atresia presents with jaundice, pale stools or dark urine, and hepatomegaly over the first week to 2 months of life. Treatment is with urgent surgical intervention to prevent liver failure.

Answer E: Upper gastrointestinal series is used to diagnose intestinal malrotation, as the ligament of Treitz can be visualized on the right side of the abdomen. Malrotation may present with bilious vomiting if the malrotation has been complicated by midgut volvulus, but it would not be relieved by digital disimpaction. Treatment is with surgical derotation of the volvulus.

Bullet Summary:
The most accurate test to diagnose Hirschsprung disease is a rectal suction biopsy to demonstrate the absence of ganglion cells.


Question: A 2-day-old boy has an episode of vomiting in the hospital nursery. The vomitus was described as “bright green” without any traces of blood. The patient has urinated several times since he was born but has not passed any stool. He was born at 37 weeks of gestation to a 38-year-old G3P3 woman. The pregnancy was uncomplicated and the patient’s mother refused all prenatal testing. The patient’s 2 older siblings are both healthy. His temperature is 98.6°F (37°C), blood pressure is 67/43 mmHg, pulse is 135/min, and respirations are 34/min. On physical exam, the patient has upslanting palpebral fissures, epicanthal folds, and a single transverse palmar crease. His abdomen is non-tender, firm, and distended. Bowel sounds are hypoactive. Digital rectal exam evacuates a small amount of stool and flatulence. A nasogastric tube is placed to decompress the stomach. The patient’s abdominal radiograph can be seen in Figure A. Which of the following is the most likely diagnosis?

Answer: Hirschsprung disease

Explanation:
This pediatric patient presents with features of Down syndrome (trisomy 21), bilious vomiting, and colonic distention on an abdominal radiograph, which suggests a diagnosis of Hirschsprung disease.

Hirschsprung disease is associated with Down syndrome and presents with bilious vomiting, failure to pass meconium in the first 48 hours of life, and abdominal distension. A digital rectal exam may temporarily relieve the obstruction and lead to the expulsion of gas and stool (the “squirt sign”). Abdominal radiography typically demonstrates signs of distal intestinal obstruction such as proximal dilation and an absence of air in the rectum. Contrast enema may reveal a transition zone between the dilated proximal megacolon and the narrow rectosigmoid colon. A biopsy can confirm the diagnosis. Treatment is with surgical removal of the defective segment of the bowel.

Kessman reviews the evidence regarding the diagnosis and treatment of Hirschsprung disease. She discusses how the diagnosis can be made using a rectal suction biopsy. She recommends monitoring patients closely for enterocolitis for years after surgical treatment.

Figure/Illustration A is an abdominal radiograph that demonstrates colonic distension (red circle). This finding is consistent with a diagnosis of Hirschsprung disease.

Incorrect Answers:
Answer A: Duodenal atresia is associated with Down syndrome (trisomy 21) and may also present in the first 48 hours of life with bilious vomiting. The abdominal radiograph will demonstrate the “double bubble” sign, which reflects air trapping in the stomach and first portion of the duodenum. Treatment is with the surgical opening of the atretic segment.

Answer C: Intestinal malrotation may preset with bilious vomiting in a neonate due to the development of a midgut volvulus. An abdominal radiograph may show the extension of the nasogastric tube into an abnormally positioned duodenum and would not show diffuse colonic distension. Treatment is with surgical derotation of the volvulus.

Answer D: Meconium ileus is associated with cystic fibrosis and also presents with delayed (> 48 hours) passing of meconium. The distal obstruction in these patients will not be temporarily relieved by a digital rectal exam. Contrast enema will demonstrate microcolon involving the entire large bowel. Treatment is with irrigation and removal of the meconium.

Answer E: Pyloric stenosis usually presents in the first 3-6 weeks of life with post-prandial, nonbilious, projectile vomiting and a palpable olive-shaped mass in the epigastrium. This patient is presenting at just 2 days of life and has bilious vomiting. Treatment is with surgical release of the stenosis.

Bullet Summary:
Hirschsprung disease is associated with Down syndrome (trisomy 21) and presents with retention of stool that can be relieved by digital disimpaction, bilious vomiting, and colonic distention on abdominal radiography.


Question: A 62-year-old man arrives at the emergency room complaining of chest pain and difficulty breathing. He reports that the dyspnea started 2 months ago after he had the flu. At first, the difficulty breathing occurred whenever he went up and down 1 flight of stairs, but the dyspnea progressively worsened since then. This morning, he developed chest pain and difficulty breathing while sitting at the kitchen table. The patient’s medical history is significant for hypertension, type 2 diabetes mellitus, and rheumatoid arthritis. His medications include aspirin, lisinopril, metformin, and sulfasalazine. His temperature is 97°F (36.1°C), blood pressure is 130/78 mmHg, pulse is 88/min, and respirations are 14/min with an oxygen saturation of 97% O2 on room air. On physical exam, jugular venous distension during both inspiration and expiration, mild abdominal distention, and 2+ bilateral lower extremity edema is noted. A chest radiograph is obtained and the result is shown in Figure A. Which of the following is the most likely cause of this patient's symptoms?

Answer: Constrictive pericarditis

Explanation:
This patient is presenting with peripheral edema, ascites, elevated jugular venous distension, and pericardial calcifications on chest radiograph, which are all consistent with a diagnosis of constrictive pericarditis.

Constrictive pericarditis is the result of scarring and loss of elasticity of the pericardial sac. Common etiologies include idiopathic, post-viral, post-cardiac surgery, post-radiation, tuberculosis-related, or connective tissue disorder-related. It presents as right heart failure including symptoms such as dyspnea, chest pain relieved by leaning forward, progressive peripheral edema, and ascites. A physical exam will identify an early diastolic pericardial knock, pericardial calcifications on chest radiograph, and jugular venous distension (JVD). Kussmaul sign can also occur where the JVD paradoxically rises during inspiration instead of falling. The diagnosis is supported with echocardiography. Management may require pericardiectomy for severe cases.

Welch and Oh review the evidence regarding the diagnosis and treatment of constrictive pericarditis. They discuss how this disease can be evaluated using a cardiac MRI. They recommend surgical pericardiectomy in many cases.

Figure/Illustration A is a frontal chest radiograph with pericardial calcifications (red circle). These findings are consistent with constrictive pericarditis.

Incorrect Answers:
Answer A: Cardiac tamponade can present similarly to constrictive pericarditis. Hypotension and pulsus paradoxus (a greater than 10 mmHg decrease in the systolic blood pressure during inspiration), will commonly present in patients with cardiac tamponade. A chest radiograph will show an enlarged cardiac silhouette rather than calcifications in some cases. Treatment is with emergent pericardial decompression.

Answer B: Cirrhosis can present with ascites and peripheral edema, but will not have a marked elevation in jugular venous pressure. Cirrhosis is the end-stage result of many hepatic pathologies. Treatment is with the control of sequelae such as hepatic encephalopathy and venous congestion.

Answer D: Pulmonary arterial hypertension, like constrictive pericarditis, can present with exertional dyspnea, chest pain, and peripheral edema if it progresses to right ventricular failure. A chest radiograph may show enlarged central pulmonary arteries and peripheral pulmonary vessels. Treatment is with reduction of pulmonary pressure such as with endothelin inhibitors.

Answer E: Restrictive cardiomyopathy can also present as right heart failure with similar symptoms to constrictive pericarditis. A history of an infiltrative disease (e.g., amyloidosis and sarcoidosis) often favors restrictive cardiomyopathy, as does an audible S3 on a physical exam. Calcification of the pericardium on the chest radiograph is more consistent with constrictive pericarditis.

Bullet Summary:
Constrictive pericarditis presents with symptoms of right heart failure, progressive peripheral edema, ascites, jugular venous distension, pericardial knock, and pericardial calcifications on a chest radiograph.