An 8-month-old infant with a confirmed diagnosis of cystic fibrosis presents with poor weight gain, abdominal distention, and frequent, bulky, foul-smelling stools. Pancreatic exocrine insufficiency is suspected as the cause of his malabsorption. What is the most appropriate non-invasive screening test to evaluate for pancreatic insufficiency in this infant?
A pediatric resident is examining a 7-year-old boy with a 24-hour history of progressing abdominal pain. The child is lying still and moves cautiously. Which of the following is considered the single most reliable physical finding in the diagnosis of acute appendicitis?
A 10-month-old infant was born to a mother with a known chronic hepatitis C virus infection. The pediatrician wants to determine the infant’s infection status, as maternal antibodies can complicate interpretation. Which of the following is the most reliable method for establishing a diagnosis of hepatitis C virus infection in this infant?
A 12-year-old girl is evaluated for severe fat malabsorption and steatorrhea presenting since birth. She has extremely low plasma cholesterol (< 50 mg/dL), absent deep tendon reflexes, and acanthocytes on her peripheral blood smear. A small bowel biopsy shows enterocytes laden with triglycerides. A pathogenic variant in the gene encoding which protein is responsible for this condition?
An 8-year-old boy admits to swallowing “some” small magnets. A two-view radiograph reveals multiple magnets clumped together in the stomach. The child is asymptomatic. What is the most appropriate management?
A 5-year-old boy presents with a one-week history of jaundice, anorexia, and nausea. He attends a daycare center where several other children have recently been ill with similar symptoms. You suspect acute viral hepatitis. Which serologic marker is most specific for diagnosing an acute hepatitis A virus infection?
A 5-year-old child presents with a 2-month history of watery diarrhea. A 24-hour fasting trial is performed, and the diarrhea persists with little change in stool volume. Stool studies show an osmotic gap of 45 mOsm/kg. Which of the following best describes this type of diarrhea?
A 10-year-old boy with a history of asthma and food allergies is diagnosed with Eosinophilic Esophagitis (EoE) after an endoscopy for dysphagia revealed ≥ 15 eosinophils/hpf. He is started on a high-dose proton pump inhibitor (PPI), and a follow-up endoscopy shows significant histologic improvement. What is the most likely mechanism explaining his response to PPI therapy?
A 6-year-old boy presents with high fever and dysentery. His mother reports he passed more than 15 small, bloody stools in the last 24 hours. He appears toxic and requires hospitalization. Given the high suspicion for severe shigellosis in an area with known antibiotic resistance, the physician decides on empiric parenteral therapy. Which parenteral antibiotic is a recommended first-line agent?
A 12-year-old boy on long-term, high-dose naproxen for juvenile idiopathic arthritis develops epigastric pain and has one episode of hematemesis. An endoscopy reveals multiple erosions and a 1 cm ulcer in the gastric antrum. What is the primary mechanism of his ulcer formation?
