During a newborn examination, you identify a natal tooth in the position of a mandibular central incisor. The tooth is mobile. While natal teeth can be an isolated finding, their presence should prompt a careful examination for features of which of the following syndrome?
A 16-year-old girl presents with mild, intermittent jaundice for the past year. Laboratory studies show: total bilirubin 4.2 mg/dL, direct bilirubin 3.0 mg/dL, normal aminotransferases, and normal alkaline phosphatase. A liver biopsy reveals coarse, dark brown granular pigment in hepatocytes. What is the most likely diagnosis?
A 15-year-old male with a 3-year history of ulcerative colitis has persistently elevated serum alkaline phosphatase and gamma-glutamyl transferase. Magnetic resonance cholangiopancreatography (MRCP) reveals multifocal stricturing and beading of the intra- and extrahepatic bile ducts. A liver biopsy shows features of both bile duct injury and interface hepatitis. In addition to therapy for his inflammatory bowel disease, which therapeutic regimen is specifically indicated for his liver condition?
A 13-year-old presents with acute liver failure, manifesting as jaundice and confusion. Initial laboratory studies are remarkable for a Coombs-negative hemolytic anemia, a serum alkaline phosphatase level that is inappropriately low for the degree of hyperbilirubinemia, and an aspartate aminotransferase level that is significantly higher than the alanine aminotransferase level. Which underlying metabolic disease is the most likely cause of this patient’s acute liver failure?
A 9-month-old infant is brought in for chronic diarrhea, a perioral and perineal rash, and alopecia. The symptoms began shortly after she was weaned from breast milk to a standard infant formula. A deficiency of which micronutrient is the most likely cause of this infant’s symptoms?
A 16-year-old adolescent presents to the urgent care clinic with a 48-hour history of excruciating perianal pain and itching. Examination reveals a tense, bluish, tender nodule at the anal verge, consistent with an acutely thrombosed external hemorrhoid. What is the most appropriate management to provide immediate relief of his severe pain?
A 7-year-old child with a newly diagnosed seizure disorder is started on phenobarbital. Four weeks later, he develops a fever, morbilliform rash, eosinophilia, and elevated transaminases. This presentation is concerning for an idiosyncratic drug-induced liver injury. This reaction is most likely mediated by which of the following mechanisms?
A 3-month-old infant of Navajo descent presents with severe, profuse watery secretory diarrhea since birth, requiring total parenteral nutrition. Electron microscopy of a small bowel biopsy shows enterocytes with abnormal intracellular vesicles containing microvilli. A pathogenic variant in which gene is the most likely cause of this infant’s condition?
A 10-year-old boy presents with a 3-month history of excessive air swallowing, progressive abdominal distention throughout the day, and repetitive belching and flatus. These symptoms are not present during sleep. He has some associated abdominal discomfort but is otherwise well. What is the most likely diagnosis?
A healthy 6-month-old male infant presents with a tender, fluctuant, 1 cm mass in the perianal region consistent with a perianal abscess. He has a low-grade fever of 38.1°C (100.6°F) but is otherwise afebrile, feeding well, and does not appear systemically ill. What is the most appropriate initial management for this infant?
