This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': 'A 6-year-old boy presenting with a palpable abdominal mass in the epigastrium. The clinical diagnosis is (There is no bile in vomitus) – \nSelect and explain. \nA. Duodenal Atresia, B. Choledochal cyst, C. Pyloric stenosis, D. Oesophageal Atresia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Diagnosis of congenital hypertrophic pyloric stenosis \n\nHistory of vomiting without bile (nonbilious vomiting).\nPhysical examination -\n\n\nPalpable mass in the epigastrium\nAfter feeding, visible gastric peristaltic wave those progress across the abdomen.\n\nUSG confirm the diagnosis\n\nCriteria → Pyloric thickness > 4 mm or an overall pyloric length > 14 mm.\n\nContrast studies -\n\nShoulder sign\xa0→ A bulge of the pyloric muscle into the antrum.\nDouble tract sign → Parallel streaks of barium in the narrowed channel.\nElongated pyloric channel\n\n\nSo the boy is having pyloric stenosis. The only problem is the age of boy i.e 6 yrs. The hypertrophic pyloric stenosis which we know of makes its clinical presentation in early infancy (3rd to 6th weeks of life)\nBut the problem is solved once you know that there is a similar disease in adults - hypertrophic pyloric stenosis of adults. (Bailey & Love, 22th/e, p 675).', 'role': 'assistant'}]