QBDOTW: A 19-month-old Male Brought to ED
Welcome back to MedSmarter’s USMLE Style Question of the Week. Here’s the breakdown of a high-yield Pediatrics GI question for those preparing for your USMLE Step 1. As always you want to begin with reading the last sentence of the vignette first to get an understanding of what the question is asking for.
Question Break Down of the Week:
A 19-month-old child is brought to the emergency department after his parents found blood in his stool. They state that he has not had any acute distress, although he now displays some tenderness to abdominal pressure. Other than this tenderness, there are no significant findings on physical examination. After performing radionuclide imaging using technetium 99m, the doctor makes a diagnosis and recommends surgery to correct the problem. What is the probable source of this child’s condition?
A) Blockage of the intestine due to folding of the distal ileum into the proximal colon
B) Breakdown of the stomach mucosal barrier with the erosion of the underlying mucosa
C) Damage to the intestinal epithelium due to ingestion of coins
D) Ectopic gastric epithelium in a persistent omphalomesenteric duct
E) Incomplete bowel rotation resulting in obstruction of the superior mesenteric artery
The correct answer choice is D: The child was diagnosed with a Meckel’s diverticulum, which describes the persistence of part of the omphalomesenteric duct after birth. Meckel’s diverticulum is usually found in the mid to distal ileum and may end blindly or connect to the umbilicus. It is described by the “rule of 2’s:” it is about 2 inches long, 2 feet from the ileocecal valve, occurs in about 2% of the population, is often presents before age 2 years, and may contain 2 types of mucosa (gastric or pancreatic). Ectopic gastric epithelium can cause ulcers and bleeding but does not generally cause severe pain unless inflammation occurs. Technetium 99m is absorbed preferentially by the gastric mucosa and thus may be used to detect ectopic gastric mucosa in the diverticulum.
Did you think the answer was different?
Did you think that the correct answer choice was other than D? You can view this video for a deeper discussion of why A, B, C, and E were not the correct answer choices.
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