GI System MCAT Practice Question
A 3-year-old boy from a rural area with limited sanitation presents with acute-onset watery diarrhea, fever, and poor weight gain for 2 weeks following weaning from breast milk. Physical examination reveals sunken eyes, reduced skin turgor, and abdominal distention. Stool studies confirm rotavirus infection. Laboratory findings show hypokalemia, hyponatremia, and elevated fecal osmotic gap. Intestinal biopsy demonstrates flattened villi, crypt hyperplasia, and reduced expression of occludin and claudins. Despite antimicrobial therapy and supportive care, the diarrhea persists. Which of the following best explains the persistent diarrheal symptoms in this patient?
Answer choices
- AReduced epithelial cell turnover from damaged crypts leads to decreased barrier integrity and increased intestinal permeabilityCorrect answer
- BImpaired production of mucus-secreting goblet cells reduces the protective mucus layer against luminal pathogens
- CVillous atrophy prevents adequate nutrient absorption, causing osmotic diarrhea that persists until villous height normalizes
- DCrypt damage impairs secretion of antimicrobial peptides from Paneth cells, promoting bacterial overgrowth and persistent inflammation
- ELoss of enteroendocrine cells in damaged crypts reduces secretion of somatostatin, leading to unregulated intestinal secretion
- FDecreased crypt function triggers compensatory gastric acid hypersecretion, overwhelming intestinal buffering capacity
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