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Difficulty: MediumGastroenterology and Hepatology

Match each of the following clinical, laboratory, or histopathologic presentations to the most appropriate malabsorptive disorder.

  • Duodenal biopsy reveals villous atrophy, crypt hyperplasia, and an increased number of intraepithelial lymphocytes.Celiac disease
  • Small intestine biopsy demonstrates PAS-positive, diastase-resistant macrophages in the lamina propria.Whipple disease
  • Patient with steatorrhea has significantly decreased fecal elastase but a normal D-xylose absorption test.Chronic pancreatitis
  • Patient experiences osmotic diarrhea after dairy consumption; hydrogen breath test is positive, but small bowel biopsy is entirely normal.Lactase deficiency
  • Patient with chronic diarrhea and megaloblastic anemia following long-term residence in the Caribbean; biopsy shows blunting of villi.Tropical sprue

Answer

Celiac disease matches with villous atrophy/crypt hyperplasia; Whipple disease with PAS-positive macrophages; Chronic pancreatitis with normal D-xylose and low fecal elastase; Lactase deficiency with a positive hydrogen breath test and normal biopsy; and Tropical sprue with megaloblastic anemia after tropical residence.
Each malabsorptive disorder has a distinct pathophysiology that is reflected in specific diagnostic tests. Mucosal diseases (Celiac, Tropical sprue) show physical villous damage on biopsy and cause abnormal D-xylose tests. Pancreatic diseases (Chronic pancreatitis) show abnormal enzyme levels (low fecal elastase) but normal mucosal biopsy and normal D-xylose. Infectious causes like Whipple disease have pathognomonic biopsy findings (PAS-positive macrophages), and brush border enzyme deficiencies (Lactase deficiency) have normal biopsies but positive breath tests.

Step-by-Step Solution

1
Analyze the histological description in the first presentation.
Villous atrophy, crypt hyperplasia, and intraepithelial lymphocytosis are the classic triad for Celiac disease.
These biopsy findings demonstrate the immune-mediated destruction of the intestinal mucosa characteristic of gluten sensitivity.
2
Identify the distinct infectious pathology in the second presentation.
PAS-positive, diastase-resistant macrophages indicate Whipple disease.
These macrophages contain partially destroyed Tropheryma whipplei bacteria, confirming the diagnosis.
3
Evaluate the laboratory results for the third presentation (fecal elastase and D-xylose).
Low fecal elastase indicates pancreatic insufficiency, while normal D-xylose indicates intact intestinal mucosa, matching Chronic pancreatitis.
D-xylose is absorbed without pancreatic enzymes; its normal absorption rules out primary mucosal disease.
4
Connect the specific breath test and symptom trigger in the fourth presentation.
Positive hydrogen breath test with normal histology points to an enzymatic defect, specifically Lactase deficiency.
Unabsorbed lactose is fermented by gut flora, producing hydrogen gas, without physically damaging the bowel wall.
5
Correlate the geographic history and nutritional deficiency in the fifth presentation.
Caribbean residence with villous blunting and megaloblastic anemia (due to folate/B12 deficiency) points to Tropical sprue.
Tropical sprue affects the entire small bowel (unlike celiac, which typically affects the duodenum predominantly) and strongly correlates with extended stays in endemic tropical areas.

Key Concept

Differentiating malabsorption syndromes based on histopathology, geographic history, and specialized diagnostic tests (e.g., D-xylose).
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Topics

Gastroenterology and Hepatology

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