A 30-year-old man with chronic diarrhoea and malabsorption undergoes duodenal biopsy, which shows pear-shaped trophozoites on the surface epithelium without villous invasion. Stool examination reveals cysts. Which additional finding would be expected if the same organism were identified in a patient with common variable immunodeficiency?

• A Granulomas in the lamina propria
• B Nodular lymphoid hyperplasia of the small intestine ✓
• C Acid-fast positive macrophages in the villi
• D Complete absence of goblet cells

Explanation

Giardia duodenalis is the most common cause of parasitic diarrhoea worldwide and causes malabsorption via epithelial injury and disaccharidase deficiency without tissue invasion. In immunoglobulin deficiency states such as common variable immunodeficiency and selective IgA deficiency, giardiasis is frequent and is associated with nodular lymphoid hyperplasia of the small intestine. Acid-fast macrophages suggest Mycobacterium avium complex, and granulomas point toward Crohn disease or tuberculosis.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.