A 52-year-old man presents with weight loss, steatorrhoea, and migratory polyarthralgia that began three years before his gut symptoms. EGD shows pale yellow shaggy duodenal mucosa, and biopsy of the lamina propria reveals macrophages stuffed with strongly PAS-positive material. Which organism is responsible?

• A Mycobacterium avium complex
• B Tropheryma whipplei ✓
• C Giardia lamblia
• D Histoplasma capsulatum

Explanation

Whipple disease is caused by Tropheryma whipplei, an actinomycete. PAS-positive, diastase-resistant macrophages in the small bowel lamina propria are its histological signature, and migratory seronegative arthritis typically antedates diarrhoea by years. MAC infection in AIDS produces PAS-positive macrophages too, but those bacilli stain positively on Ziehl-Neelsen, whereas T. whipplei is acid-fast negative. Untreated disease can progress to dementia and oculomasticatory myorhythmia; treatment starts with ceftriaxone followed by long-term cotrimoxazole.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.