Whipple Disease

Whipple disease is a rare, chronic systemic infection caused by Tropheryma whipplei, a gram-positive actinobacterium that infects macrophages throughout the body. An impaired cell-mediated immune response allows the organism to persist inside macrophages rather than being eliminated. The infected cells become large, foamy macrophages that accumulate in tissues, particularly the lamina propria of the small intestine, where they are periodic-acid–Schiff (PAS) positive. In the small bowel, this accumulation disrupts mucosal absorption and lymphatic transport. The result is malabsorption: chronic diarrhea, greasy or floating stools, abdominal discomfort, weight loss, and deficiencies of fat-soluble vitamins such as vitamins A, D, E, and K. Iron, folate, vitamin B12, and protein-calorie deficiencies may also develop as the illness persists. The organism can disseminate beyond the intestine. Migratory arthralgia may precede gastrointestinal symptoms by years, so a history of unexplained, shifting joint pain can be more informative than the current diarrhea. Neurologic disease may produce cognitive or behavioural change, gait disturbance, abnormal eye movements, or seizures. Cardiac involvement may present as culture-negative endocarditis; ocular inflammation is another sign of dissemination. Oculomasticatory myorhythmia—rhythmic eye movements occurring...