A 45-year-old male presents with fever, chronic diarrhea, and weight loss. He is found to have multiple pain and swelling of his joints (migratory polyahritis) and generalized lymphadenopathy. Physical examination reveals skin hyperpigmentation. A biopsy from his small intestines reveals the presence of macrophages in the lamina propria that contain PASpositive cytoplasm. The best diagnosis for this individual is
The causes of malabsorption are vast, but in a few cases biopsy specimens of the small intestine may provide clues to a specific diagnosis. Whipple's disease is a systemic disease associated with malabsorption, fever, skin pigmentation, lymphadenopathy, and ahritis. Biopsy of the small intestine typically reveals the lamina propria to be infiltrated by numerous PAS-positive macrophages that contain glycoprotein and rod-shaped bacteria. The organism, Tropheryma whippelii, is a gram-positive actinomycete. The disease responds promptly to broad-spectrum antibiotic therapy. Abetalipoproteinemia is a genetic defect in the synthesis of apolipoprotein B that leads to an inability to synthesize prebetalipoproteins (VLDLs), betalipoproteins (LDLs), and chylomicrons. These individuals have no chylomicrons, VLDLs, or LDLs in their blood. A biopsy of the small intestine reveals the mucosal absorptive cells to be vacuolated by lipid (triglyceride) inclusions, and peripheral smear reveals numerous acanthocytes, which are red blood cells that have numerous irregular spikes on their cell surface. The symptoms of malabsorption may be paially reversed by ingestion of medium-chain triglycerides rather than long-chain triglycerides, because these medium-chain triglycerides are absorbed directly into the poal system and are not incorporated into lipoproteins. Tropical and nontropical (celiac) sprue are both characterized by shoened to absent villi in the small intestines (atrophy). Celiac sprue is a disease of malabsorption related to a sensitivity to gluten, which is found in wheat, oats, barley, and rye. This disease is related to HLA-B8 and to previous infection with type 12 adenovirus. These patients respond to removal of gluten from their diet. Tropical sprue is an acquired disease found in tropical areas, such as the Caribbean, the Far East, and India. It is the result of a chronic bacterial infection. Granulomas in mucosa and submucosa of an intestinal biopsy, if infectious causes have been excluded, are highly suggestive of Crohn's disease. Fibrosis of the lamina propria and submucosa may be seen in patients with systemic sclerosis. Bacterial overgrowth, a result of numerous causes such as the blind loop syndrome, strictures, achlorhydria, or immune deficiencies, may also cause malabsorption. Treatment is with appropriate antibiotics. Reference: Robbins & Cotran Pathologic Basis of Disease, 9edition
Crohn's disease
Hanup disease
Nontropical sprue
Whipple's disease
miscellaneous