Multiorgan microsporidiosis: report of five cases and review.

We describe five cases and review 34 reported cases of multiorgan microsporidiosis. Most of the patients with multiorgan involvement have been adults with AIDS. Organs most commonly infected include the small intestine, urinary tract, biliary tree, and eye; involvement of the respiratory tract, nasal sinuses, and central nervous system is also described but appears to be less frequent. Although patients with multiorgan disease may be asymptomatic, clinical presentation usually relates to the involved organs. Enterocytozoon bieneusi and Septata intestinalis are the most frequently identified species of pathogens. An affinity for certain tissues is observed among different microsporidial species. In all but one case of E. bieneusi infection, infection was limited to intestinal and hepatobiliary tracts, a finding suggestive of local extension. In contrast, the patients infected with S. intestinalis had widespread involvement, suggesting true hematogenous or lymphatic dissemination. Treatment may have to be based on findings regarding which organs and specific microsporidial species are involved. Further investigation of the pathogenic tendencies and route of acquisition of these organisms and the therapeutic agents active against them is needed.