Chronic splenomegaly in Nairobi, Kenya. I. Epidemiology, malarial antibody and immunoglobulin levels.

Chronic splenomegaly in 131 Kenyan patients was investigated at Kenyatta National Hospital, Nairobi. Patients were allocated to diagnostic groups on the basis of clinical, haematological, parasitological, histological, radiological and endoscopic data. The major diagnostic groups were hyper-reactive malarial splenomegaly, our preferred name for tropical splenomegaly syndrome, (31%), hepatosplenic schistosomiasis (18%), visceral leishmaniasis (5%) and "indeterminate splenomegaly", where no diagnosis could be reached (12%). Another 20% of patients were suffering from various non-schistosomal forms of portal hypertension. A number of specific and rarer causes accounted for the rest of the cases. The tribal and geographical distribution of patients with chronic splenomegaly was compared with the pattern of general medical admissions. Splenomegaly was more frequent than expected in Kamba and Luo patients. Hyper-reactive malarial splenomegaly and hepatosplenic schistosomiasis were common in both groups, whereas visceral leishmaniasis was almost restricted to the Kamba and indeterminate splenomegaly was especially prevalent in the Luo. Malarial antibody and immunoglobulin levels differed significantly between the various diagnostic categories of patients and controls. Malarial serology can be diagnostically useful for chronic splenomegaly, provided results are interpreted in their geographical context.