Schistosomiasis and Renal Disease

Schistosoma species--also known as blood flukes and bilharzia--can cause some interesting forms of renal disease. Although this is not so common in the United States, it is a very common public health problem in Africa and Asia.

Chronic Schistosoma mansoni infection in about 10-15% cases is associated with a glomerulonephritis. The etiology is not entirely clear but there is evidence that both schistosomal antigens and antibodies against them can be found in glomeruli from biopsy specimens. Similar to the WHO Classification System for lupus, there is a classification system for schistosomal glomerulopathy which has been set forth by the African Association of Nephrology (AFRAN), and there is an interestingly wide variety of pathologies which can result:

-Class I is a mesangial proliferative GN, the recovery from which is generally good.

-Class II is an exudative GN which is classically observed in patients who are co-infected with both Schistostoma as well as Salmonella (apparently common in some regions).

-Class III is an MPGN.

-Class IV is a proliferative sclerosing GN. Classes III & IV are the most common and most severe form of the disease, which may present as an FSGS-like nephrotic syndrome. Concomitant liver disease (common with Schistosomiasis) and IgA deposition are also suggested to play important pathogenic roles.

-Class V is an AA amyloidosis secondary to chronic inflammation from Schistosomiasis.

Schistosoma hematobium, in contrast, is associated with bladder cancer, particularly in the Middle East. Individuals with Schistosomal-induced bladder cancer are generally treated with radical cystectomy with lymph node dissection, with possible roles for adjuvant or neoadjuvant chemotherapy which are still being determined.