The quartan malarial nephrotic syndrome.

A specific relationship between P. malariae and the nephrotic syndrome, originally postulated on epidemiologic evidence, has been substantiated by clinical, pathologic and immunologic observations. It would appear that quartan malaria causes an immune complex nephritis in some individuals that, once established, is sustained by mechanisms not yet fully explained but which may involve an autoimmune process. Evidence to support an immunologic pathogenesis of the renal lesions is provided by the presence of immunoglobulin, complement (C3) and quartan malarial antigen in biopsy specimens studied by immunofluorescence microscopy. In early cases in which some patients respond to treatment, fluorescence is coarsely granular but in late cases in which patients are unresponsive to treatment, fluorescence tends to be diffuse. Renal histology is distinctive and does not conform to any of the categories included in the conventional classification of the nephrotic syndrome in childhood. The basic lesion consists of thickening of glomerular capillary walls, leading to eventual obliteration of capillary lumina, and accompanying mesangial sclerosis leads ultimately to total glomerular sclerosis. A unique feature of electron microscopy is the presence of small lacunae scattered throughout the thickened capillary basement membrane. Histologic grading for severity of lesions shows positive correlation with response to treatment and immunofluorescence appearances. Prognosis is, in general, poor. The large majority of patients do not respond to treatment with prednisolone, azathioprine or cyclophosphamide, and prednisolone administration causes severe hypertension and other serious complications in a high proportion of patients.