Membranous nephropathy in the cat: a clinical and pathological study.

A series of 13 cases of feline membranous nephropathy is presented. Two groups were distinguished clinically; eight cats had the nephrotic syndrome and five others were in renal failure but not nephrotic. The definitive diagnosis was based on histological, immunofluorescence and ultrastructural examinations of renal tissue obtained at renal biopsy or necropsy. Glomerular lesions were classified according to the degree of glomerular change into three distinct groups; mild, moderately severe and advanced. A relationship was established between the mild and moderately severe groups and cats with the nephrotic syndrome, and the advanced group and cats in renal failure. Diuretic therapy was satisfactory in initial control of oedema in the nephrotic cases. Monitoring of previously nephrotic cats for up to three years indicated that the disease is progressive, although in some cases it is sufficiently slow for a cat to live a relatively normal life without continuing treatment. The prognosis for cats presented in renal failure is hopeless.