Asymptomatic proteinuria. Clinical significance.

Patients with asymptomatic proteinuria have varied reasons for the proteinuria and travel diverse courses. In the individual with normal renal function and no systemic cause, ie, idiopathic asymptomatic proteinuria, the outlook is generally favorable. Microscopic hematuria probably raises some degree of question about prognosis. The kidney shows normal glomeruli, subtle changes, or an identifiable lesion. The initial approach includes a clinical and laboratory search for systemic disease, repeated urinalyses, quantitative measurements of proteinuria, determination of creatinine clearance, protein electrophoresis where indicated, and intravenous pyelography. The need for regularly scheduled follow-up evaluation is emphasized. Although the initial approach need not include renal biopsy, a decline in creatinine clearance, an increase in proteinuria, or both are indications for biopsy and consideration of drug therapy.