Renal Biopsy in Recurrent Urinary Tract Infection

Abstract

There are still many gaps in our understanding of the natural history of pyelonephritis and its relation to recurrent urinary tract infection. Increasing attention is turning, therefore, to the problem of urinary tract infection in childhood, with its possible implications for chronic renal and vascular disease in early adult life. Unfortunately, however, neither clinical features, urine analysis, nor radiographic findings are always sufficient to establish the diagnosis of pyelonephritis beyond question.Recent studies by colony counting techniques 1,2 have done much to emphasize the potential seriousness of bacteriuria unaccompanied by pyuria and to distinguish between significant bacteriuria and mere bacterial contamination of the urine. However, neither colony counting techniques 1,2 nor the newer provocative pyrogen test3,4 can distinguish between infections located in the kidney and those arising elsewhere in the urinary tract, so that direct evidence obtained by renal biopsy should contribute to our overall picture of the urinary infection problem. Information so far is meager concerning the early pathogenesis of pyelonephritis in man as well as the renal biopsy findings in urinary tract infections in childhood.Although it is one of the oldest urological axioms that urinary stasis predisposes to infection, in most reported studies of pye¬ lonephritis in adult patients a thorough radiographic and urological assessment of any accompanying anatomical or physiological abnormalities of the urinary tract is seldom reported in detail. Gross anatomical abnor¬ malities causing obvious mechanical obstruc¬ tion have long been recognized and are usually evidenced by clinical features and by intravenous pyelography. Such routine screening methods, however, will often miss functional abnormalities responsible for uri¬ nary stasis 5·6 or congenital dilatations not caused by obstruction to urine flow.7"9 The