Experimental pyelonephritis: the effect of chronic active pyelonephritis on renal function.

In these experiments, renal function in chronic active pyelonephritis was investigated and the effect of antibiotic treatment and elimination of infection on the gross pathology, histopathology and renal function in animals with chronic pyelonephritis was determined. A severe loss of urine concentrating capacity was demonstrable when the maximum urinary osmolality of a group of animals with pyelonephritis was compared with control animals. Concentrating capacity decreased sharply over the first month but further loss over an eight-month period was minimal. A compensatory increase in the glomerular filtration rate (GFR) in the control, nonchallenged, group occurred after nephrectomy but no comparable compensation in the infected group was found. Antibiotic therapy had a marked effect on the urinary concentrating capacity and the defect in concentrating ability was significantly less in the treated animals during the first 30 days after challenge. Infection again prevented a compensatory increase in the GFR of pyelonephritic animals which was not reversed by antibiotic therapy. Blood urea concentrations in treated and nontreated animals were not significantly different nor did the eradication of infection affect the gross pathologic and histopathologic changes found at autopsy.