Asymptomatic Group-B Streptococcal Pyelonephritis: An Unusual Cause of Acute Renal Failure

Dr. S.N. Heyman, Department of Medicine, Hadassah University Hospital, Mt. Scopus, PO Box 24035, IL-91240 Jerusalem (Israel) Dear Sir, Acute renal failure may complicate urinary tract infection by means of urinary tract obstruction or extensive tissue destruction. Such conditions characteristically lead to a dramatic clinical course, especially in patients with a single functioning native or transplanted kidney [1]. We report an elderly patient who developed acute on chronic kidney failure as a result of an asymptomatic pyelonephritis caused by group B streptococcus. Routine blood tests were undertaken in an 81-year-old hypertensive woman with known impaired renal function. After discontinuation of a prolonged treatment with enalapril, plasma creatinine rose unexpectedly from 2 to 3.5 mg/dl over 3 weeks without an apparent cause (fig. 1). The patient was asymptomatic, afebrile and well hydrated, and physical examination was unremarkable. Urinalysis disclosed an unusually heavy, cream-colored sediment, exceeding 25% of the urine volume. It consisted of numerous WBCs, white cell casts and bacteria. Group B streptococci were grown in repeated urine cultures. Wright stain of the urinary sediment revealed predominance of polymorphonuclear cells, 6% eosinophils and 3% mononuclear and plasma cells. Small echogenic kidneys (long axis diameter of 7.6 and 8.3 cm) were demonstrated by sonography, without evident calculi, abscesses, papillay necrosis or urinary tract obstruction. A prolonged course of amoxicillin resulted in a rapid clearing of the urine and a prompt return of kidney function towards baseline values. This patient presented with acute renal failure, induced by asymptomatic, group B Amoxicillin Enalapril i3⁄8 3 ε 1⁄8 2 1 < o < 7⁄8 < O