The characteristics and hospital course of patients admitted for presumed acute pyelonephritis.

To study the characteristics and hospital courses of patients hospitalized for presumed acute pyelonephritis, the authors analyzed 185 cases. Judged by explicit clinical and laboratory criteria, 54% of the patients definitely had pyelonephritis, 22% probably had pyelonephritis, 9% possibly had pyelonephritis, and 16% did not have pyelonephritis. In pretreatment urine cultures, 79% of patients had a single pathogen and 77% had colony counts of 100,000 or more organisms per ml. Non-Escherichia coli infections and positive blood cultures were the only two independent predictors of the concomitant renal stones or genitourinary tract abnormalities that were found in 29% of patients with pyelonephritis. About 15% of all patients continued to have temperatures greater than or equal to 101 degrees F 48 hours after the initiation of antibiotic therapy, but persistent fever did not correlate with a history of prior urinary tract infection, the presence of resistant pathogens, renal stones, or genitourinary tract abnormalities. The authors conclude that many of these patients did not have pyelonephritis, and that certain characteristics correlate with the presence of underlying anatomic abnormalities.