Fever duration in hospitalized acute pyelonephritis patients

To study persistence of fever in treated pyelonephritis with respect to guidelines recommending investigation and modification of therapy after 2 to 3 days of fever.

A retrospective chart review was made of 70 patients hospitalized for febrile pyelonephritis at a community hospital in Canada.

Median duration of fever was 34 hours; persistence of fever at 48 and 72 hours was 26% and 13%, respectively. No patients had complications such as intrarenal or perirenal abscess. Prolonged fever was independently associated with increasing baseline creatinine (P = 0.0001), younger age (P = 0.027), and increasing total leukocyte count (P = 0.026). Results of ultrasonography and intravenous urograms were not predictors of fever duration.

Fever in treated pyelonephritis can take 4 days to resolve, and routine urologic investigation after 2 to 3 days of fever may be unwarranted.