Accurate topographical diagnosis of urinary tract infection in male patients with (111)indium-labelled leukocyte scintigraphy.

Background: Although the clinical diagnosis of urinary tract infection (UTI) is straightforward, the precise localization of the urogenital organ affected by the infection is often difficult to establish.
Methods: To evaluate this, we prospectively studied 20 males with a clinical diagnosis of acute pyelonephritis (APN), acute prostatitis (AP) and febrile UTI (FUTI), as well as seven control females with APN. (111)Indium-labelled leukocyte scintigraphy (ILS) was performed during the febrile episode and repeated when patients were free of symptoms.
Results: ILS showed an abnormal uptake in a urinary organ in every case. All patients with AP showed uptake in the pelvic area. Four male patients presented AP, one of them had uptake in the lumbar area, one in the lumbar and pelvic area, and two in the area of the prostate only. Six out of seven patients with FUTI presented uptake in the pelvic area. All female patients showed kidney uptake. After the clinical resolution of the UTI, no residual uptake was found in any case except for one. Conclusions: These results suggest that ILS is very useful in localizing the affected organ in febrile UTI. Most male patients with a febrile UTI presented a prostatic involvement, suggesting that many cases of APN or FUTI in males may actually be cases of AP not recognized by standard clinical evaluation.