[Clinical study of sonography and percutaneous nephrostomy in pyonephrosis]

Sonography and percutaneous nephrostomy (PNS) were performed on 16 patients with pyonephrosis and the following results were obtained. Sonography revealed a dilated collecting system in all cases within which, however, neither debris nor gas was observed in any case, the pelvocaliceal system appeared hypoechoic in 2 cases and anechoic in 14 cases. From the clinical symptoms and the dilated collecting system demonstrated by sonography, pyonephrosis was diagnosed in 14 cases. The purulent fluid aspirated from the collecting system confirmed the diagnosis in all cases. The clinical condition was stabilized by PNS and antibacterial therapy in all cases. However, in 5 of the patients with pyrexia for more than 6 days before PNS, sepsis developed in 3 cases and pyrexia continued for more than 3 days after the treatment in 4 cases. The affected 11 kidneys showing recovery of renal function following PNS were all salvaged by elective surgery. These findings suggest that prompt diagnosis by needle aspiration is necessary, even in the absence of any sonographically characteristic findings, whenever pyonephrosis is suspected. Our experience suggests that PNS is a useful therapeutic procedure for pyonephrosis.