Ultrasound in renal pyogenic infection. Imaging and intervention.

A series of 34 patients with renal or perirenal pyogenic infection (18 with pyonephrosis, 10 with renal abscess and 6 with perirenal abscess) is presented to evaluate diagnosis with ultrasound and treatment with percutaneous ultrasound guided aspiration/drainage. Specific findings, defined as sediment echoes or dispersed internal echoes in a hydronephrotic renal collecting system, were noted in 39 per cent of pyonephrosis cases. Abscesses were mainly round or oval hypoechoic lesions measuring from 2 to 15 cm in diameter. Two abscesses were multilocular and one showed a septum. The appearance suggested tumor in 25 per cent. Because of this non-specificity of ultrasound we recommend diagnostic aspirations and further radiologic and other examinations in difficult cases. Four patients were treated by conservative means only, 13 with percutaneous aspiration or drainage, 9 with a combined drainage procedure and surgery, and 8 surgically. The length of the mean hospital stay was shortest in the group with the percutaneous drainage procedure (PDP) although the difference was not statistically significant. PDP was not effective in 12 per cent and surgery was used in these two cases to ensure cure. Complications occurred more often in the PDP group than in the surgery group but the most serious complication was a post-operative one. The different modes of treatment are discussed. The overall mortality was 5.9 per cent.