Value of ultrasonography, fine needle aspiration, and percutaneous drainage of perinephric abscesses.

With the advent of ultrasonography, perinephric fluid collection can be easily diagnosed and confirmed by fine needle aspiration. In the past these cases sometimes went undiagnosed for several months. We did fine needle aspiration under the guidance of ultrasonography in 16 patients without complications. The aspirant in 12 patients was purulent, confirming the diagnosis of perinephric abscess. In the remaining four the aspirated fluid was nonpurulent and the diagnosis was urinoma or hematoma. Percutaneous drainage was established in five of the 12 patients. The technique is safe and easy to perform, and may be the only treatment necessary in selected cases, thus avoiding unnecessary surgery and prolonged hospitalization.