Ultrasound detection of focal bacterial nephritis (lobar nephronia) and its evolution into a renal abscess

A case of acute focal bacterial nephritis (lobar nephronia) which evolved into a renal abscess is reported. This case is unusual for 2 reasons: the focal nephritis was isoechoic (not previously reported), and it progressed to an abscess despite antibiotic therapy. Ultrasound initially detected the focal nephritis and later confirmed its progression to an abscess. Successful treatment was obtained with sonographically guided percutaneous catheter drainage in conjunction with systemic antibiotics.