Xanthogranulomatous pyelonephritis

Xanthogranulomatous pyelonephritis: an overview and management guide for clinicians

Xanthogranulomatous pyelonephritis is a rare and chronic form of pyelonephritis. Patients can present with an array of signs and symptoms including flank pain, fever and weight loss. The insidious nature of its clinical presentation means that it can mimic a neoplastic process. Kidney stone disease, diabetes and female gender are the most common associated factors. Early diagnosis can be difficult, but is vital to avoid sequelae such as abscess formation and involvement of surrounding structures. Management requires a multidisciplinary approach. Definitive resolution can only be achieved through nephrectomy. This article provides an overview and guide to diagnosis, investigation and management.

Xanthogranulomatous pyelonephritis complicated by psoas abscess

Xanthogranulomatous pyelonephritis is an unusual variant of chronic pyelonephritis. Xanthogranulomatous pyelonephritis is associated with urinary calculi, urinary tract obstruction, and invasion of the renal parenchyma. Pathologically, xanthogranulomatous pyelonephritis consists of a yellow (xantho) colored infiltrate in renal tissue with granulomatous formation. Xanthogranulomatous pyelonephritis may be distinguished from chronic pyelonephritis by renal size. Typically, the kidneys are enlarged in xanthogranulomatous pyelonephritis and are small/shrunken with chronic pyelonephritis. The diagnosis of xanthogranulomatous pyelonephritis is made by abdominal computed tomography scanning showing the characteristic "bear paw" sign, or findings typical for xanthogranulomatous pyelonephritis, eg, multiple hypo dense areas with ring-enhancing lesions. The definitive treatment for xanthogranulomatous pyelonephritis is antimicrobial therapy and nephrectomy. We present a case of xanthogranulomatous pyelonephritis complicated by psoas abscess.