Complicated pyelonephritis: unresolved issues.

Complicated pyelonephritis is symptomatic renal infection occurring in an individual with a structurally or functionally abnormal genitourinary tract. It is characterized by a wide spectrum of clinical presentations, a wide variety of infecting organisms, and multiple potential complicating genitourinary abnormalities of variable complexity and severity. Understandably, generalizations about managing this syndrome may be problematic. For many specific abnormalities, limited clinical data exist to assist in developing recommendations for optimal treatment strategies. Recent guidelines and clinical studies addressing selected patient groups clarify and extend our knowledge with respect to some aspects of complicated pyelonephritis.