Figure 638

Diabetes mellitus is the most common condition associated with papillary necrosis. The occurrence of capillary necrosis is likely more common than is generally appreciated, because pyelography (the best diagnostic tool for detection of papillary necrosis) is avoided in these patients because of dye-induced nephrotoxicity. When sought, papillary necrosis has been reported in as many as 25% of cases. Analgesic nephropathy accounts for 15% to 25% of papillary necrosis in the United States but accounts for as much as 70% of cases in countries in which analgesic abuse is common. Papillary necrosis also has been reported in patients receiving non-steroidal anti-inflammatory drugs.

Sickle hemoglobinopathy is another common cause of papillary necrosis, which, when sought by intravenous pyelography, is detected in well over half of cases.

Infection is usually but not invariably a concomitant finding in most cases of RPN. In fact, with few exceptions, most patients with RPN ultimately develop a urinary tract infection, which represents a complication of papillary necrosis: that is, the infection develops after the primary underlying disease has initiated local injury to the renal medulla, with foci of impaired blood flow and poor tubular drainage. Infection contributes significantly to the symptomatology of RPN, because fever and chills are the presenting symptoms in two thirds of patients and a positive urine culture is obtained in 70%. However, RPN is not an extension of severe pyelonephritis. In most patients with florid acute pyelonephritis, RPN does not occur.

Spectrum of Renal Papillary Necrosis

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