Total Papillary Necrosis

Irregular medullary cavity Normal Renal Papillary Necrosis – Medullary Form FIGURE 6-36 Schematic of the progressive stages of the papillary form of renal papillary necrosis and their associated radiologic changes seen on intravenous pyelography. Papillary necrosis occurs in one of two forms. In the medullary form, also termed partial papillary necrosis, the inner medulla is affected; however, the papillary tip and fornices remain intact. In the papillary form, also termed total papillary necrosis, the calyceal fornices and entire papillary tip are necrotic. In total papillary necrosis shown here, the lesion is characterized from the outset by necrosis, demarcation, and sequestration of the papillae, which ultimately slough into the pelvis and may be recovered in the urine. In most of these cases, however, the necrotic papillae are not sloughed but are either resorbed or remain in situ, where they becomes calcified or form the nidus of a calculus. In these patients, excretory radiologic examination and computed tomography scanning are diagnostic. Unfortunately, these changes may not be evident until the late stages of RPN, when the papillae already are shrunken and sequestered. In fact, even when the papillae are sloughed out, excretory radiography can be negative. The passage of sloughed papillae is associated with lumbar pain, which is indistinguishable from ureteral colic of any cause and is present in about half of patients. Oliguria occurs in less than 10% of patients. A definitive diagnosis of RPN can be made by finding portions of necrotic papillae in the urine. A deliberate search should be made for papillary fragments in urine collected during or after attacks of colicky pain of all suspected cases, by straining the urine through filter paper or a piece of gauze. The separation and passage of papillary tissue may be associated with hematuria, which is microscopic in some 40% to 45% of patients and gross in 20%. The hematuria can be massive, and occasionally, instances of exsanguinating hemorrhage requiring nephrectomy have been reported. (From Eknoyan and coworkers [8]; with permission.)