Urate-induced renal failure

In order to decrease the risk of carcinoid crisis in those patients with symptomatically active tumors, 150-500 micrograms of somatostatin may be given the day before embolotherapy and continued for 3 to 5 days post-treatment [35]. Despite pre-medication, however, carcinoid crisis can occur during the procedure, often manifested by hemodynamic instability. For noncarcinoid or islet cell tumors, treatment of underlying endocrinopathy must be initiated before referral for embolotherapy. In our institution, prophylactic intravenous antibiotic coverage with cefazolin 1 g q8h and metronidazole 500 mg q8h is used routinely during the inpatient stay. In some centers, allopurinol and lactulose are also administered to prevent urate-induced renal failure and post-embolization hepatic encephalopathy. 

In animal models of acute renal failure induced in rats by bilateral nephrectomy and bilateral ureteral ligation, TAC increased, probably due to the accumulation of urate and uremic toxins with scavenging capacity, such as hyppurate (B19, S9). TAC of blood plasma was reduced in a rat endotoxic shock model (rats given i.p. 5 mg/kg lipopolysaccharide) (Cl6). 

In the kidney, the urate crystals (see Fig. 3-62) are usually in the pyramids as diffuse, pale yellow, chalky deposits. They induce some interstitial inflammation, which may develop into a foreign body granuloma similar to that observed in the soft tissue tophi. The urate accumulation may lead to obstruction of the renal papillae with functional impairment, but usually the development of chronic pyelonephritis is responsible for renal failure. 

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