Bacterial infection in the pathogenesis of variceal bleeding

Variceal bleeding is a life-threatening complication of cirrhosis. Potentia l risk factors include clinical, endoscopic, and haemodynamic factors, but why bleeding occurs unpredictably in individual patients is not known. We p ostulate that bacterial infections in patients with variceal haemorrhage ma y be the critical factor that triggers bleeding. In patients with large var ices and a high wall tension, the release of endotoxin into the systemic ci rculation during episodes of bacterial infection results in a further incre ase in portal pressure through the induction endothelin and possibly vasoco nstrictive cyclo-oxygenase products. The Subsequent. contraction of hepatic stellate cells causes a rise in intrahepatic vascular resistance., further more, endotoxin-induced nitric oxide and postacyclin, and prostacyclin indu ced by endothelin could inhibit platelet aggregation, which may result in a further deterioration of primary haemostasis at the level of varix. We pro pose that the combination of these two effects leads to the onset of varice al haemorrhage.