Cholestatic liver disease: pathophysiology and therapeutic options

Cholestasis results from defective canalicular secretion of bile or obstruction to bile flow distal to the canaliculus. In early primary biliary cirrhosis, bile secretion continues, because of the secretory pressure of bile or because some ductules are not obstructed. With complete cholestasis, a bile acid deficiency occurs in the small intestinal lumen leading to lipid maldigestion and fat-soluble vitamin malabsorption. Bacterial proliferation, bacterial translocation to lymph nodes and endotoxemia may also occur leading to an acute phase reaction. Retention of bile acids in the hepatocyte leads to apoptosis. Accumulation of bile acids in the systemic circulation leads to pruritus, and may contribute to endothelial injury in the lungs and kidney. Early attempts to mimic hepatic excretory function by hemoperfusion over adsorbent columns were unsuccessful for a variety of reasons. Extracorporeal dialysis against albumin offers promise of a realistic albeit partial simulation of hepatic excretory function.