Infantile cholestasis--advances in its understanding: new concepts.

Cholestasis is decrease or absence of bile flow into the duodenum. It can be either or in combination pathology of hepatocytes, intrahepatic bile ducts or extrahepatic bile ducts. Hepatocyte with their bile secretory apparatus and tight junction between hepatocytes are of specific importance in this. Bile is formed by several different energy-dependent transport processes. Secretion of bile is a complex metabolic process, which depends upon multiple structural and functional components in the hepatocytes and bile duct cells. The regulation of bile flow is regulated by many hormones. Bile is secreted in bile ducts having pressure of 15-25 cm of water. Rise in pressure in these bile ducts of more than 35 cm of water result suppression of bile flow and jaundice. A rise of conjugated serum bilirubin above the value of 400-500 mumol/L finds an alternate excretory pathway like urine. Various conditions are responsible for infantile cholestasis and can have different outcome of chronic cholestasis. These can be extrahepatic or intrahepatic and acute or chronic. Pathological consequences of infantile cholestasis are mainly because of malabsorption of fat and fat-soluble vitamins and hepatocellular dysfunctions. A battery of tests are required to diagnose the early infantile cholestasis. In the management of cholestasis diet rich in MCT is needed. Further, a high caloric intake up to 200 kcal/day to get adequate weight gain is desirable. Phototherapy, phenobarbitone and rifampicin is helpful in the pruritus of cholestasis by enhancing the excretion of bile. Ursodeoxycholic acid is specifically helpful in the cholestasis. A number of anti-inflammatory and immunosuppressive agents and a new compound, FK 506 has specific role in the management.