Primary biliary cirrhosis is the gradual destruction of the biliary system for unknown reasons.

It represents 15-20% of all cirrhosis

yes

It is a progressive disease characterized by destruction of small bile ducts

Increased levels of bilirubin in the urine may be due to: * Biliary strictures * Cirrhosis * Gallstones in the biliary tract * Hepatitis with associated biliary obstruction * Surgical trauma affecting the biliary tract * Tumors of the liver or gall bladder