Cholestasis

With cholestasis, the flow of bile, the digestive fluid produced by the liver, is impaired at some point between the liver cells and the duodenum (the first segment of the small intestine). Even when bile flow is stopped, the liver continues to process the pigment bilirubin, which escapes into the bloodstream.

The causes of cholestasis are divided into two groups: those originating within the liver and those originating outside the liver. Causes within the liver include acute hepatitis, alcoholic liver disease, primary biliary cirrhosis (inflammation and scarring of the bile ducts (see Fatty Liver, Cirrhosis, and Related Disorders: Primary Biliary Cirrhosis)), the effects of drugs, and the effects of hormonal changes during pregnancy (a condition called cholestasis of pregnancy (see Pregnancy at High-Risk: Fatty Liver of Pregnancy)). Causes outside the liver include a stone in a bile duct, a narrowing (stricture) of a bile duct, cancer of a bile duct, cancer of the pancreas, and inflammation of the pancreas (pancreatitis).

Symptoms

Jaundice, dark urine, pale stools, and generalized itchiness are characteristic symptoms of cholestasis. Jaundice results from excess bilirubin deposited in the skin, and dark urine results from excess bilirubin excreted by the kidney. Retention of bile products in the skin may cause itching, with subsequent scratching and skin damage. Stool may become pale because of a lack of bilirubin in the intestine. The stool may also contain too much fat (a condition called steatorrhea), because bile is not available in the intestine to help digest dietary fat. The lack of bile in the intestine also means that calcium and vitamin D are not properly absorbed. If the cholestasis persists, a lack of these nutrients can cause bone loss. Vitamin K, which is needed for blood clotting, is also poorly absorbed from the intestine, creating a tendency to bleed easily.

Prolonged jaundice from cholestasis produces a muddy skin color and fatty yellow deposits in the skin. The underlying cause of cholestasis determines whether the person has other symptoms, such as abdominal pain, loss of appetite, vomiting, or fever.

Diagnosis

A doctor tries to determine whether the cause is within or outside the liver on the basis of symptoms and the results of a physical examination.

Symptoms that suggest a cause within the liver include loss of appetite, nausea, and vomiting (all of which are symptoms of hepatitis). Heavy alcohol intake or recent use of drugs that can cause cholestasis also suggests a cause within the liver. Small, spiderlike blood vessels visible in the skin, an enlarged spleen, and fluid in the abdominal cavity (ascites) are signs of chronic liver disease.

Features that suggest a cause outside the liver include intermittent pain in the upper right side of the abdomen and sometimes also in the right shoulder or an enlarged gallbladder (which a doctor can feel or imaging studies can detect).

Typically, the blood levels of an enzyme called alkaline phosphatase are very high in people with cholestasis. A blood test that measures the level of bilirubin indicates the severity of the cholestasis but not its cause. An ultrasound or computed tomography (CT) scan or both are almost always done if blood test results are abnormal. If the cause appears to be within the liver, a liver biopsy may be performed and usually establishes the diagnosis. If the cause appears to be blockage of the bile ducts, endoscopy (a procedure involving use of a flexible viewing tube with surgical attachments) is often performed to determine the nature of the blockage.

Treatment

A blockage of the bile ducts can usually be treated with surgery or therapeutic endoscopy. A blockage within the liver may be treated in various ways depending on the cause. If a particular drug is the suspected cause, then the doctor discontinues its use. If acute hepatitis is responsible for the blockage, then the cholestasis and jaundice usually disappear when the hepatitis has run its course. The person is advised to avoid or discontinue using any substance that is toxic to the liver, such as alcohol and certain drugs.

Cholestyramine
taken by mouth, can be used to treat the itchiness. This drug binds with certain bile products in the intestine, so they cannot be reabsorbed to irritate the skin. Unless the liver is severely damaged, taking vitamin K can improve blood clotting. Supplements of calcium and vitamin D are often taken if the cholestasis persists, but they are not very effective in preventing bone loss.