Liver disorders

Question

I often hear about liver disorders in cystic fibrosis. What is this and how do they occur ?

Answer

Thank you for your interesting question. Liver disease does indeed occur in patients with cystic fibrosis. The mildest form of liver disease is the most frequent and this means that there is some abnormality shown in liver function tests (blood tests) in patient who do not have any signs or symptoms of this disease. This occurs in 10-35% of the patients. The worse but fortunately rare form of liver disease is a slow evolution to liver cirrhosis (scar tissue in the liver) which occurs in 5-15% of patients. This sclerosis of the liver can lead to varices in the esophagus with the risk of major esophageal bleeds. The risk to bleeding can be diminished by some medications (beta-blockers), by removing the varices during a gastroscopy or by rerooting the blood via shunts (porto-systemic shunts). Rarely a liver transplant is needed.

The current theory about the origin of liver disease is very complex and is not really fully understood. The disease cystic fibrosis is the consequence of a poor function of a chloride channel, the CFTR protein. The CFTR protein is normally present in the bile ducts. Here it is necessary for the transport of chloride and water into the bile. In the absence of a normally functioning CFTR chloride channel, the bile will be more viscous and remains stuck in the liver, leading to liver damage. This occurs in about 5% of patients.
Other factors that may contribute to liver disease are the composition of the bile or interactions with the immune system or with other predisposing factors. Why some patients have liver disease whereas others do not is not fully understood. The monitoring of liver disease is done by regular blood samples, via ultrasound of the liver and also via newer techniques such as the fibroscan which measures the elasticity of the liver. Sometimes a biopsy is needed. A small piece of liver is taken and studied under the microscope. Patients with onset liver disease can be treated with a water soluble bile supplement or ursodeoxycholic acid. This will make the bile more liquid to prevent worsening of the disease. Also important are an optimal nutritional condition and follow-up and treatment of any possible complication.

More research into the mechanism of liver disease is ongoing, also via better diagnostic tests and via animal models such as the recently developed CF pig. This will hopefully lead to better ways of preventing and treating liver disease.

Kind regards
Dr. P. Witters

14.09.2010