Cystic Fibrosis and the Digestive System

How does CF affect the digestive system?

Children with CF have an abnormality in the function of a cell protein called the cystic fibrosis transmembrane regulator (CFTR). CFTR controls the flow of water and certain salts in and out of the body's cells. As the movement of salt and water in and out of cells is altered, mucus becomes thickened.

In the digestive system, CF mainly affects the pancreas. The pancreas is an organ that secretes substances that aid in digestion and control the levels of blood sugar.

As a result of the abnormality in the function of the cystic fibrosis transmembrane regulator (CFTR), the secretions from the pancreas become thick and lead to an obstruction of the ducts. This obstruction then causes a decrease in the secretion of digestive enzymes from the pancreas. A child with CF has difficulty absorbing fats, some proteins, and fat-soluble vitamins A, D, E, and K.

The problems with the pancreas can become so severe that some of the hormone cells in the pancreas can be destroyed. This may lead to glucose intolerance and insulin-dependent diabetes. About 35 percent of CF patients develop this type of diabetes in their 20s and more than 40 percent develop the disease after 30 years of age.

The symptoms that may be present due to the effects of CF on the digestive system include the following:

• Frequent, bulky, greasy stools

• Rectal prolapse. A condition in which the end part of the bowels comes out of the anus.

• Fat in the stools

• Stomach pain

• Bloody diarrhea

• Poor growth

• Gallstones

The liver may also be affected. A small number of patients may actually develop liver disease. Symptoms of liver disease may include:

• Enlarged liver

• Swollen abdomen

• Yellow color to the skin

• Vomiting of blood