Cystic Fibrosis and the Digestive System
How does cystic fibrosis affect the digestive system?
Children with cystic fibrosis (CF) have a protein in their cells that doesn't work
right. The protein is 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 changes, mucus becomes thickened.
In the digestive system, CF mainly affects the pancreas. The pancreas is an organ
that puts out (secretes) substances that help with digestion and control the body's
levels of blood sugar.
The abnormality in CFTR causes the secretions from the pancreas to become thick. The
thickened secretions can block the ducts within the pancreas. This blockage then causes
a drop in the amount of digestive enzymes the pancreas secretes. Because of this,
a child with CF has trouble 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 type 1
diabetes. About 35 percent of CF patients develop cystic fibrosis-related diabetes
in their 20s, and more than 40 percent develop the disease after age 30.
Because of CF's effects on the digestive system, a child with CF may have these symptoms:
Frequent, bulky, greasy stools
A rare condition in which the end part of the bowels comes out of the anus (rectal
A blockage of the bowel caused by the thick and sticky first bowel movement of a baby
Fat in the stools
Poor weight gain and growth
The child may also have bloating, flatulence, belly pain, and watery diarrhea caused
by an overgrowth of bacteria.
The liver may also be affected. A small number of children may actually develop liver
disease. Symptoms of liver disease may include: