Cystic Fibrosis - Symptoms

The most severe symptoms of CF occur in two body systems: the gastrointestinal (digestive) system and the respiratory tract. CF also affects the sweat glands and the male reproductive organs.

Gastrointestinal System

One of the first symptoms of CF in young babies is meconium ileus (pronounced muh-KO-nee-um ILL-ee-us). Meconium ileus is characterized by a thick, sticky, dark stool. The stool has these features because the mucus it contains is thicker than normal. Meconium ileus is also marked by abdominal swelling and vomiting. The presence of meconium ileus is a strong indication of cystic fibrosis.

A defective CFTR gene also causes damage to the pancreas. The pancreas provides enzymes needed in the digestion of food. Enzymes are chemicals present in all cells that make possible hundreds of different chemical reactions. If these enzymes are not present, necessary chemical reactions may not occur. In the case of CF, the pancreas makes a very thick type of mucus. The mucus blocks openings in the pancreas and enzymes produced by the pancreas cannot get out of the organ. Food passes through the stomach without being digested.

Failure to digest food can produce a number of symptoms. The feces may become bulky, oily, and foul-smelling. The patient may constantly be hungry because food that is eaten is not digested. The patient may not grow to normal size without the nutrients provided by food. Over time, other symptoms that may develop include malnutrition, anemia (see anemias entry), bloating, and loss of appetite.

Respiratory Tract

The most life-threatening symptoms of CF occur in the lungs. The job of the lungs is to take oxygen from the air and deliver it to blood. Blood then takes oxygen to the cells of the body, where it is used to make energy.

The mucus that lines the lungs has a number of functions. One function is to prevent infection of the lungs. The mucus captures bacteria, viruses, fungi, and other agents that might cause disease. It then passes these materials back out of the lungs and into the throat. From there, they can be coughed up or swallowed.

In patients with CF, the mucus in the lungs becomes much thicker. Disease-causing agents are still captured, but they cannot be passed back into the throat very easily. Instead, the thick mucus holds bacteria, viruses, and other organisms in the lining of the lungs. The longer these organisms remain there, the greater the chance they will cause an infection of the lungs.

The presence of organisms in the lungs causes the immune system to become active. The immune system is a network of organs, tissues, cells, and chemicals designed to protect the body against infection by foreign agents. The immune system sends specialized cells to fight the disease-causing organisms trapped in the patient's lungs. These cells cause the lungs to become inflamed and swollen. The inflammation and swelling may close down passageways in the lungs, making it difficult for air to pass in and out of the lungs.

The thick mucus that lines the lungs also makes it more difficult for air to pass through the lungs. Patients may find themselves gasping for breath in order to get enough air. They may also begin to develop the symptoms of emphysema (see emphysema entry).

Sweat Glands

A defective CFTR gene can also affect the formation of sweat. A person with cystic fibrosis has sweat that is much saltier than normal. This problem is usually not serious except during heavy exercise or hot weather. In such cases, patients with CF usually eat more salty foods to make up for the salt lost in their sweat.

Male Reproductive System

Abnormally thick mucus can block the vas deferens in males. The vas deferens are tubes through which sperm passes. If these tubes are blocked, males are not able to produce sperm and are, therefore, infertile (incapable of producing children).