Cystic fibrosis (CF) is a hereditary disease of the secretory glands, the glands that produce mucus and sweat. Normally, mucus is a moist, slippery substance but, in patients with cystic fibrosis, mucus is thick and sticky.This thick mucus clogs the lungs, air passages, and digestive ducts, resulting in serious respiratory and digestive problems. In addition, CF affects the sinuses and reproductive organs. Cystic fibrosis is a life-threatening disease, but advances in health care have greatly improved the life expectancy of patients with the disease, as well as offering them increased symptom relief.
Causes of CF
Cystic fibrosis is inherited through two defective genes, one from each parent. In the majority of cases, neither parent has the disease. For some patients, the illness is evident from birth. For others, with a milder variation of the disease, symptoms may not be evident until the teens.
Symptoms of CF
As a result of the accumulation of thick mucus in the respiratory tract, patients with CF have serious breathing difficulties. As the lungs and air passages become clogged, it is easier for bacteria to grow, leading to recurring lung infections and eventual lung damage. In the digestive tract, CF causes difficulties with the pancreas, liver and intestines. When essential ducts become clogged with mucus, it is impossible for digestive enzymes to reach their destination and digestion is seriously impaired.
In addition to respiratory symptoms, CF may cause any or all of the following:
- Vitamin deficiency and malnutrition
- Bulky stools, intestinal gas, severe constipation
- Abdominal pain
- Tachycardia and low blood pressure
- Fatigue and weakness
Some of the latter symptoms listed are caused by the abnormally high salt content of the CF patient's sweat. Because the salt is not properly reabsorbed into the body, the patient can easily become dehydrated. Symptoms of CF may ebb and flow, but the disease generally worsens over time.
Patients with cystic fibrosis are at increased risk of developing diabetes, osteopenia or osteoporosis. Female patients are less likely to become pregnant and more likely to spontaneously abort than women without the illness. Ninety-eight percent of men with CF are sterile.
Diagnosis of CF
In the United States, all newborns are screened for CF, using a blood test to check pancreatic function or a genetic test to detect faulty genes. If these tests lead to a suspicion of CF, the patient undergoes a sweat test designed to measure the salt content of the sweat. High salt levels in the sweat are considered definitive.
If a child is diagnosed with CF, other tests may be needed, such as:
- Chest X-ray
- Sinus X-ray
- Lung function test
- Sputum culture
- Further genetic tests
Prenatal screening for CF is also available through amniocentesis or a test of fetal chromosomes. For individuals who have any family history of CF and are contemplating reproduction, genetic counseling is recommended.
Treatment of CF
While there is not presently a cure for CF, the prognosis for patients with this disease has greatly improved in recent decades. As recently as the 1980s, the life expectancy for an infant with CF was somewhere in late childhood or in the teens. Patients diagnosed with CF can currently expect to live into their 40s or 50s. Several treatments are available to make patients more comfortable and to maintain a more normal lifestyle.
Therapeutic treatments for CF include pulmonary rehabilitation, nutritional therapy and specially designed exercise programs. Such therapies may vary according to patient needs.
A great variety of medications can be helpful in providing symptom relief to patients with CF. These may include:
- Mucolytics (to thin mucus)
- Inhaled hypertonic saline
- Non-steroidal anti-inflammatory drugs (NSAIDs)
- Enzyme replacements
A small percentage of CF patients have a particular gene mutation that can be targeted by a particular medication known as ivacaftor. For these patients, administration of this medicine may improve lung function.
Early detection and treatment of cystic fibrosis treatment can increase lifespan and greatly improve quality of life.