Cystic Fibrosis (CF)

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Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention | Organizations

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Definition

Cystic fibrosis (CF) is an inherited disease that causes glands throughout the body to make abnormally thick, sticky mucus. The most frequently affected organs include the lungs and pancreas. The intestines, liver, sweat glands, and reproductive organs also may be affected.

Causes

CF is caused by two defective genes. A child inherits CF by inheriting one defective gene from each parent. Usually the parents do not have the disease but have a defective gene that can be passed on to the their children. These parents are called carriers.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

• Parents who are known carriers of the CF gene
• Siblings with CF
• Parents with CF

Symptoms

The abnormally thick mucus of CF blocks certain organs, causing many of the symptoms of CF.

Symptoms include:

• In infants:
  • Difficulty passing the first stool (meconium)
  • Meconium ileus, or intestinal obstruction (sometimes requires surgery)
• Trouble gaining weight
• Poor growth pattern
• Failure to thrive
• Malnutrition
• Bulky, bad-smelling, floating stools, due to poor digestion of fats
• Coughing and wheezing
• Repeated pneumonia
• Shortness of breath
• Difficulty with exercise
• Salty skin
• Clubbed fingers
• Barrel chest
• Nasal polyps
• Severe, chronic sinusitis
• Pancreatitis
• Insulin-dependent diabetes
• Gallstones
• Liver cirrhosis
• Decreased fertility in females
• No sperm production in males

Diagnosis

The doctor will ask about symptoms and medical history, and perform a physical exam. CF is suspected in a child with classic symptoms, especially if a sibling has CF.

Tests may include:

• Sweat chloride testing
• DNA testing
• Nasal potential difference measurement
• Chest x-rays
• Tests of pancreatic function
• Lung function tests
• Isoproterenol/atropine sweat challenge test
• Newborn screening

Treatment

There is no treatment to cure CF. Treatment is aimed at:

• Preventing severe infections
• Keeping the airways and lungs as clear as possible
• Improving nutritional status

Treatment for CF includes:

• Childhood immunizations
• Enzymes tablets with meals to improve digestion and absorption of nutrients
• Insulin shots if pancreas stops producing it
• High-calorie diet planned by a registered dietician
• Nutritional supplements
• Chest percussion and postural drainage – may help clear mucus from airways
• Medications to keep the airways clear, including:
  • Theophylline
  • Bronchodilators
  • Steroid inhalers
  • DNase
  • Acetylcysteine
  • Nonsteroidal anti-inflammatory drugs
• Drinking lots of fluids, especially in hot weather or when ill
• Surgery – may be required to treat intestinal obstruction
• Oxygen therapy – may be required as the disease progresses
• Lung and liver transplants (possible)

Researchers are exploring gene therapy to slow the progression of CF, or even cure it.

Prevention

If you have the defective genes, there is no way to prevent the development of CF. Adults can be tested to see if they carry the defective gene before having children. Prenatal testing can determine if a baby will have CF.

Organizations

Cystic Fibrosis Foundation
http://www.cff.org/

American Lung Association
http://www.lungusa.org/

American Academy of Pediatrics
http://www.aap.org/

SOURCES:

Nelson Textbook of Pediatrics, 16th ed. W. B. Saunders Company, 2000.

Conn's Current Therapy 2001, 53rd ed. W. B. Saunders Company, 2000.

American Academy of Pediatrics

Cystic Fibrosis Foundation

American Medical Association

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Last reviewed June 2001 by Medical Review Board