Cystic fibrosis

Definition

Cystic fibrosis is an inherited disease that affects sodium channels in the body and causes respiratory and digestive problems.

Causes, incidence, and risk factors

Cystic fibrosis affects the mucus and sweat glands of the body and is caused by a defective gene. Thick mucus is formed in the breathing passages of the lungs and this predisposes the person to chronic lung infections.

Many pancreatic enzymes involved in the breakdown and absorption of fats in the intestine are absent, causing malabsorption (inadequate absorption of nutrients from the intestinal tract) and malnutrition.

Most males with cystic fibrosis are infertile. About one in 2500 Caucasians is affected, and 2-5% of Caucasians carry the cystic fibrosis gene.

It is the most common fatal hereditary disorder affecting Caucasians in the United States. It is most common among Caucasians of Northern or Central European descent and is much less common in other ethnic groups. Risk factors include a family history of cystic fibrosis or unexplained infant death.

Symptoms

• No meconium (bowel movements) in first 24 to 48 hours of life
  
• Stools, pale or clay colored, foul smelling, or stools that float
  
• Skin may taste salty (infants)
  
• Recurrent persistent respiratory infections, such as pneumonia or sinusitis
  
• Coughing or wheezing
  
• Weight loss
  
• Diarrhea
  
• Delayed growth
  
• Easy fatigue
  

Signs and tests

• Sweat chloride test
  
• DNA testing
  
• Fecal fat test
  
• Upper GI and small bowel series
  
• Measurement of pancreatic function
  

This disease may also alter the results of the following tests:

• Trypsin and chymotrypsin in stool
  
• Secretin stimulation test
  
• Chest X-ray or CT scan
  
• Pulmonary function tests
  

Treatment

Early recognition of cystic fibrosis and a comprehensive, multidisciplinary treatment program can lengthen survival time and improve quality of life. Specialty clinics for cystic fibrosis can be found in many communities and may be helpful.