Cystic Fibrosis

(CF)

by Rosalyn Carson-DeWitt, MD

Definition

Cystic fibrosis (CF) is an inherited disease. It causes a defect in certain cells of the lung and digestive system. The defect makes the cells produce a thick, sticky mucus. This mucus can cause:

  • Blockages in the lungs and airways
  • Problems digesting and absorbing nutrients

Cystic Fibrosis

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CF is a serious life-long condition, but the severity of the illness can vary greatly. The average life expectancy for someone with CF is about 35 years. Although, some with mild forms of CF can live to age 60 or beyond.

Causes

CF is a genetic disorder. A child with CF inherits defective genes from each parent. Parents who have the gene but do not have CF are called carriers.

Risk Factors    TOP

Factors that increase your chance of CF include:

  • Parents who are known carriers of the CF gene
  • Siblings with CF
  • Parents with CF—mostly the mother since men with CF are often sterile

Symptoms    TOP

The abnormally thick mucus of CF blocks certain organs. This causes many of the symptoms of CF.

Symptoms in infants may include:

  • Difficulty passing the first stool
  • Intestinal obstruction, sometimes requiring surgery
  • Salty sweat

Mucus that causes blockages in the lungs may lead to:

  • Coughing and wheezing
  • Shortness of breath
  • Difficulty with exercise
  • Abnormally shaped clubbed finger tips
  • Malformed chest

Mucus can also block the pancreas. This can block enzymes used to help you digest food. This can lead to:

  • Trouble gaining weight
  • Poor growth
  • Failure to thrive
  • Malnutrition
  • Dehydration
  • Bulky, bad-smelling, floating stools, due to poor digestion of fats
  • Diarrhea

Other symptoms may include:

  • Mildly decreased fertility in females
  • Prolapsed rectum
  • Prevention of sperm production in males

Overall, girls are affected more severely than boys.

Diagnosis    TOP

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

CF is often diagnosed by symptoms, family history of CF, or a positive screening test in newborns. The diagnosis may be confirmed with genetic testing. Other lab tests that may be used to confirm CF include:

  • Sweat chloride testing
  • Transepithelial nasal potential difference measurement

Your doctor may need to check your lungs. This may be done to look for symptoms or to determine treatment. Tests may include:

Tests may also be needed to check the pancreas. These tests may be done to assess symptoms or determine treatment.

Treatment    TOP

There is no cure for CF. Treatment is aimed at:

  • Improving the amount of nutrition your body receives
  • Preventing and treating lung infections
  • Keeping the airways and lungs as clear as possible

Treatment for CF includes:

Nutritional Support

Better nutrition will help improve overall health. It will also improve growth and development in children. Children who have returned to normal weight within two years of the diagnosis have fewer coughing episodes and better lung function. Some nutritional steps that may help include:

  • A high-calorie diet planned by a registered dietitian
  • Nutritional supplements, including fat-soluble vitamins
  • Pancreatic enzyme tablets with meals to improve digestion and absorption of nutrients
  • Drinking lots of fluids, especially in hot weather or during illnesses

Managing Lung Infections

Thick mucus in the airways increases the risk of respiratory infections. The infection can also be more severe because of the mucus. Treatment of a current infection often requires antibiotics. Prevention of new infections may be done with:

  • Vaccination
  • Antibiotics

Lung and Airway Support

Medications help keep the airways clear. Most will be delivered through an inhaler or nebulizer. Medications may include:

  • Bronchodilators—to relax muscles and open the airway
  • Steroid inhalers—to decrease swelling and irritation
  • Mucolytic agents—to reduce mucus and help it move out of the lung

Other steps that may help clear mucus from the lungs include:

  • Hypertonic saline is a special type of salt water. A nebulizer machine creates a mist of this saline, which is inhaled. The mist may help thin out the mucus in the lungs.
  • Chest percussion is rhythmic clapping over the chest. They may help clear mucus from airways.

Oxygen therapy may be required as the disease progresses. Ventilation may also be needed.

Other Treatment

Surgery may be required to treat blockages in the intestine. Lung and liver transplants may also be considered.

Support is important for those with CF and their families. Ask you doctor about local support groups or counseling options.

If you or your child is diagnosed with CF, follow your doctor's instructions. Keep all follow-up appointments as advised by your doctor.

Prevention    TOP

If you have the defective genes, there is no way to prevent CF.

Adults can be tested to see if they carry the genes before having children. Prenatal testing can determine if a baby will have CF. The availability of this testing raises many important ethical questions.

RESOURCES:

American Lung Association
http://www.lungusa.org
Cystic Fibrosis Foundation
http://www.cff.org

CANADIAN RESOURCES:

About Kids Health
http://www.aboutkidshealth.ca
SickKids
http://www.sickkids.ca

References:

About cystic fibrosis: what you need to know. Cystic Fibrosis Foundation website. Available at: http://www.cff.org/AboutCF/ . Accessed May 21, 2013.
Cystic fibrosis. American Academy of Pediatrics Healthy Children website. Available at: http://www.healthy... . Updated January 9, 2012. Accessed May 21, 2013.
Cystic Fibrosis. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed . Updated May 2, 2013. Accessed May 21, 2013.
Cystic fibrosis testing. American Medical Association website. Available at: http://www.ama-ass... . Accessed May 21, 2013.
Conn HF, Rakel RE. Conn’s Current Therapy. 54th ed. Philadelphia, PA: WB Saunders Company; 2002: 720-721.
Federico, MJ, Kerby, GS, Deterding, RR, et al. Respiratory Tract & Mediastinum. In Hay W.W., et al, Eds. Current Diagnosis & Treatment: Pediatrics . 20th ed. New York, NY: McGraw-Hill Companies, Inc; 2011.
Kleigman RM, Jensen HB, Behrman RE, Stanton BF. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, PA: Saunders Elsevier; 2007.
4/16/2009 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Lai HJ, Shoff SM, Farrell PM; Wisconsin Cystic Fibrosis Neonatal Screening Group. Recovery of birth weight z score within 2 years of diagnosis is positively associated with pulmonary status at 6 years of age in children with cystic fibrosis. Pediatrics. 2009;123:714-722.
Last reviewed May 2013 by Michael Woods, MD
Last Updated: 5/21/2013
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