Cystic fibrosis is a life-threatening disorder that causes severe lung damage and nutritional deficiencies. An inherited condition, cystic fibrosis affects the cells that produce mucus, sweat and digestive juices. Normally, these secretions are thin and slippery, but in cystic fibrosis, a defective gene causes the secretions to become thick and sticky. Instead of acting as a lubricant, the secretions plug up tubes, ducts and passageways, especially in the pancreas and lungs. Cystic fibrosis happens most often in white people of northern European ancestry, occurring in about 1 out of 3,000 live births. In the past, most people with cystic fibrosis died in their teens. Improved screening and treatments now allow many people with cystic fibrosis to live into their 50s or even longer.
Complications of Cystic Fibrosis
Many different types of complications can occur with cystic fibrosis. The most common complications affect the respiratory, digestive and reproductive systems.
Respiratory system complications
Bronchiectasis. Cystic fibrosis is one of the leading causes of bronchiectasis, a condition in which damaged airways widen and become flabby and scarred.
Chronic infections. Thick mucus in the lungs and sinuses provide an excellent breeding ground for bacteria. Most people with cystic fibrosis have almost constant infections in their lungs and sinuses.
Collapsed lung. Repeated lung infections damage the lungs, making it more likely for the lung to collapse.
Nasal polyps. Because the lining inside the nose is inflamed and swollen, it's more likely to develop large or multiple polyps — soft, fleshy growths inside your nose.
Respiratory failure. Over time, cystic fibrosis can damage lung tissue so badly that it won't work anymore. Lung function typically worsens gradually, and it eventually can become life-threatening.
Digestive system complications
Nutritional deficiencies. Thick mucus blocks the tubes that carry digestive enzymes from your pancreas to your intestines. Without these enzymes, your body can't absorb protein, fats or the fat-soluble vitamins — A, D, E and K.
Diabetes. The pancreas also produces insulin, which your body needs to use sugar. Cystic fibrosis increases your risk of developing diabetes.
Blocked bile duct. The tube that carries bile from your liver and gallbladder to your small intestine may become blocked and inflamed, leading to liver problems, such as cirrhosis, and sometimes gallstones.
Rectal prolapse. Frequent coughing or straining during constipation can cause internal rectal tissue to protrude outside the anus, particularly in infants.
Intussusception. Children with cystic fibrosis are at higher risk of intussusception, a condition in which a section of the intestines folds in on itself like an accordion. This results in bowel obstruction, an emergency condition.
Reproductive system complications
Many men with cystic fibrosis are infertile because the tube that connects the testes and prostate gland (vas deferens) is either blocked with mucus or missing entirely. Certain fertility treatments and surgical procedures sometimes make it possible for men with cystic fibrosis to become fathers. Although women with cystic fibrosis may be less fertile than other women, it's possible for them to conceive and to have successful pregnancies. Still, pregnancy can worsen the signs and symptoms of cystic fibrosis, so be sure to discuss the possible risks with your doctor.
Osteoporosis. People with cystic fibrosis are at higher risk of developing osteoporosis, a dangerous thinning of bones. This may be linked to the body's inability to absorb vitamin D, which helps build strong bones.
Electrolyte imbalances. Because people with cystic fibrosis have saltier sweat, this can upset the balance of minerals in their blood. Symptoms include increased heart rate, fatigue, weakness and low blood pressure.
Causes of Cystic Fibrosis
In cystic fibrosis, a defective gene alters a protein that regulates the normal movement of salt (sodium chloride) in and out of cells. This results in thick, sticky secretions in the respiratory and digestive tracts, as well as in the reproductive system. It also causes increased salt in sweat.
The affected gene, which is inherited from a child's parents, is a recessive gene. With recessive genes, children need to inherit two copies of the gene, one from each parent, in order to have the disease. If children inherit only one copy, they won't develop cystic fibrosis, but will be carriers and possibly pass the gene to their own children.
Signs & Symptoms of Cystic Fibrosis
Cystic fibrosis signs and symptoms can vary from child to child, depending on the severity of the disease. Even in the same child, symptoms may worsen or improve as time passes. In some children, symptoms begin during infancy. Other people may not begin experiencing symptoms until adolescence or adulthood. One of the first signs of cystic fibrosis is an excessively salty taste to the skin. People with cystic fibrosis tend to have higher than normal amounts of salt in their sweat. Parents often can taste the salt when they kiss their child. Most of the other signs and symptoms of cystic fibrosis affect the respiratory system or the digestive system.
Respiratory signs and symptoms
The thick and sticky mucus associated with cystic fibrosis clogs the tubes that carry air in and out of your lungs. This can cause:
Repeated lung infections
Repeated sinus infections
Digestive signs and symptoms
The thick mucus can also block tubes that carry digestive enzymes from your pancreas to your small intestine. Without these digestive enzymes, your intestines can't fully absorb the nutrients in the food you eat. This can cause:
Foul-smelling, greasy stools
Poor weight gain and growth
Distended abdomen from constipation
Intestinal blockage, particularly in newborns
Diagnosis of Cystic Fibrosis
Newborn screening test. Within the past decade, most states have begun to routinely screen newborns for cystic fibrosis. This test checks a blood sample for a particular component that is commonly elevated in babies who have cystic fibrosis. Other tests are needed to confirm the diagnosis.
Sweat test. This test is necessary to confirm a diagnosis of cystic fibrosis. A sweat-producing chemical is applied to a small area of skin, which is then stimulated with a very weak and painless electric current. The collected sweat is then tested to see if it's saltier than most people's sweat.
Genetic testing. If the sweat test results aren't clear-cut, DNA samples from blood or saliva can be checked for specific mutations on the gene responsible for cystic fibrosis.
Sputum tests. If it appears that you have a lung infection, your doctor may ask you to cough up a sample of the mucus (sputum) so it can be tested to see what types of germs are in it. Your doctor can then choose an antibiotic that works especially well for that specific variety of germ.
Organ function tests. During the course of cystic fibrosis treatment, your doctor may order blood tests that help measure the health of your pancreas and liver.
Damage to your lungs or intestines can be monitored with:
X-rays. This painless test can reveal overinflation of the lungs and clogged bronchial tubes or sinuses.
Computerized tomography (CT). CT scans combine X-ray views taken from many different directions to produce more detailed images of internal structures.
Magnetic resonance imaging (MRI). MRI machines use radio waves and a strong magnetic field to produce very detailed images of internal organs.
Lung function tests
These tests measure:
The size of your lungs
How much air you can breathe in and out
How fast you can breathe in and out
How well your lungs deliver oxygen to your blood
Treatments of Cystic Fibrosis
There is no cure for cystic fibrosis, but treatments can ease symptoms and reduce complications.
Antibiotics. These drugs are used to treat and prevent lung infections. They may be swallowed in pill form, inhaled in a mist or delivered intravenously.
Mucus-thinning drugs. Drugs that reduce the stickiness of your mucus make it easier to cough up the mucus, which improves lung function.
Bronchodilators. Medications such as albuterol — delivered by an inhaler or a nebulizer — help keep your airways open by relaxing the muscles around your bronchial tubes.
People with cystic fibrosis need a way to physically remove thick mucus from their lungs. This is often done by manually clapping with cupped hands on the front and back of the chest — a procedure that's best performed with the person's head over the edge of the bed so that gravity helps clear the secretions.
There also are mechanical devices that help loosen lung mucus. They include:
Chest clapper. This hand-held device can mimic the effect of cupped hands clapping over the ribs.
Inflatable vest. This device vibrates at high frequency to loosen chest mucus.
Breathing devices. Performing specific breathing exercises while exhaling through the device's tube or a mask may also be helpful.
Surgical and other procedures
Feeding tube. Cystic fibrosis interferes with digestion, so you can't absorb nutrients from food very well. Your doctor may suggest using a feeding tube to deliver extra nutrition while you sleep. This tube may be threaded through your nose to your stomach, or surgically implanted.
Lung transplant. Your doctor may suggest lung transplantation if you have severe breathing problems, life-threatening pulmonary complications or increasing resistance to antibiotics used to treat lung infections. Because both lungs are affected by cystic fibrosis, both need to be replaced. Lung transplantation is a major operation and may lead to serious complications, especially post-surgical infections.
Bowel surgery. If you have developed a blockage in your bowel, you may need emergency surgery to remove it — especially if that part of your bowel has died. Intussusception, where a section of bowel has folded in on itself, also may require surgical repair.
Prevention of Cystic Fibrosis
If you or your partner has close relatives who have cystic fibrosis, you both might want to undergo genetic testing before having children of your own. The test, which is performed in a lab on a sample of blood or saliva, can help determine your risk of having a child with cystic fibrosis.
If you're already pregnant and the test shows that your baby may be at risk of cystic fibrosis, your doctor can conduct additional tests on your developing child. The results of these tests can help you decide if you want to continue the pregnancy.
Genetic testing isn't for everyone. Before you decide to be tested, you should talk to a genetic counselor about the psychological impact the test results might carry.
When to seek Medical Advice
Talk to your doctor if your child:
Isn't growing properly
Has a productive cough
Has repeated lung or sinus infections
Has frequent fatty, bad-smelling stools
Seek immediate medical care if your child has difficulty breathing.