Basic Guide to Cystic Fibrosis Symptoms

Early and Advanced Signs of CF, a Progressive and Genetic Disease

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Usually, cystic fibrosis symptoms increase as the disease progresses. The condition, which is caused by a defective gene, causes a thick layer of mucus to build up in the lungs (clogging airways and leading to infections, lung damage, and respiratory failure), pancreas (preventing the body from breaking down food properly to absorb nutrients), and other organs.

The defective gene does not allow the body to transfer water and salt to and from cells, causing secretions (normally thin and watery in healthy people versus very thick and sticky in people with CF). The thick secretions are what clog organs and prevent the smooth operation of the body. 

Early Symptoms of Cystic Fibrosis 

Most of the time, newborns with cystic fibrosis (CF) look just like healthy babies because the disease does not cause any visible abnormalities in the early stages. About 20% of the time, babies with CF will have a serious intestinal obstruction at birth called a meconium ileus. This type of obstruction rarely occurs unless a baby has CF, so if it occurs it is usually considered the first symptom of the disease.

Common Cystic Fibrosis Symptoms

If cystic fibrosis is not detected at birth, other symptoms will usually begin to appear in the first year or two of life, such as:

  • Poor Weight Gain. Blockages in the pancreas and intestinal glands prevent the digestive system from working properly. Foods that are eaten pass through the body without many nutrients being absorbed, resulting in poor growth. If a baby has not regained his or her birth weight by 4-6 weeks of age or shows an ongoing pattern of poor growth, the doctor may begin to suspect CF.
  • Huge Appetite. Because the nutrients are not absorbed from foods, the brain tries to meet the body’s energy requirement by sending hunger signals. People with cystic fibrosis will often have voracious appetites and can consume tremendous amounts of food without resulting weight gain.
  • Bulky, Oily, Foul Smelling Bowel Movements. The poorly functioning digestive system has particular trouble digesting fats and proteins. Much of what would normally be absorbed by a healthy digestive system is excreted by the bowels, resulting in the abnormal bowel movements that often occur in patients with CF.
  • Frequent Cough and Respiratory Infections. Coughing, difficulty breathing, and frequent respiratory infections are often the first symptoms recognized by parents of children with CF. 
  • Salty Skin. The genetic defect that causes cystic fibrosis interferes with the body’s ability to move salt in and out of cells. The salt that cannot be absorbed is excreted through the skin by the sweat glands, resulting in the telltale sign of salty tasting sweat. Sometimes, there may even be visible salt deposits on the skin. Salt excretion by the sweat glands is the basis of the most common test used to diagnose cystic fibrosis.

    Advanced Signs and Complications of CF

    Advanced symptoms of cystic fibrosis are not usually symptoms of the disease itself, but symptoms of the damage that CF causes over time. By the time these conditions appear, most people already know that they have cystic fibrosis and have been living with the disease for quite some time. The following complications are advanced symptoms of CF:

    • Delayed Puberty. Delayed puberty is sometimes seen in girls with cystic fibrosis as a result of poor nutrition.
    • Infertility. Most males with cystic fibrosis are infertile because of secretions blocking the passage of sperm. Women may experience infertility as a result of thick cervical mucus blocking the entry of sperm into the reproductive organs.
    • Diabetes. Over time, the damage done to the pancreas by cystic fibrosis causes it to stop producing enough insulin. About 15% of the people with cystic fibrosis that reach adulthood will develop insulin dependent diabetes.
    • Liver Disease. Blockage of bile ducts in the liver causes scarring and liver damage in about 5% of cystic fibrosis patients. If liver damage does occur, it is usually seen in adults.
    • Gallbladder Disease. The gallbladder stores a substance called bile that is created by the liver and aids in the digestion of fat. In many people with cystic fibrosis, the bile is thick and cannot pass through the bile duct to leave the gallbladder. Most of the time this does not produce symptoms, but about 10% of cystic fibrosis will develop gallstones requiring surgery.
    • Pancreatitis. When bile leaves the gallbladder, it travels into the small intestine through the common bile duct that is shared with the pancreas. If a gallstone leaves the gallbladder and gets stuck in the common bile duct, pancreatic secretions can’t get through. This causes a very painful swelling and irritation of the pancreas known as pancreatitis, which requires surgical intervention.


    Cystic Fibrosis Foundation. About Cystic Fibrosis. 10 April 2016