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Overview

What Is Cystic Fibrosis?

Cystic fibrosis is a genetic disorder caused by changes in the CFTR gene. These changes make mucus unusually thick and sticky, mainly affecting the lungs and digestive system. The condition is inherited and can affect both children and adults. This cystic fibrosis definition also includes the effects of abnormal salt and water movement in the body’s cells.

Symptoms

Cystic Fibrosis Symptoms

Cystic fibrosis symptoms may begin in infancy, childhood, or adulthood, and they can differ from person to person. Some people mainly have lung symptoms, while others first show digestive problems, poor growth, or reproductive concerns. Not everyone has every symptom, and severity can change over time.

  • A persistent cough may produce thick mucus.
  • Wheezing can occur because narrowed or mucus-filled airways make breathing harder.
  • Frequent lung infections, including pneumonia, may develop.
  • The skin may taste unusually salty because sweat contains extra salt.
  • Poor weight gain or slow growth may occur despite eating normally.
  • Bulky, greasy, or foul-smelling stools may result from poor fat digestion.
  • Constipation or an intestinal blockage may cause abdominal discomfort or swelling.
  • Male infertility may occur because the reproductive ducts may be missing or blocked.

Causes

What Causes Cystic Fibrosis?

Variants in the CFTR gene disrupt the movement of salt and water across cell surfaces. This produces unusually thick mucus and more concentrated sweat, which can affect the lungs, digestive system, and other organs. Cystic fibrosis is inherited; it is not caused by an infection, lifestyle, or anything a parent did during pregnancy.

How Is Cystic Fibrosis Inherited?

Inheritance outcomeApproximate chance per pregnancy
Child inherits altered CFTR copies from both parents and has cystic fibrosis25%
Child inherits one altered CFTR copy and is a carrier50%
Child inherits neither altered CFTR copy25%

Risk Factors

Cystic Fibrosis Risk Factors

  • Having parents who carry CFTR variants increases the chance of inheriting cystic fibrosis.
  • Having a sibling or close relative with cystic fibrosis may indicate an increased inherited risk.
  • Having ancestry from a population in which CFTR variants are more common can increase likelihood, although cystic fibrosis can occur in any ethnic group.

Complications

Cystic Fibrosis Complications

Complications vary between people and are more likely when thick mucus, chronic inflammation, infection, or impaired digestion are not adequately controlled. Regular care can help identify and manage problems early.

  • Bronchiectasis can permanently widen and damage the airways.
  • Recurrent lung infections can cause ongoing inflammation and loss of lung function.
  • Respiratory failure may develop when the lungs can no longer provide enough oxygen or remove carbon dioxide.
  • Coughing blood can occur when damaged airways bleed.
  • Nasal polyps or chronic sinus disease may cause congestion and facial pressure.
  • Pancreatic insufficiency can prevent normal digestion and absorption of nutrients.
  • Cystic-fibrosis-related diabetes can develop when pancreatic damage affects insulin production.
  • Liver disease may occur because thickened bile damages the liver and bile ducts.
  • Low bone density can increase the risk of weak or broken bones.
  • Intestinal blockage can cause abdominal pain, swelling, vomiting, or difficulty passing stool.
  • Fertility problems may affect people with cystic fibrosis, particularly males.

GET MEDICAL ADVICE

Changes that need prompt attention

Seek prompt medical advice for worsening breathing, coughing up blood, severe abdominal pain or swelling, dehydration, or an inability to keep fluids down.

Diagnosis

How Is Cystic Fibrosis Diagnosed?

Many cases are first flagged through newborn blood-spot screening. Others are evaluated because of symptoms, a family history, or an abnormal prenatal or carrier result. Further testing is used to determine whether cystic fibrosis is present.

  • Newborn screening checks a blood sample for markers associated with cystic fibrosis and helps identify babies who need follow-up.
  • A sweat chloride test measures the amount of salt in sweat and is commonly used to help confirm cystic fibrosis.
  • CFTR genetic testing looks for gene variants linked with cystic fibrosis.
  • Additional lung, digestive, or nutritional assessments may be needed to evaluate organ effects and guide care.

Treatment & Management

Cystic Fibrosis Treatment and Management

Cystic fibrosis treatment is individualized and commonly coordinated by a multidisciplinary cystic fibrosis team. Care aims to clear mucus, prevent or treat infection, support nutrition, preserve lung function, and address complications. The plan may change as a person’s symptoms, test results, and treatment options change.

  • Airway-clearance techniques and inhaled medicines help loosen mucus and move it out of the lungs.
  • Antibiotics and other infection treatments are used to prevent or manage bacterial and other respiratory infections.
  • CFTR modulator medicines may correct or improve CFTR protein function for people with eligible gene variants.
  • Pancreatic enzyme replacement and nutrition support help improve digestion, weight gain, and absorption of vitamins.
  • Exercise and pulmonary rehabilitation can support physical fitness, airway clearance, and lung function when advised by the care team.
  • Surgery or lung transplant evaluation may be considered for selected people with advanced disease.

Outlook and Prognosis

Outlook and Prognosis for Cystic Fibrosis

Cystic fibrosis has no cure at present, but outcomes have improved substantially with newborn screening, CFTR modulators, infection prevention, airway clearance, nutritional care, and specialist follow-up. It remains a lifelong condition, but treatment can help many people manage symptoms and protect organ function.

  • The specific CFTR variants can affect symptoms, treatment options, and long-term health.
  • Lung function and how it changes over time are important factors in outlook.
  • The frequency and severity of lung infections can influence long-term health.
  • Nutritional status and the ability to maintain a healthy weight affect overall strength and recovery.
  • Access to treatment and adherence to the individualized care plan can influence outcomes.
  • Involvement of other organs, such as the pancreas, liver, bones, or reproductive system, may affect prognosis.

When Should You See a Doctor

When Should You See a Doctor?

  • Arrange a routine appointment for a persistent cough or wheezing.
  • Repeated chest infections should be assessed by a clinician.
  • Poor growth or difficulty gaining weight warrants medical evaluation.
  • Greasy or bulky stools may indicate a digestive problem that needs assessment.
  • Salty-tasting skin can be a reason to discuss cystic fibrosis testing.
  • An abnormal newborn screen requires prompt follow-up testing.
  • A family history of cystic fibrosis may warrant genetic counseling or diagnostic testing.

SEEK URGENT CARE

Know when symptoms cannot wait

Urgent medical care is needed for severe or rapidly worsening breathing difficulty, blue or gray lips, coughing up more than a small amount of blood, severe dehydration, confusion, or an inability to stay awake.

People with diagnosed cystic fibrosis should follow their individualized action plan and contact their care team promptly when symptoms change from their usual baseline.

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Symptoms

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  • Cystic Fibrosis

    Cough