How does cystic fibrosis increase the risk of respiratory infections such as bronchitis and pneumonia?

Cystic fibrosis (CF) is a genetic disease that affects the lungs, digestive system, and other organs. It develops when the protein that produces mucus does not function as usual. This results in thick, sticky mucus that can damage or obstruct organs.

There is currentlyno cure, but treatments can help manage the condition, relieve the symptoms, and reduce the risk of complications. This improves a person’s life expectancy and quality of life.

This article explores the causes and symptoms of CF. It also looks at the treatments, risk factors, outlook, and how doctors diagnose the condition.

What is CF?

CF is a genetic disease thatmainly affectsthe lungs and digestive system. It can also cause complications, such as liver disease and diabetes.

People with CF have agenetic mutationin a gene called the cystic fibrosis transmembrane conductance regulator (CFTR). This gene controls the CFTR protein.

The protein is present inevery organthat creates mucus. It is also present in other organs and tissues, including those in the:

• lungs
• pancreas
• intestines
• liver
• heart
• immune system
• sweat glands

The genetic mutation mean that the CFTR protein does not function as it would in a healthy body. This malfunctioning causes the body to produce mucus that is thicker and stickier than usual. It can block the airways, causing breathing difficulties and severe lung infections.

The genetic mutation may also interfere with pancreatic function by preventing enzymes from breaking down food effectively. This can cause digestive problems that may lead to limited growth and malnutrition.

CF is a chronic condition with potentially life threatening complications. However, treatments can improve the quality and duration of life.

Symptoms

CFmost commonlyaffects the lungs, causing respiratory symptoms, such as:

• wheezing
• shortness of breath
• persistent coughing, which may bring up blood or mucus
• other breathing difficulties

Also, in people with CF, the mucus that obstructs lung function creates optimal living conditions for pathogens. As a result, a person has an increased risk of lung infections, such as bronchitis and pneumonia.

CF symptoms can vary from person to person, depending on the affected organs. Some other possible symptoms and complications are:

• frequent sinus infections
• gastrointestinal issues, such as:
  • abdominal pain
  • constipation
  • diarrhea
  • greasy, foul-smelling stool
• nasal polyps, which are small, fleshy growths inside the nose
• salty skin and sweat
• night sweats
• fever
• joint and muscle pain
• low body weight
• limited growth or weight gain in children
• delayed puberty
• male infertility
• clubbed fingers and toes, due to a lack of oxygen to the extremities

The obstruction of the pancreas that can lead to malnutrition and limited growth is also linked to anincreased riskof diabetes and osteoporosis.

Treatment

Treatments can help manage symptoms and improve the quality of life. The best combination of approaches depends on a person’s symptoms. Below, we describe some treatment options.

Airway clearance

It is crucial to loosen and clear mucus from the lungs to ease breathing and minimize the risk of infections. Airway clearance techniques can help.

As a2019 reviewpointed out, people with CF may use these techniques daily. The review did not find any particular method more effective than another.

Some airway clearance techniques that a person might try include:

• Postural drainage: This involves getting into certain positions so that gravity helps move mucus into the center of the airways, where it can be dislodged more easily.
• Percussion: Clapping cupped hands against the chest can help loosen mucus.
• Vibration: This involves exhaling while a therapist uses their hands to make light, repetitive movements against the chest. This vibrations help loosen the mucus.
• Breathing techniques: Specific breathing exercises can help loosen and dislodge mucus.
• Positive expiratory pressure: This involves using a device that supports airflow and helps move mucus out of the airways.

Medications

Certain medications can help alleviate CF symptoms and otherwise manage the condition. Examples include:

• Bronchodilators: These drugs help relax the muscles around the lungs, giving the airways more room to expand. Some also help clear mucus from the lungs.
• Hypertonic saline: Sterilized salt water can help clear mucus and improve lung function in people over 6 years of age.
• Ibuprofen: High doses may help slow down the decline of lung function.
• Dornase alfa: People with CF can inhale this drug to support mucus clearance.
• Antibiotics: People with CF may take antibiotics, orally or with an IV, to treat bacterial lung infections. Doctorsdo not usuallyrecommend inhaled antibiotics to treat CF exacerbations due to bacterial infections.

Infection management

If an infection is bacterial, antibiotics can help treat it. Also, a person may be able toreduce their riskby:

• closely following their treatment plan
• getting any vaccinations that a doctor recommends, such as a yearly flu shot and a pneumococcal vaccine
• washing their hands regularly with soap and water, especially in the following situations:
  • before eating
  • before taking medications or using any breathing equipment
  • after using the restroom

Other treatment methods

Below are some other ways of managing CF:

Vascular access devices

These implanted devices deliver medication directly into the bloodstream, and they may be suitable for people who require long-term access to IV treatment. Having one can make managing CF more efficient and less intrusive.

The device may consist of a long, thin tube inserted into a vein in the arm and secured to the skin with stitches or adhesive. Another option is a port, a device that a surgeon implants under the skin. The port connects to an IV tube when a person needs IV medication.

CFTCR modulators

These drugswork to correctthe function of the CFTR protein.

Two approved CFTR modulators are ivacaftor (Kalydeco) and lumacaftor/ivacaftor (Orkambi). Kalydeco may be suitable for children 6 years and older who have an additional eight CF gene mutations. Orkambi may be suitable for those between 6 and 11 years old with a F508del genetic mutation.

Nutritional therapy for digestive symptoms

CF can affect digestive function and nutrient absorption, so receiving professional dietary guidance is key. A registered dietitian may recommend:

• Having a high fat diet: As2021 researchhas found, having a high fat diet and taking fat-soluble vitamin supplements may help counteract nutrient malabsorption.
• Increasing the calorie intake: This can help prevent unwanted weight loss. The authors of the 2021 research report that female adults may need to consume 2,500–3,000 calories per day and male adults may need 3,000–3,700 calories per day.
• Increasing the salt intake: People with CF may need to take in more salt to counteract sweating regularly due to exercise or living in a hot climate.
• Taking pancreatic enzyme supplements: Around 80–90% of people with CF may need pancreatic enzyme supplements. This is because CF can prevent the pancreas from making the enzymes necessary to break down food. The supplements can help with:
  • maintaining a healthy weight
  • preventing malnutrition and vitamin deficiencies
  • improving bowel movements

Causes

The CFTR gene contains codes for producing a protein that controls the flow of salt and water across cell membranes. In someone with CF, this gene does not function as usual, leading to low levels of salt and water outside the cells. The result is unusually thick, sticky mucus.

If a person has only one copy of the malfunctioning gene, they do not develop CF but they “carry” it. For a person to develop CF, both biological parents must carry the malfunctioning gene.

According to the National Organization for Rare Disorders, if two carriers have a child, there is a:

• 25% chance with each pregnancy that the child will have CF
• 50% chance with each pregnancy that the child will be a carrier but will not have it
• 25% chance that the child will not be a carrier and will not have CF

Over10 million peoplein the United States are likely to be carriers of CF, and many are unaware.

Risk factors

Risk factorsfor CF include:

• Genetic factors: People are more likely to have CF if one or both biological parents is a carrier or has the condition. The risk also increases if people have a sibling, half-sibling, or cousin with CF.
• Race and ethnicity: CF most commonly affects people of Northern European heritage. It is less common among people who are:
  • Hispanic
  • African American
  • Asian American

CF test and diagnosis

Some symptoms of CF may appear shortly after birth. But the symptoms of mild cases may not present until adulthood. More than 1,000 people in the U.S. receive a CF diagnosis each year, with 75% receiving a diagnosis by the age of 2 years.

All newbornsin the U.S. undergo screening for CF. If an infant has it, beginning treatment right away can help delay or prevent complications. The screening involves taking asmall blood samplefrom the heel and sending it off to a laboratory for analysis.

People can undergo screening to check if they carry the CF genetic mutation. A healthcare professional takes a blood, saliva, or cheek cell sample for DNA testing. People may have this screeningbefore or duringpregnancy. Prenatal screening involves taking a sample of the amniotic fluid to check for the genetic mutation in the fetus.

The standard genetic test for CF checks for the23 most commongene mutations. There are over 1,700 mutations of the CFTR gene, however.

Prevention

There isno wayto prevent CF. If people are planning to have a child and are CF carriers, they may discuss this with a genetic counselor and consider their options.

Outlook

The Cystic Fibrosis Foundation reports that life expectancy and quality of life continue to improve for people with the condition.

Life expectancy varies from one person to the next and can depend on the severity of the disease.Research from 2021estimates that people with CF may reach their 40s before requiring a lung transplant. The median survival rate after lung transplantation is 8.5 years.

Receiving treatment as soon as possiblecan helpextend life, improve the quality of life, and prevent complications.

When to contact a doctor

Consult a doctor about any symptoms of CF.

People with CF should let a member of their healthcare team know about any significant changes in their symptoms.

Some peoplemay chooseto undergo screening for the genetic mutation. These tend to be:

• people with a family history of CF
• siblings, half-siblings, and first cousins of someone with CF
• people planning to become pregnant

Summary

CF is a genetic disorder linked to a mutation in the CFTR gene. This creates irregular proteins that cause mucus to become unusually thick and sticky.

CF primarily affects the lungs, though it can also affect the digestive system and other parts of the body.

Although there is no cure, treatments can help clear the mucus from the airways, aid digestion, and reduce the risk of complications. Continual advances in treatment improve life expectancy and the quality of life for people with CF. It is crucial to receive appropriate treatment as soon as possible.

How does cystic fibrosis cause respiratory infections?

Why does cystic fibrosis increase risk of infection?