What causes Lung failure in Cystic Fibrosis?

To understand how the cystic fibrosis lungs are impaired, we need to have a grasp of how the normal organ works.

The respiratory system includes bronchial tubes that branch and lead to the air sacs or alveoli at the terminal end. These air sacs are lined with cells that produce mucus secretions.

In normal conditions, the sacs produce watery, thin and runny mucus that also functions to coat the lung surfaces. When foreign particles like dust and germs enter the lungs, they become trapped in the mucus. Tiny hair-like structures on the surface of respiratory tubes called the cilia would sweep these foreign particles and mucus upward. As they reach the larger air passages up to the throat area, they can be swallowed or coughed out.

The Cystic Fibrosis Lungs

The problem with cystic fibrosis begins at the cellular level with a gene causing a malfunctionioning CFTR protein.

Defective Cystic Fibrosis Transmembrane Conductance Regulator

CFTR is a chloride transporter found in cells. This protein controls the flow of chloride ions out of these cells, which causes water to exit the cell. The water outside of the cell gives the mucus a normal, watery structure.

With cystic fibrosis, the CFTR does not allow chloride ions out of the cells. The water doesn’t leave the cells and the mucus becomes thick and sticky. Mucus is harder to evacuate and starts cloging the respiratory passageways, eventually leading to serious infections.

Pulmonary damage

The body further responds to the infections through the immune system by sending white blood cells to the lungs to try to eliminate the infection. The white blood cells release chemicals to destroy the bacteria and the surrounding cells, causing permanent damage to the respiratory system.

Vicious Circle

These white blood cells die after attacking the bacteria but add to the thickness of the mucus and impairment of the airways. The lungs of cystic fibrosis patients also develop a cycle of infection and inflammation.

Consequences for the patient

People suffering from cystic fibrosis typically have:

• Deep and productive coughing due to sticky mucus,
• Frequent pulmonary infections,
• Decreasing lung function due to scarring

Additional Respiratory Complications in Cystic Fibrosis

Several respiratory complications can later arise due to frequent scarring. These include:

• Pneumothorax or air build-up between the lungs and chest wall that causes the respiratory organ to collapse. This is more common in adults with CF.
• Blood in the sputum or coughing up small amounts of blood indicates a chest infection. Patients who cough up blood in very large amounts should immediately contact their doctor as this condition can be life-threatening.
• Cor pulmonale or enlargement of the right side of the heart. In the long run, this condition leads to heart failure and death.
• Pulmonary hypertension or increased lung pressure. Impaired oxygen supply from the lungs to the blood cells causes the arteries to constrict and the heart compensates this condition by pumping harder to increase blood flow in the vessels, which then increases pressure in the lungs.

As time goes by, the lungs become so damaged that it becomes life threatening for the patient. At that point, a transplant becomes necessary to safe the person’s life.

Treatments

Luckily, complications of the respiratory system in cystic fibrosis can be reduced by administering a number of medications. Prescriptions of these drugs depend on the patient’s symptoms and its severity. These medications include:

• Mucus-thinners such as Pulmozyme (Dnase) that loosen the mucus,
• Bronchodilators such as Albuterol, proventil and Ventolin that help clear the mucus and keep air passages open,
• Antibiotics such as TOBI (Tobramycin) which prevents and treats the infection, and
• Anti-inflammatory drugs like steroids and ibuprofen to help prevent lung inflammations.

Disclaimer: This website provides general information about cystic fibrosis and in no means should be taken as a medical or health advice. Please consult your doctor before acting on any of its information.