Bronchiectasis isn't one single disease. Rather, it is a condition that results from injury to the bronchi and bronchial tubes. These are the networks of airways in the upper chest that deliver air into the lungs after it passes down the throat through the windpipe.
Bronchiectasis refers to damage to the bronchi that prevents them from delivering air properly. The walls of the bronchi become permanently widened (dilated), scarred, or inflamed. Some bronchi may even collapse. It is characterized by production of large amounts of sputum (e.g., mucus, phlegm). The condition may spread or only affect a small area. Usually bronchiectasis causes widening in medium-sized bronchi, but smaller bronchi can be scarred or destroyed as well.
This condition can happen in different ways as a result of many different problems, all of which attack the bronchial wall by interfering with its defence system. Many medical conditions cause bronchiectasis. The most common cause is chronic or recurring infection. These infections may be caused by things such as immune system problems, birth defects affecting the structure or function of the airways, and blocked airways. A small number of cases result from breathing in toxic substances that hurt the bronchi.
The following is a list of some of the infections and conditions that can cause bronchiectasis.
- whooping cough
- viral infection
- bacterial infection
- fungal infection
- mycoplasma infection
Causes of blocked airways:
- lung tumour
- enlarged lymph glands
- inhaled foreign object
- cystic fibrosis
- ciliary dyskinesia, including Kartagener's syndrome
- alpha-1-antitrypsin deficiency
- immunoglobulin deficiency syndromes
- white blood cell problems
- autoimmune or hyperimmune disorders (rheumatoid arthritis, ulcerative colitis)
- toxic fumes, gases, or particles
- inhaling food or stomach acid
- HIV infection
- drug abuse, such as heroin use
Normally, the bronchial wall contains cells that protect the airways and lungs from harmful substances. Some of these cells produce mucus to trap foreign objects, while others remove the mucus from the airways.
In bronchiectasis, the bronchial wall becomes chronically inflamed or is destroyed. When this happens, the cells that clear the mucus can be hurt or killed. A mucus buildup then takes place that may further damage the bronchial wall and spread infection. The increased mucus may also allow bacteria to grow that can block the lung's large airways (the bronchus) and lead to low oxygen levels in the blood.
At the same time, the inflammation of the bronchi (plural of bronchus) may also spread to the small air sacs of the lungs (alveoli). If this happens, pneumonia can develop and result in scarring and a loss of lung tissue. In severe cases, scarring and a loss of blood vessels in the lungs may strain your heart.
Symptoms and Complications
People who suffer from bronchiectasis commonly have a chronic, productive cough. Bronchiectasis can develop at any time of life. The process usually starts in early childhood, although the symptoms may appear much later. Symptoms begin gradually, usually after bronchial infection, and get worse over the years. Most people develop a chronic cough and spit up material (sputum) from the lungs. Coughing up blood is not uncommon and may be the first or only symptom.
People may also experience coughing spells that take place early in the morning and at night. Frequent bouts of pneumonia, wheezing, or shortness of breath all may be signs of bronchiectasis. Bronchiectasis can be complicated by respiratory conditions like chronic bronchitis, asthma, and emphysema. Very severe cases may strain the heart and eventually lead to right heart failure.
Making the Diagnosis
A doctor may suspect bronchiectasis because of symptoms, or because a person has a condition related to it. X-rays can lead to a diagnosis and show the location and extent of the damage, but sometimes bronchiectasis is not revealed on regular X-rays. Bronchiectasis can usually be confirmed by high-resolution computed tomography (CT scan).
Once bronchiectasis is diagnosed, a doctor will check for diseases causing it. These tests may measure salt levels in the sweat to test for cystic fibrosis, or measure immunoglobulin levels in the blood. Samples from the nose or bronchi can show if the mucus-clearing cells are genetically defective. When bronchiectasis has affected only a small area, doctors may thread a tiny camera into the bronchi to see if a lung tumour or inhaled foreign object is the cause. This procedure is called fibre-optic bronchoscopy.
Other tests may be done to see if someone has allergic bronchopulmonary aspergillosis, a condition caused by a severe allergy to a kind of fungus. It causes a form of bronchiectasis that affects the large bronchi.
Treatment and Prevention
Cough suppressants won't help bronchiectasis and can make it worse. If the bronchi contain large amounts of mucus, they may have to be drained several times a day (postural drainage).
Infections can be treated with antibiotics. Antibiotics are sometimes prescribed for a week or two every month, or even continuously. Your doctor may also prescribe mucolytic medications that thin mucus, as well as anti-inflammatory medications such as corticosteroids. If the blood oxygen level is low because of blocked airways, oxygen therapy can help prevent the development of heart disease related to lung problems. If there is wheezing or shortness of breath, bronchodilator medications (medications that open up the airways) can help.
Surgery may be an option for people who have repeated infections or who cough up a lot of blood. Surgeons may remove the affected part of your lung, but it won't help if the bronchiectasis involves both lungs.
Effective prevention involves tackling the many causes behind bronchiectasis. Vaccinations for measles, whooping cough, flu, and pneumonia all help reduce its development, incidence, and spread. The early use of antibiotics during infections like tuberculosis and pneumonia may prevent bronchiectasis and reduce its severity. Using anti-inflammatory medications may prevent bronchial damage. Always avoid smoking or inhaling toxic fumes, gases, and harmful dusts.