The Facts

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 (mucus, phlegm, etc.). 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.

Causes

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 defense 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.

• Respiratory infections:
  • whooping cough
  • measles
  • flu
  • tuberculosis
  • viral infection
  • bacterial infection
  • fungal infection
  • mycoplasma infection
• Causes of blocked airways:
  • lung tumor
  • enlarged lymph glands
  • inhaled foreign object
  • mucus
• Genetic conditions:
  • cystic fibrosis
  • ciliary dyskinesia (including Kartagener's syndrome)
  • alpha 1-antitrypin deficiency
• Immune problems:
  • immunoglobulin deficiency syndromes
  • white blood cell problems
  • autoimmune/hyperimmune disorders (rheumatoid arthritis, ulcerative colitis)
• Inhalation injuries:
  • toxic fumes, gases, or particles
  • inhaling food or stomach acid
• Other conditions:
  • HIV infection
  • drug abuse, such as heroin abuse

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; 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 build-up 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.