What Is Bronchiectasis (Bronchiectasia)?
Bronchiectasis, also known as bronchiectasia, is a lung condition that causes persistent cough and excess phlegm (sputum); it is defined by localized, irreversible dilation (widening) of part of the bronchial tree - the airways widen, become flabby and scarred. Bronchiectasis, along with emphysema, bronchitis and cystic fibrosis is classified as an obstructive lung disease.
Air enters and leaves the lungs through a series of branching airways called bronchial tubes (airways). In a healthy individual, the bronchial tubes narrow smoothly towards the edges of each lung. In patients with bronchiectasis, however, the airways of the lungs are damaged - irreversibly - instead of narrowing they widen.
The airways of the lungs are covered in mucus and cilia. Mucus is a slimy liquid and acts as a protective blanked against undesirable particles that get into the lungs. Cilia are hair-like structures which sweep the particles and excess mucus upwards, out of the lung - they sweep in unison. Usually what comes out is unnoticeable; if excess mucus is pushed up we cough.
In the bronchial tubes of a person with bronchiectasis, the cilia are destroyed. As there is no (or very little) sweeping upwards of particles and mucus, it accumulates, as do bacteria. The sputum (phlegm) can become extremely sticky and difficult to shift, even with coughing.
The accumulated sputum is an ideal environment for bacteria to multiply and infect the lungs, further damaging the bronchial tubes. A vicious cycle occurs, of sputum buildup, more bacteria, more infection, more damage, which leads to further sputum build up, etc.
- The airways lose their ability to clear out mucus.
- Mucus consequently builds up, creating an environment in which bacteria can multiply.
- This leads to recurrent (serious), serious lung infections.
- Each infection further damages the airways.
- Eventually the airways lose their ability to move air in and out of the lungs.
- Consequently, the body's ability to get enough oxygen to vital organs is undermined.
- Patients are at higher risk of developing serious health problems, such as respiratory failure, heart failure and atelectasis (collapse of part or all of a lung).
Bronchiectasis used to start nearly always during childhood. These days it usually develops much later in life, around middle age, or even after that, mainly because hygiene standards have improved, antibiotics, as well as childhood immunization programs. In industrialized countries bronchiectasis is generally caused by an underlying medical condition that damages the airway walls or prevents them from shifting mucus, such as cystic fibrosis or primary ciliary dyskinesia.
If bronchiectasis affects only one part of the lung, it is usually caused by a blockage, and not an underlying condition.
Bronchiectasis is incurable. Early diagnosis and treatment can stop the progression of the disease. It can be either an acquired or congenital (born with it) condition.
Rene Laennec (1781-1826), a French physician who invented the stethoscope, used his invention to first discover bronchiectasis. It was later researched by Sir William Osler (1849-1919), a Canadian physician. Osler is thought to have died of complications from undiagnosed bronchiectasis.
According to Medilexicon's medical dictionary:
- Bronchiectasis is "chronic dilation of bronchi or bronchioles as a sequel of inflammatory disease or obstruction often associated with heavy sputum production."
Congenital bronchiectasis is "a rare form of bronchiectasis due to developmental arrest in the tracheobronchial tree; may be unilateral or bilateral."