The bronchi are the air passages that lead from the trachea (windpipe) to each lung – right and left. It divides into smaller tubes known as bronchioles which lead straight to the air sacs of the lungs. The bronchi and bronchioles are an important site of various common respiratory diseases. When it is infected and inflamed, it is known as bronchitis and bronchiolitis. Reversible narrowing of the bronchi and bronchioles that is often related to allergies is known as asthma. There are other lesser known diseases of the bronchi with bronchiectasis being one of the more significant of these conditions.
What is bronchiectasis?
Bronchiectasis is an abnormal widening of the airways – bronchi and bronchioles – that is permanent. The irreversible dilatation is often a consequence of repeated and severe respiratory tract infections in people without congenital or hereditary conditions. This damages and even destroys the muscle and elastic tissue of the bronchial walls. In addition, the tiny hair-like projections lining the airways known as cilia are destroyed.
The destruction makes the bronchial walls flabby and this can lead to outpouchings within the airways. At the same time large amounts of mucus can collect within the airways and outpouchings and due to the lack of cilia, it cannot be pushed out of the respiratory passages. This creates the ideal environment for ongoing infections, particularly bacterial, and compromises treatment of otherwise minor respiratory tract infections. Over time the repeated infections and inflammation causes death of the tissue and scarring.
Causes of Bronchiectasis
In children, bronchiectasis is often associated with congenital conditions like cystic fibrosis which can continue throughout adulthood. Other congenital and hereditary conditions in both children and adults includes :
- Ciliary dysfunction syndromes – primary ciliary dyskinesia or Kartagener’s syndrome
- Primary hypogammaglobulinaemia
- Immunodeficiency states
Among the acquired causes in children and adults, the following should be considered :
- Pneumonia may arise as a complication of whooping cough or measles in children and recurrent cases in adults may be associated with immune deficiency states and HIV infections should also be considered.
- Obstruction of the respiratory tract may be due to a foreign body, tumors or impacted mucus.
- Autoimmune causes associated with inflammatory bowel disease (IBD), systemic lupus erythematosus (SLE) and rheumatoid arthritis or associated with organ transplant (post-transplantations).
Difference between Bronchitis and Bronchiectasis
Bronchitis and bronchiectasis are two different disease affecting the bronchi and bronchioles. It is sometimes mistaken for each other due to the similarity of the names and symptoms. Repeated bronchitis may lead to bronchiectasis and some patients may have pre-existing chronic bronchitis and develop bronchiectasis.
As mentioned above, bronchitis is an inflammation of the walls of the bronchi and bronchioles which causes narrowing. Bronchiectasis on the other hand is a widening of the bronchi and bronchioles although excessive mucus production does narrow the bronchial tree.
Acute bronchitis is completely reversible with time and the appropriate treatment. Even chronic bronchitis is not necessarily permanent if patients take the appropriate measures like quitting cigarette smoking at an early stage. Bronchiectasis, however, is permanent and therefore irreversible.
Bronchitis is associated with severe inflammation while bronchiectasis is a result of structural destruction and superimposed inflammation. Due to the inflammation in both conditions, the signs symptoms are often similar. However, bronchiectasis can lead to coughing up of blood (hemoptysis) that can even be life threatening.
Signs and Symptoms of Bronchiectasis
Patients with bronchiectasis present with :
- Chronic cough – productive (excessive mucus)
- Expectoration of foul smelling mucus
- Coughing up blood (hemoptys) – acute hemptysis can be life threatening
- Recurrent fever
- Chest pain
Symptoms tend to develop gradually and may be of low intensity in the early stages until acute exacerbations. Sometimes it does not present with these typical symptoms and patients just complain of a persistent productive cough. This can be misleading as some patients who are cigarette smokers may be incorrectly diagnosed with bronchitis until more severe and typical symptoms appear.
Bronchiectasis may also present with symptoms like difficulty breathing and wheezing which may sometime be mistaken with asthma. In severe cases, the following symptoms may be seen :
- Clubbing of the fingers
- Pallor – paleness of the skin
- Cyanosis – bluish skin discoloration
- Weight loss