What is bronchiectasis?
Bronchiectasis is derived from the Greek words:
Bronckos – airway
Ectasis – widening
It is a chronic lung condition, defined as the abnormal, irreversible dilatation of the bronchi (Fig. 1), where the elastic and muscular tissue is destroyed by acute or chronic inflammation and infection. This damage impairs the natural drainage of bronchial secretions which can become chronically infected resulting in mild to moderate airway obstruction. Unless appropriately managed, the combination of infection and chronic inflammation, results in progressive lung damage.
Fig. 1 The Lungs
Depending on the aetiology, specific lobes or both lungs can be affected.
Although the site of damage, diagnosed by a high resolution computed tomography (HRCT) scan, is the larger airways, it is likely that the disease manifests itself in the smaller airways, which is not detected by an HRCT scan. Many patients may have experienced symptoms for many years before a diagnosis is confirmed.
Conversely, it is possible to have evidence of bronchiectasis on HRCT without clinical symptoms. This may be due to a process involving lung parenchyma with secondary fibrosis and retraction of the structures supporting the airway. This is called traction bronchiectasis and can be seen in patients with conditions such as interstitial lung disease.
Bronchiectasis can be classified into the following forms morphologically (Fig. 2) (all three forms may be present in the same patient):
Cylindrical bronchiectasis: bronchi are enlarged and cylindrical.
Varicose bronchiectasis: bronchi are irregular with areas of dilatation and constriction.
Saccular or cystic: dilated bronchi form clusters of cysts. This is the most severe form of bronchiectasis and is often found in patients with cystic fibrosis
Fig. 2 Types of bronchiectasis
Identification of four clinical phenotypes in bronchiectasis may assist with focusing treatments in future intervention studies (Aliberti et al 2016):
Presence of Pseudomonas
Other chronic infection
Daily sputum production