Bronchiectasis is the permanent dilatation of bronchi and bronchioles caused by destruction of the muscle and supporting elastic tissue, resulting from (or associated with) chronic necrotizing infections.
Bronchiectasis is uncommon and its global epidemiologyis not well reported. In Finland, the overall incidence is 3.98 per 100 000 per year, with a bimodal distribution: 0.49 per 100 000 per year in the young (0-14 years) and 10.4 per 100 000 per year in the elderly (over the age of 65).
Bronchiectasis itself is not a primary disorder but occurs as a complication of other diseases . The pathogenesis is due to two related processes, distal airways obstruction and persistent chronic infection. Chronic infection (as a primary event or distal to an obstructed airway) damages the bronchial walls, leading to weakness and dilatation (usually visible on chest X-ray and CT scan). Conversely, chronic infection can cause obstructive secretions, inflammation, fibrosis and scarring of the airways, leading to obstruction. Eventually fibrosis and scarring develops. Bronchial wall thickening as a result is thought to be an important determinant in the development and progression of an obstructive lung defect on pulmonary function testing.
Scope of disease
Depending on the aetiology, bronchiectasis may be localized to a lobe (foreign body obstruction) or diffuse and involving both lungs (primary ciliary dyskinesia). Recurrent lower respiratory tract infection is a common complication, a third of patients have sinusitis, and amyloidosis may complicate chronic cases. Male patients with cilial disorders may have associated infertility.
Causes of bronchiectasis includes bronchial obstruction such as foreign bodies, mucus impaction, tumor, bacterial or viral pneumonia, tuberculosis, whooping cough , allergic bronchopulmonary aspergillosis, cystic fibrosis, primary ciliary dyskinesia, primary immune deficiency , chlorine or heroin overdose, rheumatoid arthritis, SLE, inflammatory bowel disease, Young syndrome ( secondary cilia dyskinesia ) and acquired immune deficiency .
Cough and chronic (daily) purulent sputum production are the two main symptoms of bronchiectasis. The absence of a smoking history makes the diagnosis much more likely, and is an important differentiating feature from COPD (the two may coexist in smokers). Dyspnoea, wheezing, haemoptysis (especially during infective exacerbations), malaise and fatigue can also result. It is important also to screen for any of the causes listed above which would further support the diagnosis.
On examination the patient may be cachetic with clubbing and halitosis. On auscultation coarse crepitation and wheezing may be audible (either localized or widespread depending on the extent of the disease).
Radiographic imaging and anatomical visualization of dilated bronchi confirms the diagnosis of bronchiectasis. The chest film may be abnormal with linear atelectasis or tramlines (visible thickened bronchial walls), ring-like shadows (bronchial walls end on) or focal areas of consolidation.
High-resolution CT is currently the imaging modality of choice, clarifying the plain film findings and providing a detailed map of disease. Pathological dilatation of the bronchial lumen is defined as a width of more than 1.5 times the size of an adjacent blood vessel. Cystic dilatations, thickened bronchial walls, mucus plugs and lymphadenopathy may also be visible.
Lung function tests
Spirometry often reveals an obstructive defect (FEV1/FVC ratio <70%). Assessment for bronchodilator reversibility, present in 20-40%, is an important adjunct that assists medical management.
Sputum microscopy and culture
This is performed to determine the type and antibiotic sensitivities of colonizing pathogens and provides useful information during subsequent admissions for infective exacerbations.
Specific investigations for an underlying cause
Guided by the history and clinical features, specific investigations may be required to screen for foreign body (bronchoscopy), allergic aspergillosis (skin allergen testing, IgE and RAST to aspergillus), primary ciliary dyskinesia (nasal mucociliary clearance test) and congenital immunodeficiencies (immunoglobulin levels).
The aims are to interrupt the cycle of infection and inflammation. Conventional therapy usually involves physiotherapy and intermittent antibiotic therapy for exacerbations.
Physiotherapy and mucus clearance.
Exercise is encouraged, and patients are taught postural drainage and mucus clearance techniques such as active cycles of breathing (ACBT).
Maintaining adequate systemic hydration is important for patients with thick and viscous sputum; in addition, nebulized saline may be required.
Bronchodilator therapy improves pulmonary function in patients with reversible airflow obstruction.
Antibiotic prescription is usually reserved for acute infective exacerbation, although nebulized aminoglycosides may be useful for a subgroup of patients with advanced disease. The evidence for long-term antibiotic therapy is limited; although there is a significant response, there are no differences in the frequency of subsequent exacerbations or in lung function.
Management of exacerbations
Exacerbation of bronchiectasis is suggested by a combinaion of increasing cough or sputum production, worsening dyspnoea, reducing exercise tolerance, pyrexia, increased wheezing, reduced pulmonary function or new X-ray changes. Common pathogens responsible for infective exacerbation are H. influenzae (amoxicillin), M. catarrhalis and P. aeruginosa (ciprofloxacin). Antibiotic prescription in this setting should be pathogen specific and sensitivities may be known from previous sputum cultures.
The role of surgery in bronchiectasis is limited. The main indications are removal of the offending stimulus (foreign body), management of complications (haemoptysis) and, in selected patients, excision of the bronchiectatic segments of lung.
Lung resection for bronchiectasis may be an option for patients with localized disease that is amenable to resection. The indications are progressive disease despite medical therapy, massive haemoptysis and the development of a lung abscess. Details of lung resection are provided on page .
Bronchiectasis tends to be a relatively stable disease. The decline in pulmonary function is similar to the general population in non-smoking patients, and more accelerated in smokers. Spontaneous improvements compared to the time of diagnosis occur in a third. Survival is related to the severity of pulmonary function impairment and the presence of right heart failure.
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