Bronchiectasis is a disorder characterised by permanent dilatation of the bronchi due to chronic infection or inflammation which leads to destruction of the elastic and muscular portions of the bronchial wall.
Pathophysiology
Chronic inflammation occurs due to a response to a micro-organism which colonises the airways. This chronic inflammation causes dilatation and bronchial thickening and subsequent oedema and increased mucus production.
This inflammatory response is mediated by neutrophils, T-cells, cytokines, proteases and ROS.
It causes a cyclical response wherein the insult to the airways leads to more inflammation and thus the damage ensues, coupled with impaired mucociliary clearance that comes with inflamed bronchi it allows the airways to be colonised by more bacteria which again continue the inflammatory response.
The causes of bronchiectasis are numerous, but some notable causes include:
- Post-infectious - TB, pertussis, pneumonia, COVID-19. Measles in children is especially notable.
- COPD and asthma
- Connective tissue disorders
- Immunodeficiency - seen in HIV or immunoglobulin deficiency.
- Genetic causes
- Cystic fibrosis
- Ciliary dyskinesia syndromes such as Kartagener syndrome
- Alpha-1- antitrypsin deficiency
- IBD
- Bronchial obstruction - foreign body, broncholith, tumour
- Yellow nail syndrome - a rare disease characterised by slow-growing, hard, yellow nails; lymphoedema and bronchiectasis.
- Ehlers-Danlos syndrome, Marfan syndrome
- Idiopathic
- Allergic bronchopulmonary aspergillosis (ABPA) - a disorder characterised by an exaggerated response to aspergillus fumigatus.
A rare, autosomal recessive genetic disorder that has a triad of:
- Situs invertus
- Chronic sinusitis
- Bronchiectasis
Subfertility is also a common finding.
⚠️ Risk factors
- Cystic fibrosis
- Immunodeficiency
- Previous infection - as mentioned above.
- Congenital bronchi disorders
- Primary ciliary dyskinesia - as mentioned above
😷 Presentation
- Persistent productive cough - a productive cough persisting more than 8 weeks is suspiciously indicative of bronchiectasis. The cough may be worse when lying flat or on one side.
- Expectoration of large volumes of purulent sputum
- Dyspnoea
- Fever - episodes of fever may come and go. Acute exacerbations of bronchiectasis often present with fever though.
- Haemoptysis - about half of the patients with bronchiectasis have haemoptysis. A cause for concern, warranting hospital admission and urgent referral is massive haemoptysis (>250ml/day).
- Fatigue
- Coarse crackles - especially in the lower lung zones.
- Wheeze - more prevalent with concomitant asthma.
- High-pitched inspiratory squeaks
- Large airway rhonci (low-pitched snore-like sounds)
🔢 Classification
The Reid classification of bronchiectasis is used to describe the morphological manifestations of bronchiectasis. There are 3 types:
- Cylindrical bronchiectasis - enlarged and cylindrical bronchi. The normal tapering of the bronchi are not present.
- Varicose bronchiectasis - irregular dilatation and constriction of the bronchi, resembling varicose veins.
- Saccular/cystic bronchiectasis - the most severe form. Found mainly in patients with CF. The bronchi are dilated and form a cluster of air-filled or fluid-filled cysts.
🔍 Investigations
There are a number of tests that we need to do:
- Sputum culture - to try and identify and colonising pathogens.
- CXR - used to exclude other pathologies, but can be diagnostic in severe cases. Some features will include dilated and thickened airways and
- Spirometry - to assess severity of obstruction and identify and co-existent COPD.
- Oxygen saturations
- FBC - WCC may show eosinophilia (with aspergillosis) or neutrophilia if there is an infectious cause/exacerbation.
- 🏆 High-resolution CT chest - this is the gold-standard for diagnosis of bronchiectasis. They will show thickened and dilated airways.
- Some other investigations may be done to try and identify the cause of the disease:
- Cystic fibrosis testing - such as gene testing or sweat chloride testing.
- Antibody deficiency screening
- Serum total immunoglobulin - IgE is raised with aspergillus.
- Primary ciliary dyskinesia testing
- Bronchoscopy may allow clinicians to locate obstructed areas and take samples for cultures.
🧰 Management
Let’s take a look at the initial management plan, then let’s discuss how to manage infective exacerbations of bronchiectasis:
- Exercise therapy - exercise is a form of airway clearance and has shown to improve the quality of life and reduced exacerbation frequency. For patients with cystic fibrosis, it is not as effective unfortunately.
- Physiotherapy - physiotherapists can help with postural drainage techniques. It is recommended to use these techniques 15-30 minutes twice a day.
- Smoking cessation
- Antibiotics can be given in cases of exacerbation. Or if they have severe bronchiectasis, long-term rotating antibiotics may be given, adhering to local protocols (see below).
- Bronchodilator - a nebulised bronchodilator prior to mucoactive agent is recommended especially in patients with concomitant asthma/COPD.
- Salbutamol - up to 4 times daily when required (1-2 puffs at a time).
- Corticosteroid - may be given in cases of ABPA.
- Prednisolone
- Mucolytic agent - these help reduce the viscosity of the sputum to promote expectoration of the mucus.
- Nebulised hypertonic saline
- Carbocysteine
- Immunisations - these should be given if missing and annual immunisations should also be given where needed.
- Hospital admission - if the patient has significant comorbidities or are in need of IV antibiotics (showing signs of cyanosis, confusion, rapid respiration, peripheral oedema, pyrexic).
- Sputum cultures need to taken to guide antibiotic therapy.
- Antibiotics
- Pseudomonas aeruginosa - follow local guidelines (usually ciprofloxacin).
- Other bacterial agent → amoxicillin or co-amoxiclav given 3x daily for 7-14 days
- Clarithromycin may be given if there is a penicillin allergy.
If a patient has 3 or more exacerbations per year they may be offered antibiotic prophylaxis: azithromycin or erythromycin are the first-line options.
In these patients, it is also important to review their postural drainage technique and also their mucolytic agent.
Here is a list of the most common causative agents in infective exacerbations:
- Haemophilus influenzae - the most common.
- Pseudomonas aeruginosa - the most severe.
- Klebsiella spp.
- Streptococcus pneumoniae
Surgical resection may be used for localised disease. However, very severe cases may even indicate lung transplantation.