Support Us: [email protected]
Normal Lungs: Your Lungs as a "Tree"
Your lungs can be likened to a "tree". When you breathe in, air is drawn through the nose and mouth into the windpipe (or trachea). This is the trunk of the tree. From the windpipe, air passes into two large bronchial tubes (bronchi), one supplying air to each lung. These bronchial tubes are the first "branches" of the tree. They divide into smaller and smaller branches, delivering air into tiny air sacs, called alveoli. The alveoli are the "leaves" of the tree. From these alveoli, oxygen is taken from the breathed-in air, and passed into the bloodstream. The oxygen is taken to all the organs of the body, such as the heart and brain.
Bronchiectasis: A Disease of the Bronchi ("Branches")
In bronchiectasis, the bronchial tubes become wider than usual (or dilated) and the wall of the tube becomes damaged and functions less effectively. The cilia on the wall of the affected tube are destroyed, so that mucus is no longer cleared away and collects in the tube. The collected mucus obstructs the flow of air through the affected bronchi, and eventually becomes contaminated with bacteria, causing bronchial infection. This infection causes inflammation in the bronchi. These damages the bronchial wall even further, and so we have a vicious circle of damage leading to infection leading to further damage and infection. The inflammation spreads to surrounding bronchi and lung tissue. Bronchiectasis can affect a small area of one lung (focal bronchiectasis) or affect widespread and different areas of the lungs (diffuse bronchiectasis), which is much more common.
Do we know what causes Bronchiectasis?
Despite extensive research, more than half of bronchiectasis cases have no definite etiology.
Post-infectious bronchiectasis and idiopathic bronchiectasis are currently the commonest reasons implicated.
When considering causes, it is most important to consider causes which can lead to disease modification. This includes certain immunodeficiencies, ciliary dysfunction, connective tissue diseases and COPD.
How do doctors diagnose Bronchiectasis?
A CT Thorax with high resolution images of the lung (HRCT Thorax) is the diagnostic test of choice for bronchiectasis.
In most cases, patient reported symptoms of increased phlegm and recurring respiratory tract infections along with crackles on thoracic auscultation lends to the initial suspicion of bronchiectasis.
How is Bronchiectasis treated?
Bronchiectasis is a chronic disease. Management is separate for acute exacerbations of the disease and management the stable patient.
Management of chronic bronchiectasis
Airway clearance techniques:
At diagnosis and at repeated intervals throughout the course of living with bronchiectasis, a patient should be educated on airway clearance techniques to help loosen up mucus in the lungs so it can be coughed up easily. This education is usually done by a physiotherapy or a specialist nurse. These techniques can also be referred to as active cycle of breathing techniques or chest physiotherapy. Frequently using airway oscillating devices (Acapella or flutter valve) or positive expiratory pressure devices will help as part of the exercises.
Exercise and pulmonary rehabilitation
Supervised exercise sessions or pulmonary rehabilitation can improve symptoms and exercise tolerance for patients. When possible patients should be linked with pulmonary rehabilitation as it provides a comprehensive education package beyond exercise by including group support, coping strategies for exertional symptoms, nutrition and a supervised environment to challenge deconditioning.
The management of chronic bronchiectasis starts after the attempt has been made at outruling possible etiologies which will allow the patient to benefit from disease centered treatments.
Characterizing the patient’s microbial profile
It is recommended that a patient should provide sputum samples for culture at every clinic or hospital visit. This surveillance microbiology will help guide empiric antibiotic therapy during exacerbations. In patients with frequent exacerbations, where sputum yield is inadequate, bronchoscopy is recommended to obtain a bronchoalveolar lavage.
Pharmacological therapies for bronchiectasis
Consider using prophylactic azithromycin in frequently exacerbating patients with bronchiectasis. The benefit is best seen in patients with clearly defined number of exacerbations (3 or more) as this long-term macrolide therapy doesn’t usually eliminate exacerbations but reduce the frequency. Via antibacterial and anti-inflammatory mechanisms, long-term macrolide has been validated in numerous trials. Patients might notice GI issues like diarrhea, nausea and vomiting and dyspepsia.
There is currently insufficient advice to support routine prescribing of hypertonic saline. Small trials have shown benefit when used in addition to airway clearance techniques in patients with viscous sputum and frequent exacerbations. In Ireland, only 3% and 7% hypertonic saline is currently allowed under the GMS prescribing scheme.
Pseudomonas aeruginosa infection in bronchiectasis
Considering the extensive evidence that Pseudomonas aeruginosa is correlated with poorer outcomes in bronchiectasis patients, experts suggest that an eradication attempt be made after first isolation of Pseudomonas in a patient. Oral ciprofloxacin for 2 weeks remains the first choice if oral antibiotics are used for P. aeruginosa eradication. If further treatment is indicated, 2 weeks of IV antipseudomonal antibiotics followed by either a prolonged course of oral ciprofloxacin or inhaled antibiotics.
In patients with chronic P. aeruginosa infection, long-term antibiotics should be considered for patients in >2 exacerbations per year. Experts acknowledge long-term macrolide therapy works well but resistance development particularly in NTM should preclude its use for this indication. Anti-pseudomonal inhaled antibiotics like inhaled gentamicin and nebulised colistin is preferred.
How do you assess severity and prognosis of bronchiectasis?
Certain patients with bronchiectasis tend to have a more severe form of this disease. This typically includes older patients, patients with poorer lung function, and patients who are colonized with Pseudomonas aeruginosa. Patients with multi-lobar involvement of bronchiectasis also can do poorly.
Physicians can use 2 scoring systems to help assess a patient; Bronchiectasis Severity Index or the FACED score.
Future developments in Bronchiectasis
There is increasing use of gene sequencing of respiratory specimens including both sputum samples and bronchoalveolar lavage specimens to facilitate improved detection of a patient’s microbial profile. This has been shown to be more sensitive and accurate than routine culture-based microbiological analysis.
New anti-inflammatory therapies have shown promising evidence in trials. One class are neutrophil elastase inhibitors which targets the neutrophilic inflammation associated with bronchiectasis. Another group being studied now are chemokine receptor 2 antagonists which has been shown to reduce airway inflammation through reduction in sputum neutrophil counts.