Definition - Bronchiectasis is the permanent dilatation of bronchi due to the destruction of the elastic and muscular components of the bronchial wall
- It is often caused as a consequence of recurrent and/or severe infections secondary to an underlying disorder
- The majority of patients will present with a chronic cough and sputum production
Risk Factors - Strong
- cystic fibrosis
- host immunodeficiency
- previous infections
- congenital disorders of the bronchial airways
- primary ciliary dyskinesia
- Weak
- alpha-1 antitrypsin deficiency
- connective tissue disease
- inflammatory bowel disease
- aspiration or inhalation injury
- focal bronchial obstruction
- rheumatoid arthritis
Differential diagnosis - COPD
- Rhonchi in combination with diminished breath sounds, characterising COPD, are not found in bronchiectasis.
- In bronchiectasis, rhonchi may be auscultated, but with additional inspiratory squeaks and crackles.
- Chest CT may be normal or show emphysema in COPD, as opposed to the characteristic abnormal results found in bronchiectasis
- Thickened, dilated airways with or without air fluid levels
- Varicose constrictions along airways
- Ballooned cysts at the end of a bronchus
- Tree-in-bud pattern
- Patients with COPD may also develop bronchiectasis.
- Asthma
- Inspiratory squeaks and crackles, often present in bronchiectasis, are not present in asthma.
- Airflow obstruction is often reversible in asthma.
- Chest CT may be normal or show mosaicism in asthma, as opposed to the characteristic abnormal results found in bronchiectasis
- Pneumonia
- Patients with pneumonia describe symptoms of short duration (7 to 10 days), as opposed to years in bronchiectasis.
- Auscultation findings (rhonchi, wheezing, crackles) may be similar in bronchiectasis and pneumonia, especially multi-lobar pneumonia.
- CXR and chest CT results in pneumonia are quite variable and often depend on aetiology.
- In bronchiectasis, there is characteristic dilatation of bronchi without airway thickening.
- Chronic sinusitis
- The inspiratory squeaks and crackles found in bronchiectasis are uncommon in chronic sinusitis.
- CXR and chest CT are normal in chronic sinusitis
- Sinus CT shows opacification of the involved facial sinus in chronic sinusitis.
Epidemiology - The prevalence worldwide is unknown due to the lack of standardised medical care and poor healthcare access in underdeveloped countries
- In the US, an estimated 110,000 individuals are affected
- The disease appears more common in the older population and in women. [5]
- In the UK, incidence is estimated at 1.06 to 1.3 per 100,000 population. [6]
- In general, it is estimated that the incidence has decreased over the past several decades due to implementation of vaccination programmes and the development of more potent antibiotics.
- Infection is the most common cause of bronchiectasis in underdeveloped countries. [8]
- Factors that affect mortality in patients with moderate to severe bronchiectasis include:
- advanced age
- St George's Respiratory Questionnaire activity score
- Pseudomonas aeruginosa infection
- total lung capacity (TLC)
- residual volume divided by TLC
Aetiology - Post-infectious
- Prior childhood respiratory infections due to viruses
- measles, influenza, pertussis
- Prior infections with Mycobacteria tuberculosis or severe bacterial pneumonia
- Exaggerated response to inhaled Aspergillus fumigatus
- Swyer-James or Macleod's syndrome
- Chronic manifestation of bronchiolitis or pneumonitis in childhood, characterised by unilateral pulmonary hypoplasia and radiographic hyperlucency
- Immunodeficiency
- Host immunodeficiency (primarily immunoglobulin deficiency)
- Selective immunoglobulin deficiency
- HIV infection.
- Genetic
- Cystic fibrosis
- Ciliary dyskinesia or immotile cilia syndrome
- Kartagener's syndrome
- Autosomal-recessive condition characterised by the triad of bronchiectasis, situs inversus, and chronic sinusitis
- Young's syndrome
- A condition, believed to be genetic, characterised by obstructive azoospermia with normal sperm production plus chronic or recurrent sinus and lung infections
- Alpha-1-antitrypsin deficiency
- Mounier-Kuhn syndrome
- Also known as tracheobronchomegaly, characterised by abnormal dilatation of the trachea and main bronchi
- Williams-Campbell syndrome
- Also known as tracheomalacia, characterised by absence or weakness of bronchial cartilage, leading to bronchial collapse
- Yellow nail syndrome
- Pulmonary sequestration
- Aspiration or inhalation injury
- Connective tissue disorders
- Rheumatoid arthritis
- Sjogren's syndrome
- Ehlers-Danlos syndrome
- Marfan's syndrome
- Inflammatory bowel diseases
- Ulcerative colitis
- Crohn's disease.
- Focal bronchial obstruction
- Foreign body
- Broncholith
- Stenosis
- Tumour
- Adenopathy with extrinsic compression
- Idiopathic
- Other
- Persistent colonisation with Mycobacterium avium-intracellulare
- Diffuse panbronchiolitis
- Bronchopulmonary sequestration
Clinical features - Presence of risk factors (common)
- Cough (common)
- Occurs in 98% of patients and is the most common symptom of bronchiectasis.
- An acute exacerbation often presents as worsening of cough.
- May be associated with large amounts of foul-smelling sputum, and less commonly haemoptysis.
- Cough may be worsened by lying on one side
- Sputum production (common)
- Daily sputum production is present in two-thirds of patients.
- Bloody sputum is present in about 50% of patients and is usually mild (i.e., sputum with flecks of blood).
- Sputum production will often increase during acute respiratory infections.
- An acute exacerbation often presents as a change in sputum colour and an increase in sputum volume.
- Crackles, high-pitched inspiratory squeaks and rhonchi (common)
- Many patients will have crackles on pulmonary auscultation.
- Crackles may be associated with high-pitched inspiratory squeaks and rhonchi.
- Dyspnoea (common)
- Present in majority of patients, especially with exertion.
- Often correlates with severity of bronchiectasis on chest CT.
- Fever (common)
- More than half of patients with bronchiectasis will have recurrent episodes of fever.
- An acute exacerbation often presents with fever.
- Pallor (common)
- Fatigue (common)
- A non-specific symptom.
- An acute exacerbation often presents with fatigue.
- Haemoptysis (common)
- Present in about 50% of patients and is usually mild (i.e., sputum with flecks of blood).
- Thought to originate from the bronchial arteries or bronchial-pulmonary anastomoses.
- May become massive (>250 mL/day), which warrants hospital admission and immediate referral to a pulmonologist and/or a thoracic surgeon.
- Rhinosinusitis (common)
- Bronchiectasis due to a primary mucociliary clearance defect, such as primary ciliary dyskinesia or cystic fibrosis, will probably be accompanied by symptoms of rhinosinusitis.
- May indicate the presence of Kartagener's syndrome, a rare autosomal recessive disorder of impaired ciliary activity that includes situs inversus, bronchiectasis, and chronic sinusitis.
- Weight loss (common)
- Wheezing (uncommon)
- Present in one quarter of patients, but more common in bronchiectasis patients who are also smokers.
- Pleuritic chest pain (uncommon)
- May be present, especially during periods of fever.
- Clubbing (uncommon)
- Clubbing of the digits is rare
Pathophysiology - The dilatation and thickening of the bronchi seen in bronchiectasis are due to chronic inflammation elicited by the host response to micro-organisms colonising the airways.
- This persistent airway inflammation leads to the subsequent development of bronchial wall oedema and increased mucus production.
- Several inflammatory cells including neutrophils, T lymphocytes, and other immune effector cells are recruited to the airways
- Subsequently release inflammatory cytokines, proteases, and reactive oxygen mediators implicated in the progressive destruction of the airways
- This initial insult to the airways by the primary infection leads to increased inflammation
- Results in bronchial damage
- Serves as a nidus for subsequent colonisation of the airways
- As a result, a vicious cycle ensues
- Predisposes to persistent bacterial colonisation and to a subsequent chronic inflammatory reaction that eventually leads to progressive airway damage and recurrent infections.
- The factors that predispose individuals with an initial infection to go on to develop bronchiectasis remain unclear.
Investigations- CXR
- May be normal or show obscured hemidiaphragm, thin-walled ring shadows with or without fluid levels, tram lines, tubular or ovoid opacities
- High-resolution chest CT
- Thickened, dilated airways with or without air fluid levels; varicose constrictions along airways; cysts and/or tree-in-bud pattern
- FBC
- High WBC may show high eosinophil count in bronchopulmonary aspergillosis; neutrophilia suggests superimposed infection or exacerbation
- Sputum culture and sensitivity
- Gram-positive bacteria; gram-negative bacteria; non-tuberculous mycobacteria; fungi
- Serum alpha-1 antitrypsin phenotype and level
- Presence of S or Z alleles and MM phenotype indicates alpha-1 antitrypsin deficiency
- Serum immunoglobulins
- Decreased IgG, IgM, and/or IgA in immunodeficiency states
- Sweat chloride test
- >60 mEq/L in cystic fibrosis
- Rheumatoid factor
- Positive in rheumatoid arthritis
- Aspergillus fumigatus skin prick test
- Immediate cutaneous reactivity to antigen in bronchopulmonary aspergillosis
- Serum HIV antibody
- Positive in HIV infection
- Exhaled nitric oxide
- Low exhaled nasal nitric oxide level in primary ciliary dyskinesia
- Pulmonary function tests
- Reduced FEV1 or FEV1/FVC ratio (<70%)
- C-reactive protein
- An elevated C-reactive protein suggests active inflammation and is associated with a faster decline in lung function
- Bronchial biopsy and electron microscopy of cilia
- Abnormal ciliary morphology in primary ciliary dyskinesia
- Cystic fibrosis transmembrane regular protein gene mutation testing (CFTR)
- Positive in cystic fibrosis
- Swallow study
- Aspiration in patients with chronic aspiration
- Sputum pH monitoring
- Low pH in patients with chronic aspiration
- 6-minute walk test
- Reduced in those with significantly reduced lung function
Managementa) conservative- exercise and improved nutrition
- airway clearance therapy
b) medical - bronchodilators
- hyperosmolar agents
- long-term oral macrolides
- inhaled corticosteroids
-
oral antibiotics
c) surgical- Complete resection of bronchiectatic areas of the lung may be appropriate in some patients with refractory disease
Prognosis- Bronchiectasis is an irreversible condition.
- The typical disease course consists of periods of symptom control interrupted by periods of exacerbations.
- Bronchiectasis frequently co-exists with other respiratory disease, making it difficult to determine prognosis for bronchiectasis alone
- Factors associated with a faster decline in lung function include:
- More frequent severe exacerbations
- Increased systemic inflammation (determined by CRP)
- Quality of life
- According to the St. George Respiratory Questionnaire, these factors have the greatest impact on the quality of life in patients with bronchiectasis:
- Dyspnoea
- Reduced FEV1
- Daily sputum production
- Pseudomonas species in sputum
- Indicates more extensive lung disease and more severe impairment of pulmonary function than in patients without Pseudomonas species colonisation.
- Some studies have shown that Pseudomonas species colonisation is an independent factor associated with a faster decline in lung function.
- Evidence is conflicting. [52]
- Hypoxaemia, hypercapnia, dyspnoea, and radiographic extent of disease have been shown to correlate with mortality.
- Conversely, a higher BMI, regularly scheduled doctor visits, and vaccinations improve survival.
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