What is bronchiectasis, its symptoms, treatment, and management in patients, particularly older adults with a history of respiratory infections or conditions like cystic fibrosis?

Bronchiectasis Overview

Bronchiectasis is a chronic respiratory disease characterized by permanent, irreversible bronchial dilatation on CT scan combined with a clinical syndrome of chronic productive cough, sputum production, and recurrent respiratory infections. 1

Definition and Pathophysiology

Bronchiectasis involves destruction of the elastic and muscular components of bronchial walls, leading to abnormal and permanent airway dilation. 2 The disease perpetuates through a vicious cycle of chronic bacterial infection, inflammation, impaired mucociliary clearance, and progressive structural lung damage. 1, 3

Key pathophysiologic features include:

• Neutrophilic inflammation with release of elastase and collagenase that destroy bronchial walls 2
• Mucus stasis leading to bacterial colonization and chronic infection 2
• Progressive airway architectural changes fostering polymicrobial communities 4

Clinical Presentation

Primary symptoms include:

• Chronic productive cough with viscid, often foul-smelling sputum 5, 6
• Recurrent respiratory infections and exacerbations 1, 6
• Dyspnea and fatigue 1
• Hemoptysis in some cases 2
• Digital clubbing may be present 2

The condition predominantly affects older adults, with prevalence increasing dramatically with age (7 per 100,000 in ages 18-34 versus 812 per 100,000 in those ≥75 years), and is more common in women (180 per 100,000) than men (95 per 100,000). 6

Etiology

Common causes include:

• Post-infectious (following pneumonia, tuberculosis, whooping cough, severe measles) 5, 6, 7
• Nontuberculous mycobacterial infection 6
• Immunodeficiencies (common variable immunodeficiency present in 2-8% of cases) 8
• Genetic conditions (α1-antitrypsin deficiency, primary ciliary dyskinesia) 2, 6
• Autoimmune diseases (rheumatoid arthritis, inflammatory bowel disease) 6
• Allergic bronchopulmonary aspergillosis 8, 6
• Idiopathic (up to 38% of cases) 6

Associated comorbidities include gastroesophageal reflux disease (47%), asthma (29%), and COPD (20%). 6

Diagnostic Approach

High-resolution CT (HRCT) is essential for diagnosis, showing abnormal bronchial dilatation, airway wall thickening, and mucus plugging. 1, 2, 6

Initial diagnostic workup should include:

• Differential blood count to identify immune deficiency or hematological malignancy 8
• Serum immunoglobulins (IgG, IgA, IgE, IgM) to detect common variable immunodeficiency 8, 6
• Testing for allergic bronchopulmonary aspergillosis 8, 6
• Sputum cultures for bacteria, mycobacteria, and fungi 8, 6
• Pre- and post-bronchodilator spirometry 6
• Pulse oximetry to screen for respiratory failure 3

Treatment and Management

Non-Pharmacological Interventions

All patients with chronic productive cough must be taught airway clearance techniques by a trained respiratory physiotherapist, performing 10-30 minute sessions once or twice daily, regardless of disease severity. 3 This is the cornerstone of therapy to prevent mucus stasis and progressive lung damage. 3

Pulmonary rehabilitation is strongly recommended for patients with impaired exercise capacity, consisting of 6-8 weeks of supervised exercise training to improve exercise capacity, reduce cough symptoms, and enhance quality of life. 3, 6

Consider nebulized sterile water or normal saline to facilitate airway clearance and address mucus plugging. 3 Acetylcysteine is FDA-approved as adjuvant therapy for abnormal, viscid mucous secretions in bronchiectasis. 9

Pharmacological Management

Obtain sputum culture to identify pathogens, particularly Haemophilus influenzae and Pseudomonas aeruginosa. 3 P. aeruginosa infection is associated with three-fold increased mortality risk, seven-fold increased hospitalization risk, and one additional exacerbation per year. 3

For acute exacerbations (presenting with increased cough, sputum, and worsened fatigue), treat with 14 days of antibiotics based on previous sputum culture results:

• Amoxicillin for Streptococcus pneumoniae and Haemophilus influenzae 3
• Ciprofloxacin for Pseudomonas aeruginosa 3

For patients with ≥3 exacerbations per year, consider long-term antibiotic therapy with azithromycin (250 mg daily or 500 mg three times weekly) or inhaled antibiotics (colistin, gentamicin). 1, 3, 6 Treatment should continue for a minimum of 6-12 months to assess efficacy. 1

Before initiating macrolide therapy:

• Perform ECG to assess QTc interval (contraindicated if QTc >450 ms for men or >470 ms for women) 1
• Measure baseline liver function tests 1

Use bronchodilators (β-agonists and antimuscarinic agents) if significant breathlessness is present, particularly with chronic obstructive airflow limitation. 3, 6

Important Treatment Caveats

Do NOT use recombinant human DNase (dornase alfa) in non-CF bronchiectasis, as it may worsen outcomes. 3

Do NOT routinely use inhaled corticosteroids unless comorbid asthma or COPD is present. 3, 6

Do NOT use long-term oral corticosteroids without specific indications (ABPA, chronic asthma, COPD, inflammatory bowel disease). 3

Immunizations

Annual influenza vaccination is mandatory for all bronchiectasis patients. 3

Pneumococcal vaccination is recommended for all bronchiectasis patients. 3

Monitoring and Follow-Up

Annual assessments are recommended for mild disease, with more frequent monitoring if disease progresses. 3 Regular sputum culture and sensitivity monitoring should be performed. 3

Prognosis and Complications

Exacerbations are associated with increased inflammation, accelerated lung function decline, and higher mortality, with up to 30% mortality at 1-year follow-up after an exacerbation, particularly in the presence of COPD. 2 Mortality is higher for those with frequent and severe exacerbations, Pseudomonas aeruginosa infection, and comorbidities such as COPD. 6

Lung transplant may be considered for patients with severely impaired pulmonary function or frequent exacerbations despite optimal medical management. 6