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Internal Medicine

Bronchiectasis

Permanent dilation of bronchi & bronchioles (due to infections and inflammation that destroy the muscle and elastic tissue supporting the airway).

Chronic lung disease characterized by persistent and lifelong widening of the bronchial airways and weakening of the function mucociliary transport mechanism owing to repeated infection contributing to bacterial invasion and mucus pooling throughout the bronchial tree.

Figure A shows a cross-section of the lungs with normal airways and widened airways. Figure B shows a cross-section of a normal airway. Figure C shows a cross-section of an airway with bronchiectasis. | National Heart Lung and Blood Institute, Public Domain, https://commons.wikimedia.org/w/index.php?curid=29583169

Etiopathogenesis

The condition is characterized by a vicious cycle of persistent bacterial infection and excessive neutrophilic inflammation owing to impairment of airway defence mechanisms.

bronchiectasis-pathogenesis-and-clinical-findings
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Risk factors:

Risk factors for bronchiectasis are related mainly to cause of the disease, with prevalence higher in patients with autoimmune or connective tissue diseases, chronic infections such as HIV and chronic lung disease such as chronic obstructive pulmonary disease (COPD) and asthma

Microbiology:

A large number of different pathogens have been isolated in studies of microbiologic flora in bronchiectasis. There is often significant variation between different locations. An important finding of bronchiectasis is that there appears to be a change in microbial flora with severity of disease. Typically subjects with the best-preserved lung function are most likely to have no pathogenic bacteria isolated. As lung function declines H. influenzae becomes predominant and finally in patients with the most severe disease the usual pathogen isolated is P. aeruginosa.
  • Nontypeable Haemophilus influenzae (NTHi): M/C pathogen, 29%–70%
  • Pseudomonas aeruginosa: #2 M/C, 12%–31%. P. aeruginosa has the capacity to form biofilms, particularly in advanced disease and form an impenetrable matrix, shielding it from the effects of the immune system and antibiotics and allowing the bacterial infection to cause severe damage to the underlying lung
  • Other microbes: Nontuberculous mycobacterial infection (2-10%), Streptococcus pneumoniae

Muco-ciliary clearance:

Muco-ciliary clearance is a key defence mechanism against pulmonary infection. Its compromise is important in the development of the vicious cycle of bronchiectasis
  • Cystic fibrosis: Recurrent lower respiratory infections associated with malabsorption. These patients have history of meconium ileus during neonatal period
  • Young syndrome: Sinusitis, bronchiectasis and azoospermia
  • Primary ciliary dyskinesia (PCD) “Kartenger Syndrome”: Bronchiectasis, situs inversus and sinusitis
  • Young’s syndrome: Primary defect of mucous function leading to sinusitis, bronchiectasis and azoospermia

Extremes of age:

immune system is less effective in young children and elderly adults which results in an increased incidence of infection in these two groups. Bronchiectasis has most commonly been described as commencing in childhood, particularly in the first five years of life, with chronic productive cough and unresolved infection
Change in severity of symptoms over time in those with childhood-onset bronchiectasis. A common finding in subjects whose symptoms began in childhood is improvement in late adolescence and then deterioration again from about the age of 50 years. | King P. T. (2009). The pathophysiology of bronchiectasis. International journal of chronic obstructive pulmonary disease, 4, 411–419. https://doi.org/10.2147/copd.s6133

Presentation

History of a long-standing cough with purulence is typical of bronchiectasis. Patients may report repetitive pulmonary infections that require antibiotics over several years. Often patients are diagnosed after many years of symptoms when a chronic cough or hemoptysis becomes debilitating.

  • Progressive dyspnea, intermittent wheezing
  • Pleuritic chest pain
  • Associated fatigue and weight loss
  • Hemoptysis: Mild (blood flecks in sputum) and occasionally life-threatening.

Common clinical findings:

  • Digital clubbing (2% to 3%), cyanosis, plethora
  • Wasting and weight loss
  • Local chest examination:  Most commonly crackles and wheezes on auscultation.
    • Crackles: 75%, usually bi-basal.
    • Wheezing: 22% (wheezing may be due to airflow obstruction from secretions)

Specific Clinical Features:

  • Connective tissue diseases: Arthritis Sicca syndrome
  • ABPA: Prominent wheezing
  • Bronchial obstruction: localized wheezing
  • PCD, CF, Young Syndrome: Recurrent sinus disease, infertility
  • Features of acute exacerbation of bronchiectasis: Change in sputum production, increased dyspnea, increased cough, fever, increased wheezing, and reduced pulmonary function.

Diagnosis

British Thoracic Society (BTS) recommendations:

  • Immunoglobulin tests (IgA, IgM, IgG, and IgE)
  • ABPA tests :Specific IgE to Aspergillus, IgG to Aspergillus, and eosinophil count
  • Sputum culture: Exclude nontuberculous mycobacteria (NTM)
  • Assessment of autoantibodies
  • Cystic fibrosis (CF) diagnosis (recommended for patients aged younger than 40 years or with recurrent Pseudomonas aeruginosa and Staphylococcus aureus isolation, or upper lobe predominant disease irrespective of age): Sweat test and/or screening for common CF mutations) is
  • HIV (if indicated): Alpha-1 Antitrypsin level, Ciliary function analysis, and Serology

High-resolution CT scan (HRCT)

Gold standard for confirming the diagnosis, ideally done when the patient is clinically stable.
  • Signet ring sign: Dilated airway lies adjacent to a pulmonary artery branch giving the appearance of a ring (internal bronchial diameter greater than that of the adjacent pulmonary artery).
  • Tree-in-bud pattern: Due to thickened secretions
  • Tram track sign: Lack of peripheral tapering of the bronchus
  • String of beads appearance: Alternate dilatation and constriction in varicose bronchiectasis
  • Cluster of grapes appearance: Cysts emanating from the bronchial wall as cystic bronchiectasis
bronchiectasisxray
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640px-ct_scan_in_usual_interstitial_pneumonia_28uip29
CT scan in usual interstitial pneumonia (UIP). There is interstitial thickening, architectural distortion, honeycombing and bronchiectasis. | Yale Rosen (USA) – UIP (Usual interstitial pneumonia)-CT scan, Image contributed by Darel Heitkamp, MD.Uploaded by CFCF, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=31127997

Management

Bronchiectasis is treatable but rarely curable. Identifying and treating the underlying cause is the first step in management

Mucus clearance:

Improving tracheobronchial clearance is the mainstay of therapy in bronchiectasis
  • Postural drainage: Uppermost lobe drained for a minimum of 5-10 minutes twice a day
  • ‘Active cycle of breathing’ technique: Deep breathing followed by forced expiratory maneuvers is of help in allowing secretions in the dilated bronchi to gravitate towards the trachea, from which vigorous coughing can clear them.
  • Percussion of chest wall with cupped hands or with mechanical devices: Dislodge sputum

Antibiotic therapy:

Antibiotic regimen is based on culture and sensitivity tests and severity of infection
  • Mild bronchiectasis: Oral antibiotics
  • Empirical treatment: Amoxicillin, co-amoxiclav, or macrolides (2 weeks)
    • H. influenza: Oral amoxicillin 1 gm (2 weeks)
    • Pseudomonas-colonized: Ciprofloxacin 750 mg (2 weeks)
  • Moderate-to-severe bronchiectasis: Parenteral antibiotics
    • Empirical: Aminoglycoside (gentamicin, tobramycin), and antipseudomonal synthetic penicillin, a third-generation cephalosporin, or a fluoroquinolone
    • Pseudomonas: Antipseudomonal antibiotics, nebulized colistin for 3 months, or nebulized colistin for 3 months with an additional 4 weeks of oral ciprofloxacin (2 weeks)

Airflow maintainance:

In patients with airflow obstruction (COPD & asthma), inhaled bronchodilators and corticosteroids should be used to enhance airway patency.

Lifestyle modifications:

  • Stop smoking
  • Vaccination against influenza and pneumococcal disease recommended.

Adjunctive Surgical Treatment:

Surgery is only indicated in a small proportion of cases. These are usually young patients in whom the bronchiectasis is unilateral and confined to a single lobe or segment, as demonstrated by CT. It is also performed in some cases with advanced/complicated disease.
  • Single- or double-lung transplantation has been used as a treatment of severe bronchiectasis, predominantly when related to CF. In general, consider patients with CF and bronchiectasis for lung transplantation when FEV falls below 30% of the predicted value. Female patients and younger patients may need to be considered sooner
  • Massive hemoptysis: Bronchial artery embolization and/or surgery is first-line therapy for the management of massive hemoptysis.

Summary

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