Bronchiectasis

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Basics

Description

  • Bronchiectasis is an irreversible dilatation of ≥1 airways accompanied by recurrent transmural bronchial infection/inflammation and chronic mucopurulent sputum production.
  • It may be focal or diffused.

Epidemiology

  • Predominant age: most commonly presents in 6th decade of life
  • Predominant sex: female > male (1)

Incidence
  • Incidence has decreased in the United States for two reasons:
    • Widespread childhood vaccination against pertussis
    • Effective treatment of childhood respiratory infections with antibiotics
  • Among children, incidence may be higher in indigenous or socioeconomically disadvantaged group (2).
Prevalence
  • In the United States, prevalence estimated to be 139/100,000 (3)
  • Higher among women versus men (180 vs. 95/100,000) and to increase substantially with age (from 7/100,000 to 812/100,000 aged 34 and ≥75 years (3)

Etiology and Pathophysiology

  • Frequently idiopathic
  • Chronic infections (PTB), autoimmune disease, genetic causes (cystic fibrosis (CF)), chronic obstructive pulmonary disease (COPD), connective tissue disease, allergic bronchopulmonary aspergillosis (ABPA) (4)
  • Vicious circle hypothesis: Transmural infection, generally by bacterial organisms, causes inflammation and obstruction of airways. Damaged airways and dysfunctional cilia foster bacterial colonization, which leads to further inflammation and obstruction.

Risk Factors

  • Nontuberculous mycobacterial infection is both a cause and a complication of non-CF bronchiectasis.
  • Severe respiratory infection in childhood (measles, adenovirus, influenza, pertussis, or bronchiolitis)
  • Systemic diseases (e.g., rheumatoid arthritis and inflammatory bowel disease)
  • Chronic rhinosinusitis
  • Recurrent pneumonia
  • Aspirated foreign body
  • Immunodeficiency
  • Congenital abnormalities

General Prevention

  • Routine immunizations against pertussis, measles, Haemophilus influenzae type B, influenza, and pneumococcal pneumonia
  • Genetic counseling if congenital condition is etiology
  • Smoking cessation

Commonly Associated Conditions

  • Mucociliary clearance defects
    • Primary ciliary dyskinesia
    • Young syndrome (secondary ciliary dyskinesia)
    • Kartagener syndrome
  • Other congenital conditions
    • α1-Antitrypsin deficiency
    • Marfan syndrome
    • Cartilage deficiency (Williams-Campbell syndrome)
  • COPD
  • Pulmonary fibrosis, causing traction bronchiectasis
  • Postinfectious conditions
    • Bacteria (H. influenzae and Pseudomonas aeruginosa)
    • Mycobacterial infections (tuberculosis [TB] and Mycobacterium avium complex [MAC])
    • Whooping cough
    • Aspergillus species
    • Viral (HIV, adenovirus, measles, influenza virus)
  • Immunodeficient conditions
    • Primary: hypogammaglobulinemia
    • Secondary: ABPA, posttransplantation
    • Sequelae of toxic inhalation or aspiration (e.g., chlorine, luminal foreign body)
  • Rheumatic/chronic inflammatory conditions
    • Rheumatoid arthritis
    • Sjögren syndrome
    • Systemic lupus erythematosus
    • Inflammatory bowel disease
  • Miscellaneous
    • Yellow nail syndrome

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Basics

Description

  • Bronchiectasis is an irreversible dilatation of ≥1 airways accompanied by recurrent transmural bronchial infection/inflammation and chronic mucopurulent sputum production.
  • It may be focal or diffused.

Epidemiology

  • Predominant age: most commonly presents in 6th decade of life
  • Predominant sex: female > male (1)

Incidence
  • Incidence has decreased in the United States for two reasons:
    • Widespread childhood vaccination against pertussis
    • Effective treatment of childhood respiratory infections with antibiotics
  • Among children, incidence may be higher in indigenous or socioeconomically disadvantaged group (2).
Prevalence
  • In the United States, prevalence estimated to be 139/100,000 (3)
  • Higher among women versus men (180 vs. 95/100,000) and to increase substantially with age (from 7/100,000 to 812/100,000 aged 34 and ≥75 years (3)

Etiology and Pathophysiology

  • Frequently idiopathic
  • Chronic infections (PTB), autoimmune disease, genetic causes (cystic fibrosis (CF)), chronic obstructive pulmonary disease (COPD), connective tissue disease, allergic bronchopulmonary aspergillosis (ABPA) (4)
  • Vicious circle hypothesis: Transmural infection, generally by bacterial organisms, causes inflammation and obstruction of airways. Damaged airways and dysfunctional cilia foster bacterial colonization, which leads to further inflammation and obstruction.

Risk Factors

  • Nontuberculous mycobacterial infection is both a cause and a complication of non-CF bronchiectasis.
  • Severe respiratory infection in childhood (measles, adenovirus, influenza, pertussis, or bronchiolitis)
  • Systemic diseases (e.g., rheumatoid arthritis and inflammatory bowel disease)
  • Chronic rhinosinusitis
  • Recurrent pneumonia
  • Aspirated foreign body
  • Immunodeficiency
  • Congenital abnormalities

General Prevention

  • Routine immunizations against pertussis, measles, Haemophilus influenzae type B, influenza, and pneumococcal pneumonia
  • Genetic counseling if congenital condition is etiology
  • Smoking cessation

Commonly Associated Conditions

  • Mucociliary clearance defects
    • Primary ciliary dyskinesia
    • Young syndrome (secondary ciliary dyskinesia)
    • Kartagener syndrome
  • Other congenital conditions
    • α1-Antitrypsin deficiency
    • Marfan syndrome
    • Cartilage deficiency (Williams-Campbell syndrome)
  • COPD
  • Pulmonary fibrosis, causing traction bronchiectasis
  • Postinfectious conditions
    • Bacteria (H. influenzae and Pseudomonas aeruginosa)
    • Mycobacterial infections (tuberculosis [TB] and Mycobacterium avium complex [MAC])
    • Whooping cough
    • Aspergillus species
    • Viral (HIV, adenovirus, measles, influenza virus)
  • Immunodeficient conditions
    • Primary: hypogammaglobulinemia
    • Secondary: ABPA, posttransplantation
    • Sequelae of toxic inhalation or aspiration (e.g., chlorine, luminal foreign body)
  • Rheumatic/chronic inflammatory conditions
    • Rheumatoid arthritis
    • Sjögren syndrome
    • Systemic lupus erythematosus
    • Inflammatory bowel disease
  • Miscellaneous
    • Yellow nail syndrome

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