Bronchiectasis

 

Epidemiology:

    • Associated with a variety of conditions:
      • Hereditary:
        • cystic fibrosis
        • intralobar sequestration of the lung
        • immunodeficiency
        • primary ciliary dyskinesia
        • Kartagener syndrome
      • Postinfectious:
        • Necrotizing pneumonia
          • TB, Staph. aureus, H. influenzae, Pseudomonas
          • Viruses (adenovirus, influenza virus, HIV)
          • Fungi (Aspergillus)
      • Bronchial obstruction
        • Tumour
        • Foreign bodies
        • Mucous
      • Others:
        • RA
        • SLE
        • IBD
        • Post-transplant (lung or bone marrow – GVHD)

 

Common sites:

    •  

 

Gross features:

    • lower lobes > upper lobes
    • vertical air passages particularly involved
    • distal bronchi and bronchioles most involved
    • may be sharply localized to a single segment when associated with tumour or foreign body
    • dilated airways
      • cylindrical, fusiform, or saccular
      • can usually be followed to the pleural surfaces
        • normally can’t see bronchioles beyond 2-3cm from pleura
      • cysts filled with mucopurulent secretions

 

Histologic features:

    • damage to airway walls
      • destruction of smooth muscle and elastic tissue
      • fibrosis
      • dilation
    • acute and chronic inflammatory exudation within walls of bronchi and bronchioles
    • desquamation of the lining epithelium
    • areas of necrotizing ulceration
    • pseudostratification of the columnar cells maybe
    • squamous metaplasia maybe
    • abscess sometimes with complete destruction of bronchial or bronchiolar walls
    • fibrosis of bronchial and bronchiolar walls and peribronchiolar areas
      • bronchiolitis obliterans in severe cases

 

Immunophenotype:

Marker:

Sensitivity:

Specificity:

 

 

 

 

Molecular features:

    •  

 

Other features:

    • permanent dilation of bronchi and bronchioles caused by destructikon of the muscle and elastic tissue, resulting from or associated with chronic necrotizing infections
    • obstruction and infection are most important drivers
    • flora involved:
      • staph
      • strep
      • pneumococci
      • enteric
      • anaerobic
      • microaerophilic
      • Haemophilus influenza
      • Pseudomonas aeruginosa
      • Aspergillus in ABPA
    • Complications:
      • Cor pulmonale
      • Metastatic brain abscesses
      • amyloidosis

 

References:

    • Robbins 2005