bronchiectasis
BRONCHIECTASIS
Bronchiectasis is an irreversible pathologic dilatation or ectasia of the bronchi due to repeated airway infection and inflammation.
It enhances susceptibility to bronchial infection and increases inflammatory reaction which causes further lung damage.
Classic symptoms of of bronchiectasis are cough with chronic sputum production along with recurring infective exacerbations and hemoptysis.

Diagnosis

  • Diagnosis is based on clinical history of daily viscid sputum production & characteristic CT findings
    • Rare variant: Dry bronchiectasis (Bronchiectasis sicca) which manifests by episodic hemoptysis w/ no sputum production [usually a sequela of tuberculosis (TB)]

History

  • Assess the amount of sputum production w/in 24 hr & the frequency of exacerbation over the last 12 mth
  • Identify possible underlying etiologies that may have caused bronchiectasis
Primary Infections
  • Necrotizing infections that are not treated properly or not treated at all is a common cause of bronchiectasis in developing countries
  • Typical offending organisms include Klebsiella sp, Staphylococcus aureus, Mycobacterium tuberculosis, Mycoplasma pneumoniae, non-tuberculous mycobacteria, measles, pertussis, influenza, herpes simplex & certain types of adenovirus
    • Mycobacterium avium complex (MAC) has propensity to occur in patients who are immunocompetent
 Bronchial Obstruction
  • Focal post-obstructive bronchiectasis may occur in endobronchial tumors, broncholithiasis, bronchial stenosis from infections, encroachment of hilar lymph nodes & foreign body aspiration
  • In adults, foreign body aspiration may occur w/ altered mental status & when food is not chewed
    • Chicken bone fragments may be the cause of lower resp tract obstruction in Chinese people from eating cooked meat on the bone
Cystic Fibrosis (CF)
  • Typically rare in non-white races
  • Autosomal recessive multisystem disorder affecting the chloride transport system in exocrine tissues
  • Bronchiectasis is the major pulmonary finding of this disease
  • Bronchiectasis due to this disease occurs secondary to mucous plugged proximal airways & chronic resp infection
Young Syndrome
  • Syndrome clinically similar to CF
  • Patients have the triad of bronchiectasis, sinusitis & obstructive azoospermia
Ciliary Disorders
  • Primary ciliary dyskinesia is rare but can cause poor mucociliary clearance, recurrent resp infections & bronchiectasis
  • Kartagener’s syndrome which is characterized by situs inversus, bronchiectasis, chronic sinusitis w/ immotile cilia
Allergic Bronchopulmonary Aspergillosis (ABPA)
  • Hypersensitivity reaction to inhaled Aspergillus antigen that is characterized by bronchospasm, bronchiectasis, & immunologic evidence of a reaction to Aspergillus sp
  • Bronchiectasis is secondary to airway plugs of viscid secretions containing hyphae of Aspergillus sp
  • CT scan of chest reveals central airway bronchiectasis
Immunodeficiency states
  • Congenital or acquired immunodeficiency usually present w/ repeated sinus or pulmonary infections
  • Bronchiectasis in AIDS has occurred w/ & w/o obvious preceding pulmonary infections
Alpha1- Antitrypsin Deficiency & Rheumatic Diseases
  • Pathogenesis of bronchiectasis in these conditions is unclear & may represent only coincidental findings
Traction Bronchiectasis
  • Distortion of the airways secondary to distortion of the lung parenchyma from pulmonary fibrosis

Physical Examination

  • General findings: Cyanosis, plethora, wasting, wt loss & finger clubbing
  • In advanced disease, cor pulmonale may be observed
  • Physical findings are nonspecific but persistent coarse crackles over any part of the lungs suggests bronchiectasis
  • Nasal polyps & sinusitis may be present

Laboratory Tests

Sputum Analysis
  • Sputum culture & smear for bacteria, mycobacteria & fungi
    • Reinforces the diagnosis of bronchiectasis & adds significance to the information regarding the etiologies & treatment
    • Frequently positive for Haemophilus influenza, Pseudomonas aeruginosa, Streptococcus pneumoniae
Pulmonary Function Tests
  • May reflect underlying diseases
  • May be normal in localized & mild bronchiectasis
  • The most common abnormality is an obstructive & restrictive airway defect, especially in patients w/ more severe disease
  • Useful in obtaining a functional assessment of the patient
Other Diagnostic Studies to Confirm Underlying Etiologies
  • Recommended in patients w/ no evident cause of the disease; results may assist in the management & prognosis of the patient
  • The following diagnostic tests may be considered in the appropriate clinical setting:
    • Pilocarpine iontophoresis (sweat test) for cystic fibrosis
    • Rheumatoid factor for rheumatoid diseases
    • Aspergillus precipitins/antibody for allergic bronchopulmonary aspergillosis (ABPA)
  • Flexible bronchoscopy to rule out obstruction by foreign bodies, etc

Imaging

Chest X-ray
  • The following findings are suspicious but non-diagnostic findings:
    • Linear atelectasis, dilated & thickened airways (tram or parallel lines; ring shadows on cross section) & irregular opacities representing mucopurulent plugs

High Resolution CT (HRCT) Scan

  • HRCT is the defining test for bronchiectasis, w/ sensitivity & specificity of 98% & 99%, respectively
  • Assess severity of the disease by measuring the number of bronchopulmonary segments affected or percentage of the lobes involved
  • Indications
    • There are suspicious clinical findings but a relatively normal chest radiograph
    • Abnormal chest radiograph & bronchiectasis is suspected
    • Management decisions must be made depending on extent of bronchiectasis
    • Presence of confounding diseases need to be defined
  • Findings
    • Diagnostic features:
      • Lacks normal tapering of bronchi
      • Bronchial diameter is larger than the accompanying pulmonary artery (called signet ring sign)
      • Peripheral airways are seen w/in 1 cm of the costal pleura
    • Other nonspecific findings:
      • Bronchial wall thickening
      • Dilated airways w/ air-fluid levels
      • Mucopurulent plugs or debris accompanied by post-obstructive air trapping
      • “Tree-in-bud” pattern when small airways are affected
      • More destructive bronchiectasis shows cysts on the bronchial wall
      • Consolidation of a segment or lobe maybe seen
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