Bronchiectasis and Cystic Fibrosis

Bronchiectasis - Widened Airways Woes

Irreversible bronchial dilatation from chronic inflammation and airway wall destruction.

• Pathophysiology: Vicious cycle: Insult → Inflammation → Airway Damage/Dilatation → Impaired Clearance → Colonization/Recurrent Infection.

• Etiologies:
  • Post-infectious: TB (India), severe pneumonia (measles, pertussis).
  • Congenital/Genetic: Cystic Fibrosis (CF), Primary Ciliary Dyskinesia (PCD - Kartagener's: situs inversus, sinusitis, bronchiectasis).
  • Immunodeficiency: e.g., Hypogammaglobulinemia.
  • Allergic Bronchopulmonary Aspergillosis (ABPA).
  • Airway Obstruction: Tumor, foreign body. Idiopathic.
• Clinical Features:
  • Chronic productive cough: Copious, purulent, foul sputum (may form 3 layers).
  • Hemoptysis: Recurrent, can be massive.
  • Dyspnea, pleuritic pain, fatigue.
  • Signs: Persistent coarse crackles (bibasilar), clubbing.
• Diagnosis:
  • HRCT Chest (Gold Standard):
    • Bronchial diameter > adjacent artery ("Signet Ring" sign).
    • No bronchial tapering ("Tram-track" lines); bronchi visible near pleura (within 1 cm).
    • Wall thickening, mucoid impaction, cysts.
  • Sputum: Microscopy, culture (H. influenzae, P. aeruginosa). AFB stain.
  • PFTs: Often obstructive (↓FEV1, ↓FEV1/FVC < 0.7).
• Management:
  • Treat underlying cause. Airway clearance (physiotherapy, PEP devices).
  • Antibiotics: Acute exacerbations (culture-guided); long-term (e.g., azithromycin) if ≥3/year or P. aeruginosa.
  • Bronchodilators, mucolytics (e.g., hypertonic saline).
  • Surgery (lobectomy) for localized disease, severe symptoms, or massive hemoptysis.

  ⭐ Pseudomonas aeruginosa colonization is common in advanced bronchiectasis, linked to ↑exacerbations, ↑severity & accelerated lung function decline.

Cystic Fibrosis - Salty Secretions Story

• Etiology: Autosomal recessive; CFTR gene (Chr 7, ΔF508 commonest). Defective Cl⁻ channel → viscous secretions in exocrine glands, impaired mucociliary clearance.
• 📌 Mnemonic "CF PANCREAS": Chronic cough, Failure to thrive, Pancreatic insufficiency, Alkalosis (metabolic), Nasal polyps, Clubbing, Rectal prolapse, Electrolytes in sweat (↑Na⁺, Cl⁻), Absence of vas deferens, Sputum (mucoid, Pseudomonas).
• Clinical Features:
  • Pulmonary: Recurrent infections (S. aureus, P. aeruginosa), bronchiectasis, chronic cough, hemoptysis, digital clubbing.
  • Pancreatic: Exocrine insufficiency (85-90%) → malabsorption (steatorrhea, ADEK vitamin deficiency), failure to thrive. Cystic Fibrosis-Related Diabetes (CFRD).
  • GI: Meconium ileus (newborns), Distal Intestinal Obstruction Syndrome (DIOS).
  • Sweat Glands: ↑NaCl in sweat ("salty baby" kiss).
  • Reproductive: Male infertility (95%, Congenital Bilateral Absence of Vas Deferens - CBAVD).
• Diagnosis:
  • Newborn screening: Immunoreactive Trypsinogen (IRT).
  • Sweat Chloride Test (Pilocarpine iontophoresis):
    • Positive: > 60 mmol/L (on 2 occasions).
    • Intermediate: 30-59 mmol/L (infants <6mo), 40-59 mmol/L (older individuals).
  • Genetic testing: CFTR mutation analysis (confirmatory).
• Management: Multidisciplinary approach.
  • Airway clearance: Chest physiotherapy, dornase alfa (DNase).
  • Antibiotics: For infections/exacerbations (e.g., inhaled tobramycin for Pseudomonas). Chronic azithromycin (anti-inflammatory).
  • Pancreatic Enzyme Replacement Therapy (PERT), ADEK vitamin supplementation.
  • CFTR modulators (e.g., elexacaftor/tezacaftor/ivacaftor).
  • Lung transplantation for end-stage disease.

⭐ Pseudomonas aeruginosa (especially mucoid strains) colonization in CF patients is a major cause of morbidity and mortality, leading to accelerated lung function decline and increased frequency of exacerbations.

High‑Yield Points - ⚡ Biggest Takeaways

• Bronchiectasis: Permanent bronchial dilation, chronic productive cough (purulent sputum), HRCT "signet ring" sign.
• Cystic Fibrosis (CF): Autosomal recessive, CFTR gene mutation (e.g., ΔF508), causing thick, viscous secretions.
• CF impacts: Recurrent Pseudomonas lung infections, pancreatic insufficiency, meconium ileus in newborns.
• CF diagnosis: Elevated sweat chloride test (>60 mEq/L) is key.
• Kartagener's syndrome: Triad of bronchiectasis, situs inversus, chronic sinusitis.