Makindo Medical Notes

💡 Note: Treat with systemic steroids + antifungal therapy (e.g., Itraconazole). 🔬 Monitor progress with **serial total serum IgE** levels.

📖 About

• Allergic Bronchopulmonary Aspergillosis (ABPA) is a hypersensitivity reaction to the fungus Aspergillus fumigatus.
• 🚫 It is not an invasive infection — rather, it’s an exaggerated allergic immune response.
• 🧪 The immune mechanism involves:
  • Type I (IgE-mediated immediate hypersensitivity)
  • Type III (immune complex–mediated inflammation)

🧬 Aetiology & Pathophysiology

• Aspergillus spores are widespread in the environment (soil, compost, decaying vegetation).
• 🌬️ About 10% of asthmatics (especially steroid-dependent) may develop ABPA.
• Immune cascade:
  • CD4+ Th2 cells release IL-4/IL-5 → ⬆ IgE + eosinophilia 🧾
  • IL-8 recruits neutrophils → airway inflammation + tissue injury
• Patients with cystic fibrosis (CF) are particularly prone due to mucus stasis and chronic colonisation.

🩺 Clinical Features

• Asthma-like symptoms: wheeze, breathlessness, chronic cough 😮‍💨
• Systemic: malaise, fever during exacerbations 🌡️
• Recurrent exacerbations with **thick mucus plugging** (sometimes expectorated).
• ⚠️ Poor asthma control → frequent steroid dependency.

🔍 Investigations

• Bloods:
  • ⬆ Total serum IgE (often >1000 IU/mL)
  • ⬆ Eosinophils
  • Specific IgE to A. fumigatus
• Sputum: May show Aspergillus hyphae.
• Skin-prick test: Positive to A. fumigatus.
• CXR/HRCT: Transient opacities, central bronchiectasis, upper-lobe fibrosis, mucus impaction (“finger-in-glove” sign 🖐️).

💊 Management

• Asthma optimisation: Continue bronchodilators + inhaled corticosteroids.
• Systemic steroids: Prednisolone 40–50 mg/day tapered over weeks → improves symptoms + lung function.
• Mucus clearance: Steroid therapy often leads to expectoration. Bronchoscopy may occasionally be required.
• Antifungal therapy: Itraconazole (200 mg BD) may reduce fungal burden + steroid dependence.
• Monitoring: Regular serum IgE tracking – rising levels suggest relapse 🔄.

⚠️ Teaching Pearls / Pitfalls

• Distinguish ABPA from invasive aspergillosis (ABPA is immune-mediated, not infective).
• Bronchiectasis is usually **central** rather than peripheral in ABPA – a key imaging clue 🔎.
• Relapses are common → requires long-term follow-up with both respiratory + immunology input.

📚 References

• NICE Asthma Guidelines
• Thorax Journal – ABPA Research