Allergic Bronchopulmonary Aspergillosis — SAQ

Questions and marking scheme

Marking rule: award only the ten numbered one-mark atoms below. Each atom is 1 mark. Award no half marks and no cross-credit between parts.^[1]

a) Diagnose and apply the revised criteria. (2 marks)

1. Diagnosis and radiological class — 1 mark: acute newly diagnosed ABPA with mucus plugging (ABPA-MP); non-HAM mucus plugs classify disease as MP even when bronchiectasis coexists.^[1]
2. Criteria — 1 mark: she has a compatible predisposing condition, both essentials (A. fumigatus-specific IgE at least 0.35 kUA/L and total IgE at least 500 IU/mL) and all three supportive components: raised A. fumigatus-IgG, eosinophils at least 500/microL and compatible CT imaging. Any two supportive components are sufficient.^[1]

b) State two diagnostic corrections introduced by the 2024 revision. (2 marks)

3. Host correction — 1 mark: asthma and cystic fibrosis are no longer obligatory; asthma, CF, COPD or bronchiectasis, or a compatible clinico-radiological presentation, can be the entry condition.^[1]
4. Test correction — 1 mark: serum A. fumigatus-specific IgE is preferred; a skin test is only an alternative when specific IgE is unavailable, and a negative skin test does not exclude ABPA. HAM, if present, is pathognomonic.^[1]

c) Prescribe both accepted first-line monotherapy regimens and explain why routine combination therapy is wrong here. (3 marks)

5. Prednisolone regimen — 1 mark: prescribe prednisolone 0.5 mg/kg/day orally for 2–4 weeks, then taper to complete about 4 months; one validated low-dose schedule uses 0.5 mg/kg/day for 2 weeks, the same dose on alternate days for 8 weeks, then reduces by 5 mg every 2 weeks over 3–5 months.^[1][2]
6. Alternative monotherapy — 1 mark: if glucocorticoids are contraindicated or an azole is preferred after shared decision-making, use conventional itraconazole 400 mg/day orally in two divided doses with meals for 4 months, with liver tests and trough TDM at about 2 weeks and 3 months; target at least 0.5 mg/L.^[1][3]
7. No routine combination — 1 mark: acute first-line therapy is prednisolone or itraconazole, not both routinely; reserve the combination for recurrent ABPA exacerbations, defined for this treatment decision as at least two in the preceding 1–2 years, especially with extensive bronchiectasis.^[1][4]

d) Define response and distinguish a later ABPA exacerbation from asthma exacerbation. (2 marks)

8. Response — 1 mark: at 8 weeks, symptoms must improve by at least 50%, plus either radiological opacities improve by over 50% or total IgE falls by at least 20%. Assess with symptoms, total IgE and chest radiograph at 8–12 weeks.^[1]
9. Exacerbation boundary — 1 mark: ABPA exacerbation requires sustained clinical worsening for over 14 days or radiological worsening and total IgE rise at least 50% from the stable value, after excluding other causes; an asthma exacerbation lasts at least 48 hours without ABPA immunological or radiological deterioration.^[1]

e) Name one dangerous itraconazole interaction relevant to this patient. (1 mark)

10. Interaction — 1 mark: itraconazole can markedly increase exposure to inhaled budesonide or fluticasone through CYP3A4 inhibition, causing iatrogenic Cushing syndrome and adrenal suppression; review the full medication list and also avoid use in ventricular dysfunction/heart failure because of negative inotropy.^[1]

Total: 10 marks = 2 + 2 + 3 + 2 + 1. No half marks; no cross-credit.^[1]