Abpa for md exams 10 marks answer from fishman and murray and recent isham guidelines 2026
Reading File
Finding Sources
Searching PubMed
allergic bronchopulmonary aspergillosis diagnosis treatment guidelines
Searching the Web
ISHAM ABPA guidelines 2026 allergic bronchopulmonary aspergillosis
Reading File
Reading Article
Reading Web Page
ABPA diagnosis classification treatment ISHAM guidelines 2024
Reading File
Finding Sources
Reading File
I have extensive material now from Fishman's and the ISHAM 2024 guidelines. I have enough to write a comprehensive 10-mark MD exam answer. Let me compile it.
Allergic Bronchopulmonary Aspergillosis (ABPA) - 10 Marks
Definition and Introduction
Allergic bronchopulmonary aspergillosis (ABPA) is a complex hypersensitivity disorder of the lung caused by an aberrant immunological response to colonization by Aspergillus fumigatus (occasionally other fungi). It occurs almost exclusively in patients with chronic asthma or cystic fibrosis (CF), affecting 7-14% of poorly controlled asthmatic adults and 7-9% of CF patients.
(Fishman's Pulmonary Diseases and Disorders, Ch. 132)
Pathogenesis / Immunopathology
ABPA develops in genetically susceptible individuals due to excessive A. fumigatus-specific Th2 CD4+ lymphocyte activity. Key predisposing genetic factors include:
- HLA-DR2 and HLA-DR5 alleles
- CFTR gene mutations (in CF patients)
- Polymorphisms in SP-A2 collectin and mannose-binding lectins
- ZNF77 transcription factor polymorphisms impairing epithelial integrity
The sequence of immunopathology proceeds as follows:
- Inhaled A. fumigatus conidia germinate in mucus plugs, releasing proteases that breach the epithelial barrier
- IgE on mast cells recognizes fungal antigens → mast cell degranulation → vasodilatation and increased vascular permeability
- Serum anti-Aspergillus IgG enters airways → combines with antigens to form IgG immune complexes
- Immune complexes activate complement cascade → pulmonary inflammation and structural damage
- A combined Type I (IgE-mediated) + Type III (immune complex) + Type IV (cell-mediated) hypersensitivity reaction occurs
(Fishman's Pulmonary Diseases and Disorders, pp. 2323-2324)
Clinical Features
| Feature | Description |
|---|---|
| Episodic wheezing | Often steroid-dependent asthma |
| Low-grade fever and malaise | Common during exacerbations |
| Cough with brown/dark mucus plugs | Characteristic cylindrical branching mucus casts (see below) |
| Sputum and blood eosinophilia | Blood eosinophilia >500 cells/µL |
| Hemoptysis and clubbing | In advanced disease |
| Recurrent pneumonias | Antibiotic-refractory |
Mucus plugs are tapering, cylindrical, branching structures reflecting the shape of parent bronchi. As disease progresses, central bronchiectasis becomes the dominant feature, leading to chronic bronchorrhea and irreversible structural damage.
In CF patients, ABPA may manifest with hemoptysis and can be complicated by pneumothorax.
(Fishman's Pulmonary Diseases and Disorders, p. 2324)
Radiological Features
Chest X-Ray:
- "Ring sign" - bronchial wall thickening
- "Tram lines" / "parallel shadows" - peribronchial cuffing indicating bronchiectasis
- "Finger-in-glove" opacity - mucoid impaction of dilated bronchi
- Fleeting infiltrates (upper lobe predominance)
- Late findings: cavitation, contracted upper lobes, honeycomb fibrosis
HRCT (more sensitive):
- Central (proximal) bronchiectasis - hallmark finding; normal filling of bronchi distal to the saccular lesion
- Varicose/cystic bronchiectasis of segmental and subsegmental bronchi (90% in ABPA vs. 30% in asthma alone)
- Mucoid impaction (67% vs. 4% in asthma)
- Centrilobular nodules and tree-in-bud opacities (93% vs. 28%)
- High-attenuation mucus (HAM) plugs - due to dystrophic calcification; present in ~30% but highly specific; the only CT finding distinguishing ABPA from CF bronchiectasis
(Fishman's Pulmonary Diseases and Disorders, pp. 2325-2326)
Diagnosis - ISHAM 2024 Revised Guidelines
(Agarwal R et al., Eur Respir J 2024, PMID: 38423624 - Revised ISHAM-ABPA Working Group Guidelines)
Mandatory prerequisite (must be present):
- Predisposing condition (asthma or CF) OR compatible clinico-radiological presentation
- Demonstration of A. fumigatus sensitisation - specific IgE ≥0.35 kUA/L
- Serum total IgE ≥500 IU/mL
Plus at least 2 of the following:
- Fungal-specific IgG elevated (precipitins to A. fumigatus)
- Peripheral blood eosinophilia ≥500 cells/µL
- Imaging consistent with ABPA: bronchiectasis, mucus plugging, or high-attenuation mucus on CT; OR fleeting opacities on CXR
Key update: The ISHAM 2024 guidelines removed the "mandatory" criterion of central bronchiectasis from diagnosis, making it possible to diagnose ABPA earlier (seropositive ABPA without bronchiectasis / ABPA-S) before irreversible structural damage occurs.
Screening recommendation: Screen all newly diagnosed asthmatic adults at tertiary care with A. fumigatus-specific IgE. In children, screen only those with difficult-to-treat asthma.
Classic diagnostic criteria (Fishman's, still useful for context):
(a) Asthma, (b) immediate cutaneous reactivity to Aspergillus antigens, (c) total IgE >1000 IU/mL, (d) elevated specific IgE and IgG to A. fumigatus, (e) central bronchiectasis.
Staging / Classification - ISHAM 2024
The prior numbered stages (I-V) have been abandoned to avoid the misconception of sequential progression. The updated classification uses 5 clinical categories:
| Category | Description |
|---|---|
| Acute ABPA | Newly diagnosed, active disease |
| Response | Improving on treatment (≥25% fall in IgE, resolution of symptoms/infiltrates) |
| Remission | Sustained response off treatment for ≥6 months |
| Treatment-dependent ABPA | Relapse on reducing/stopping therapy |
| Advanced ABPA | Established bronchiectasis, fibrosis, or persistent radiological changes |
Removed categories: Asymptomatic stage and glucocorticoid-dependent asthma (no clear treatment implications).
Management - ISHAM 2024
Acute ABPA (newly diagnosed or exacerbation)
First-line (either monotherapy):
- Oral prednisolone: 0.5 mg/kg/day for 2-4 weeks, tapered and completed over 4 months
- Oral itraconazole: (dose-adjusted per weight/renal function) as an alternative
Important recommendations:
- Combination of itraconazole + glucocorticoids is NOT recommended as first-line for acute ABPA
- A short course of glucocorticoids (<2 weeks) may be used as bridging along with itraconazole
- High-dose inhaled corticosteroids (ICS) should NOT be used as primary therapy for acute ABPA (consensus 100%)
- Biologics (omalizumab, dupilumab) should NOT be used as primary therapy for acute ABPA (consensus 97%)
- Asymptomatic ABPA patients should not routinely be treated
Recurrent ABPA Exacerbations
- Combination of prednisolone + itraconazole is recommended
Monitoring Treatment Response (8-12 weeks)
Using a multidimensional objective criterion:
- Clinical symptoms improvement
- Serum total IgE decrease (target ≥25% fall)
- Chest radiograph/CT improvement
Exacerbations post-treatment should be managed the same as newly diagnosed acute ABPA.
Role of Biologics (adjunctive)
- Omalizumab (anti-IgE): May reduce exacerbations in treatment-dependent ABPA; systematic reviews support its adjunctive role but NOT as monotherapy
- Dupilumab (anti-IL-4/13): Emerging evidence in ABPA complicating asthma
- Neither is recommended as primary treatment for acute ABPA
Allergic Bronchopulmonary Mycosis (ABPM) - New in ISHAM 2024
A new separate entity defined for patients with ABPA-like presentation but normal A. fumigatus-specific IgE. Diagnosis requires:
- Elevated fungus-specific IgE (non-fumigatus) ≥0.35 kUA/L
- Total IgE ≥500 IU/mL
- Two of: fungus-specific IgG; eosinophilia ≥500 cells/µL; repeated growth of causative fungus from sputum (mandatory for ABPM); suggestive imaging
Complications
- Irreversible central bronchiectasis and pulmonary fibrosis
- Chronic pulmonary aspergillosis (CPA) - develops in 10-20% of advanced ABPA
- Chronic respiratory failure
- Hemoptysis, pneumothorax (especially in CF)
Summary Points for Exam
| Feature | Key Point |
|---|---|
| Causative organism | Aspergillus fumigatus (>95%) |
| Predisposing conditions | Asthma (7-14%), CF (7-9%) |
| Immunology | Th2 hyperactivation, IgE-mediated (Type I) + immune complex (Type III) |
| Pathognomonic CT finding | High-attenuation mucus plugs |
| Hallmark CT finding | Central (proximal) bronchiectasis |
| Mandatory diagnostic criteria (ISHAM 2024) | Fungal sensitisation + IgE ≥500 IU/mL + 2 minor criteria |
| First-line treatment | Prednisolone 0.5 mg/kg/day x 4 months OR itraconazole monotherapy |
| NOT recommended as primary therapy | Combination steroids+azole (1st line), ICS alone, biologics as monotherapy |
| Treatment monitoring | Clinical + IgE + CXR at 8-12 weeks |
References:
- Fishman's Pulmonary Diseases and Disorders, 5th Ed., Chapter 132, pp. 2323-2327
- Agarwal R, Sehgal IS, Muthu V, et al. Revised ISHAM-ABPA working group clinical practice guidelines for diagnosing, classifying and treating allergic bronchopulmonary aspergillosis/mycoses. Eur Respir J 2024. PMID: 38423624
Note on "2026 ISHAM guidelines": The most current version is the 2024 revised ISHAM-ABPA guidelines published in the European Respiratory Journal (Agarwal et al., ERJ 2024, PMID 38423624). A comment/update was published in ERJ April 2026 (PMID: 41927072) but represents correspondence, not a new full guideline revision. The 2024 guidelines remain the current operative standard.
This is a shared conversation. Sign in to Orris to start your own chat.