Allergic Bronchopulmonary Aspergillosis (ABPA)

Question 1

What is the criteria to diagnose ABPA?

Answer 1

2013 ISHAM criteria:
A) Predisposing condition (need to have 1):
Asthma
Cystic fibrosis

B) Obligatory (both need to be present):
Total IgE>1000IU/ml
+ve A.fumigaturs specific IgE (>0.35kUA/L), or skin prick test

C) 2/3 other criteria:
Raised A.fumigatus specific IgG, or precipitins
Eos >500cells/uL
Radiological changes consistent with ABPA

Question 2

What is the Rx for ABPA?

Answer 2

1) Oral corticosteroid & T. Itraconazole

Regimen:
Prednisolone
0.5mg/kg/day for 2w,
then 0.5mg/kg/day EOD for 6-8w,
then taper 5-10mg every 2w

Itraconazole
200mg BD for 4-6m with TDM level (aim 1-1.5mcg/ml - efficacy. <5-6mcg/ml to minimize toxicity)
- used in steroid-dependent and relapse, following steroids
- help reduce IgE level, decrease Sx & decrease steroid requirements
other azoles that can be used: voriconazole, posaconazole

Omalizumab (anti IgE antibody): use as 2nd or 3rd line if steori or itraconazole are not controlling the disease

2) Monitoring of disease:
- IgE level every 6-8w for 1 year –> aim to reduce IgE 35-50%
- CXR 4-8w of oral corticosteroid to Ax resolution

Question 3

Other types of aspergillus infection apart from ABPA

Answer 3

1) Aspergilloma
= fungal ball/ mycetoma
- usually develops in pre-existing lung cavity caused by TB/ sarcoidosis/ CF, emphysematous bullae, necrotizing infection
- Sx: can be asymptomatic, haemoptysis
- Ix: radiological imaging (intracavitary mass), serum A.fumigatus specific IgG
- Rx:
in ASx & single mycetoma which is not progressing over 6-24m: observe
with haemoptysis: Resection. Peri/post-operative anti-fungal not usually required unless concern re spillage of aspergilloma

2) Chronic necrotizing aspergillosis
= subacute local invasion of lung tissue. Pre-existing cavity is not required
- Sx: >1 month of LOW, fever, malaise, fatigue, chronic productive cough, haemoptysis
- Risk: immunocompromised
- Ix:
CT scan (halo sign, crescent sign, nodule, GGO, pulmonary infarct, consolidation
Inflam markers, serum precipitins
skin test aspergillus antigen
Lung Bx
BAL Aspergillus PCR
- Rx: iv voriconazole (6mg/kg) BD for 1d, the 4mg/kg BD , then can oralise 200-300mg BD for 6-12w
- SE (s) of voriconazole: visual disturbance, hepatotoxicity, rash, N/V/D, QT prolong, arrhythmia, hallucination

3) Invasive aspergillosis
= invasion of lung tissue on HPE
- Sx: rapid often fatal, fever, cough, pleuritic chest pain, haemoptysis
- Risk factors:
a) prolonged neutropenia (<500 cells/mm3 for >10d)
b) transplant (esp lung & bone marrow)
c) prolonged steroid use (>3w)
d) chemo
e) AIDS
f) chronic granulomatous disease
- Rx: similar to chronic necrotizing aspergillosis

Question 4

What are the stages of ABPA? (5)

Answer 4

0: ASx (but fulfil ISHAM criteria)
1: Active ABPA (symptomatic asthma & fulfils ISHAM)
2: In remission (
3: Recurrent ABPA (worsening clinical & radiological findings, increase IgE ≥50% from remission level)
4: Chronic, steroid-dependent (systemic steroid is used to control asthma & ABPA Sx)
5: Fibro-cavitary & airway dilatation (complications occur e.g. T2RF, cor pulmonale)

Question 5

Radiological changes suggestive of ABPA

Answer 5

On CXR:
Parallel-line shadow
RIng shadow
Pulmonary fibrosis with cavitation
Consolidation
Mucoid impaction: finger in glove opacity

On CT:
Centrilobular nodule
Central bronchiectasis

In Aspergilloma: intracavitary mass
In Invasive aspergilloma: Halo sign

Question 6

Other conditions assoc with allergy to other fungus (2)

Answer 6

1) Severe asthma with fungal sensatization
- predisposing factor: asthma
- features: IgE <1000, IgE A.fumigatus -ve, allergic to other fungus +ve, HRCT normal

2) Allergic bronchopulmonary mycosis (ABPM)
- predisposing factor: asthma
- features: IgE >1000, IgE A.fumigatus -ve, allergic to other fungus +ve, HRCT bronchiectasis