On Monday, second year fellow Tom Bolig presented the course of a middle aged undomiciled man with heroin use disorder and recurrent severe asthma exacerbations. This patient had no history of peripheral eosinophilia or IgE elevation. He was non-adherent to maintenance inhaler therapy. He was admitted to the MICU after intubation for asthma exacerbation following unintentional heroin overdose.
This prompted a discussion of the entity of potentially fatal asthma (PFA), defined by Northwestern’s own Paul Greenberger (1,2)
Potentially fatal asthma (PFA) is a clinical condition wherein 1+ of the following are present:
- History of endotracheal intubation
- Acute respiratory acidosis or respiratory failure from asthma
- 2+ episodes of pneumothorax or pneumomediastinum from asthma
- 2+ episodes of acute severe asthma despite long-term use of oral steroids (pre-biologic era) or other asthma medications
Why is this so important?
- Condition with high risk for mortality and a young (mean 40 ya) patient population!
- Identification may be the first step to tailored management
- Loss to follow-up more commonly observed in patients who died of disease
- Comorbid psychiatric illnesses and social barriers to health commonly observed
Back to Tom’s patient – a NBBAL was performed with PMN predominance, non-pathologic growth on cx, strongly positive amylase and a galactomannan Ag of 3.87. CT imaging showed patchy bibasilar infiltrates, not consistent with invasive pulmonary aspergillosis (IPA).
What are the most recent recommendations on interpretation of testing in suspected IPA?
All of the following from 2019 ATS Guidelines (3) with strong recommendation/high quality evidence
- If hematologic malignancy/solid organ transplant with suspected IPA, obtain serum galactomannan
- If serum galactomannan negative in above but high suspicion remains, obtain BAL galactomannan
- If serum galactommannan positive but risk factors for false positive (active chemotherapy, suspected/confirmed mucositis), obtain BAL galactomannan
- If severe immune compromise as above and suspected IPA, add serum aspergillus PCR to testing above
Tom’s patient fell outside the best studied population (hematologic malignancy and transplant) for galactomannan testing for IPA, and suspicion for disease based off of CT evidence was low. Although this has not been described in the literature, Ben Singer raised the possibility of aspiration of fungal cell wall contents from oropharynx as a putative cause of transiently elevated BAL galactomannan.
Finally, Tom discussed “Mab” therapy for asthma, providing a quick reference chart that takes some of the guesswork out of determining indications:
Thanks, Tom!
Sources:
- Allergy and Asthma Proceedings (1988); 9(2):147-152.
- Chest (1992);101:401S-402S.
- AJRCCM (2019);200:1326