Update from CDC on vape-related lung injury: No single cause yet

The CDC has posted a MMWR report on the 2019 spate of serious lung injuries reported as a consequence of vaping. The first culprit to hit the news was vitamin E, it turns out this is not a unique factor after all.

Schier and colleagues report: No consistent e-cigarette product, substance, or additive has been identified in all cases, nor has any one product or substance been conclusively linked to pulmonary disease in patients. … authors identified lipids within alveolar macrophages from the three bronchoalveolar lavage (BAL) specimens stained with oil red O. All five patients reported using marijuana oils or concentrates in e-cigarettes, and three also reported using nicotine (3). In a report describing the clinical course and outcomes of six patients from Utah, health care providers described the potential diagnostic utility of identification of lipid-laden macrophages from BAL specimens (4). Among the 53 cases from Illinois and Wisconsin, however, the pathologic findings were heterogeneous. Whereas almost half (24/53) of these patients underwent BAL, seven reports described the use of oil red O stain that identified lipid-laden macrophages

Perrine and colleagues report: Among 514 patients with information on substances used in e-cigarettes, or vaping products, in the 3 months* preceding symptom onset, 76.9% reported using THC-containing products, and 56.8% reported using nicotine-containing products; 36.0% reported exclusive use of THC-containing products, and 16.0% reported exclusive use of nicotine-containing products. *erratum for the original which says “30 days”.

It’s frustrating that the takeaway message so far is that nobody knows if there even is a unique cause or set of causes for the recent spate of lung injuries. We certainly don’t know the cause. We probably don’t even know if the injuries *are* recently occurring or have always been a consequence of vape device use that simply wasn’t connected to the e-cigarette device use. We know how long it took to recognize that cannabis was causing a hyperemesis syndrome, after all.

My suspicion at the start was that it wasn’t anything to do with cannabinoids, specifically. This reported diversity would appear to confirm that. It always seemed more likely to me that if there was a unique cause that appeared to be associated with cannabis vape cartridges that this is a classic case of a third variable. Perhaps a new vehicle constituent or an extraction method that was being used only, or primarily, with cannabis vape preparation. Well, clearly even that is not the case since there seem to be some nicotine-only users who have experienced lung injury.

Keep your eye on PubMed for updates on this health crisis.

Schier JG, Meiman JG, Layden J, et al. Severe Pulmonary Disease Associated with Electronic-Cigarette–Product Use — Interim Guidance. MMWR Morb Mortal Wkly Rep 2019;68:787–790. DOI: http://dx.doi.org/10.15585/mmwr.mm6836e2external icon

Perrine CG, Pickens CM, Boehmer TK, et al. Characteristics of a Multistate Outbreak of Lung Injury Associated with E-cigarette Use, or Vaping — United States, 2019. MMWR Morb Mortal Wkly Rep 2019;68:860–864. DOI: http://dx.doi.org/10.15585/mmwr.mm6839e1

Erratum: Vol. 68, No. 39. MMWR Morb Mortal Wkly Rep 2019;68:900. DOI: http://dx.doi.org/10.15585/mmwr.mm6840a5