Case Report: Synthetic cannabinoids as a cause for black carbonaceous bronchoalveolar lavage

Biswas,A., Patel, V., Jantz, M., Mehta, H.J. (2015) Synthetic cannabinoids as a cause for black carbonaceous bronchoalveolar lavage. BMJ Case Reports,  doi: 10.1136/bcr-2015-211391

A direct link to the PDF paper is here.

The authors are from the Department of Pulmonary, Critical Care and Sleep Medicine at the University of Florida (Gainesville, FL) and the Department of Pulmonary and Critical Care Medicine of Saint Joseph Heart and Lung Institute (Phoenix, AZ).

I am neither a pathologist nor a medical doctor of any kind, so I won’t go into detail about the pathology other than some general documented findings the authors observed.

This case is of a 44 year old woman  who is an ex-smoker (quit 10 years ago), but currently uses cocaine and cannabis. She has HIV and has had past mycobacterial and pneumocystis infections. The woman presented to hospital with subacute fever (5 day duration). She had a cough with productive yellow sputum, which eventually developed into a dry cough. Chest x-ray was suggestive of pneumonia. According to the authors the patient’s clinical, radiographic, and histopathology “was consistent with respiratory bronchiolitis-associated interstitial lung disease (RB-ILD). Bronchoalveolar lavage fluid was colored black.

Interestingly, in the "Learning Points" section, the authors state:

 

Pulmonary complications may result from impurities inhaled during the process of cocaine smoking. We propose that synthetic cannabinoids can do the same by a similar mechanism.

Other than the title of the paper, this is the only time “synthetic cannabinoids” are mentioned.

What am I missing here? How are synthetic cannabinoids involved in this case report? I’m confused.  The title of this case report is "Synthetic cannabinoids as a cause...". That leads one to believe that synthetic cannabinoids or use of associated products were involved in some fashion, but I’m not sure where they actually fit it other than a possible undiscussed hypothesis from the authors. Synthetic cannabinoids aren't even mentioned at at all in the patient's history, so why throw that hypothesis out there?!?