Spontaneous Pneumothorax Secondary to Bullous Lung Emphysema Positive for Cannabinoids upon Toxicological Examination.

Cannabis can be related to respiratory diseases, but the relationship between smoking marijuana and the development of a pneumothorax has scarcely been investigated. We aimed to analyze, in patients with a history of cannabis smoking abuse submitted to lung apicectomy for a primary spontaneous pneumothorax (PSP), the correlation between the presence of cannabinoids in the resected lung and the detection of bullous emphysema within the same tissue. Patients undergoing lung apicectomy for a PSP were prospectively enrolled, and the correlation between the presence of cannabinoids in the resected lung tissue and histological finding of bullous emphysema was investigated with Fisher's exact test. There were 21 male patients, with a median age of 27 years. The cannabinoids found by the toxicological examination in surgical specimens were mainly delta-9-tetrahydrocannabinol (THC), cannabinol (CBN), and cannabidiol (CBD). In 14/21 patients, cannabinoids were detected in the resected lung tissue, and bullous emphysema was present in 13/14 of these (93%), while bullous emphysema was found in only 1/7 (14%) of the remaining patients who were negative for cannabinoids in the lung tissue, and the difference was found to be statistically significant ( < 0.0009). Our study demonstrated the presence of bullous emphysema in most cannabinoid-positive patients and its absence in most of those who were cannabinoid-negative, supporting the correlation between cannabinoids in the lung tissue and bullous emphysema with the development of a "secondary" spontaneous pneumothorax.