Does cannabis smoking predispose to lung bulla formation?

OBJECTIVE: The data of a consecutive series of habitual marijuana smokers were retrospectively evaluated and compared with that of non-marijuana smokers to assess differences between the 2 groups. METHODS: 13 consecutive habitual marijuana smokers were referred for treatment of spontaneous pneumothorax. The demographic, clinical, radiological, and pathological findings of these patients were reviewed and compared with 140 non-marijuana smokers treated for the same pathology at the same time. RESULTS: Bullae were seen in 8/13 (62%) and 110/140 (78%) of marijuana smokers and non-marijuana smokers, respectively. However, when patients less than 35-years old were considered, the incidence of bulla was higher in marijuana smokers than non-marijuana smokers (7/10 vs. 3/10, p < 0.05). The pathological findings showed a greater presence of inflammatory cells in specimens from marijuana smokers than those of non-marijuana smokers (8/11 vs. 2/42, respectively, p < 0.05). No significant differences in hospital stay and clinical outcome were registered between the 2 groups. CONCLUSIONS: Despite the fact that we were unable to demonstrate that marijuana had a causal role in the development of emphysema, our study showed that marijuana smokers had a higher incidence of inflammatory cells in pathological specimens, which may favor lung injury, thus predisposing to bulla formation.