Pneumorachis and pneumomediastinum caused by repeated Muller's maneuvers: Complications of marijuana smoking

Pneumomediastinum may occur during marijuana inhalation but only rarely has pneumorachis (epidural pneumatosis or aerorachia) been reported. The usual mechanisms that produce pneumomediastinum include severe acute asthma, tox ic-induced bronchial hyperreactivity, and barotrauma caused by Valsalva's m aneuver (expiration through resistance). We report a case in which barotrau ma resulted from repeated deep inspiration through a device with airflow re sistance equivalent to Muller's maneuver. Inspiration occurred through a ho memade apparatus resembling a narrow outlet bong with 2 piled compartments. Pneumomediastinum combined with subcutaneous emphysema and pneumorachis oc curred, without identified pneumothorax. There were no neurologic complicat ions. Because of the absence of bronchospasm, expiration either through the apparatus or actively against a closed glottis, or apnea, this phenomenon is likely a result of repeated Muller's maneuvers. Successive inhalation th rough resistance could have resulted in extreme negative intrathoracic pres sure, which would have caused a transmural pressure gradient inducing barot rauma and release of extra respiratory air. High-concentration oxygen thera py to achieve nitrogen washout was used.