Drugs implicated: marijuana, cocaine, methamphetamine, heroin, opiates, Ecstasy
Mechanism: Valsalva maneuver. This may occur while smoking a drug of abuse in an attempt to retain as much drug as possible. It can also occur during extreme exertion.
Clinical features:
(1) The patient either smokes a drug of abuse or undergoes extreme physical exertion.
(2) The patient develops thoracic symptoms with or without subcutaneous emphysema.
(3) The pneumomediastinum and soft tissue emphysema may be subclinical unless an MRI or CT scan is performed.
(4) Exclusion of other explanations (trauma, gunshot, etc).
The diagnosis often depends on knowledge that a drug has been abused. Drug users often deny use until confronted with irrefutable evidence. If the person presents within 48 hours of exposure then urine drug testing may be positive. Hair testing can be used to detect long-term exposure but may be negative for any exposure within the past few days (until newly formed hair emerges).
