While respiratory adverse events have been reported previously with inhaled marijuana use, these were often connected with the additives. The authors report that this case is unique in that the hemoptysis was likely due to the marijuana as no other causes could be found. Pulmonary side effects of marijuana smoking are similar to that of tobacco which include cough, expectoration, inflammation of the respiratory tract, as well as bronchial cell growth changes which could lead to chronic bronchitis and cancer. One previous report also mentions fatal alveolar hemorrhage as a side effect in a patient who regularly smoked marijuana.
Hemoptysis is a symptom which may present in the setting of negative pressure pulmonary edema, where a large, negative intrathoracic pressure generated against an obstructed upper airway results in the shift of fluid into the interstitium of the lungs. Alveolar hemorrhage can occur when mechanical damage to the alveolar epithelial lining is present. In this patient, a transbronchial biopsy provided evidence of chronic inflammation supporting the conclusion that injury at the level of the distal bronchioles and/or alveoli was due to the chronic effects of marijuana on the lung parenchyma.
Because the drug is used often for recreational purposes, it is important that clinicians become aware and educate their patients about the potentially dangerous side effects of inhaling marijuana. Life-threatening complications may include respiratory failure, pulmonary edema secondary to hypertensive crises, myocardial infarction, and also hemoptysis. The authors conclude that “future reports on this phenomenon will hopefully give greater insight into this rare association to better define the pathophysiological mechanism linking hemoptysis with inhalational marijuana use.”
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