Definition Bronchospasm: Cause Bronchospasm is is a reversible reflex spasm of the smooth muscle in the bronchi. Bronchospasm is vagally mediated and caused by histamine, or one of many noxious stimuli, including cold air, inhaled irritants, and instrumentation (eg, tracheal intubation). Bronchospasm is mediated by vagal afferents which result in an increase in cyclic guanosine […]