Characteristics of losing consciousness at the onset of SAH included a history of hypertension, a discrete sentinel headache less than 2 weeks before the index bleeding event, persistent change in mental status, acute tonic-clonic activity, and cardiac arrest with successful cardiopulmonary resuscitation, among others.

The researchers found that in a univariate analysis, loss of consciousness was associated with an increased risk of all-cause neurologic deterioration, delayed cerebral ischemia (DCI), aneurysm rebleeding, and new infarction from any cause detected on follow-up CT scan. After adjusting for age, admission Hunt and Hess grade, APACHE II physiological subscore, and aneurysm size, LOC was associated with global cerebral edema but not with DCI or rebleeding.

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Of the 590 patients with LOC, 154 (51.2%) were dead or severely disabled at 12 months compared with 302 (17.7%) of those who did not lose consciousness. Even after adjusting for age, admission clinical grade, APACHE II physiological subscore, and aneurysm size, death or functional dependence at 1 year was significantly associated with LOC.

“In the future, the presence or absence of LOC may be useful for risk stratification and targeting therapy designed to minimize the effects of early brain injury after SAH,” the authors wrote.


  1. Suwatcharangkoon S, Meyers E, Falo C, et al. Loss of Consciousness at Onset of Subarachnoid Hemorrhage as an Important Marker of Early Brain Injury. JAMA Neurol. 2015; doi:10.1001/jamaneurol.2015.3188.