Subarachnoid hemorrhage

Introduction
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By Tania Rebeiz MD and James R Brorson MD

Subarachnoid hemorrhage is also known as or subsumes Meningeal hemorrhage. -ed.

The authors review the epidemiology, pathophysiology, diagnostic evaluation, and treatment of spontaneous subarachnoid hemorrhage and its secondary complications, including aneurysm rebleeding, hydrocephalus, hyponatremia, seizures, delayed cerebral ischemia, and cardiopulmonary problems. Newer hypotheses on the mechanism of delayed cerebral ischemia following subarachnoid hemorrhage are explained. Recommendations from the 2011 Neurocritical Care Society Guidelines and the 2012 American Heart Association/American Stroke Association guidelines for the management of aneurysmal subarachnoid hemorrhage are included.

Key points

  • Subarachnoid hemorrhage constitutes a life-threatening neurologic emergency and typically presents with a sudden severe headache, most often occurring from ruptured intracranial aneurysm.
  • The most common diagnostic error accounting for missed diagnosis of subarachnoid hemorrhage is failure to obtain a noncontrast head CT.
  • The most important predictive factors for acute prognosis after subarachnoid hemorrhage include level of consciousness, neurologic grade on admission, patient age, and amount of blood on initial scan.
  • Subarachnoid hemorrhage can be complicated by fatal rebleeding, arterial vasospasm, cerebral ischemia, seizures, metabolic derangements, and venous thrombosis.
  • Surgical clipping or endovascular coiling of the underlying ruptured aneurysm should be performed as soon as possible to limit the chance of aneurysm rebleeding.
  • Delayed cerebral ischemia following subarachnoid hemorrhage has been considered to be a direct consequence of vasospasm; however, an emerging body of literature suggests a multifactorial etiology beyond pure cerebral arterial constriction.

In This Article

Introduction
Historical note and nomenclature
Clinical manifestations
Clinical vignette
Etiology
Pathogenesis and pathophysiology
Epidemiology
Prevention
Differential diagnosis
Diagnostic workup
Prognosis
Management
Outcomes
Pregnancy
Anesthesia
References cited
Contributors