ABSTRACT
Subarachnoid hemorrhage, whether caused by the rupture of an aneurysm, arteriovenous malformation, or head trauma, can result in severe brain injury. Although much of this injury occurs with the initial event and is often fatal or irreversible, secondary factors also contribute significantly to morbidity and mortality. Attempts to improve outcome are generally designed to address these factors. Rehemorrhage is the most devastating complication following subarachnoid hemorrhage, and carries a high mortality. Additional brain injury can occur as a result of cerebral edema and intracranial hypertension. Cerebral ischemia resulting from vasospasm is another leading cause of delayed neurological deterioration. Hydrocephalus can result in either gradual or precipitous decline in neurological status. Some patients develop recurrent seizures. In addition, subarachnoid clots may have direct toxic effects on the brain. Recently, attention has focused on the role of free radicals, particularly the effects of membrane lipid peroxidation on the blood-brain barrier (BBB), cerebral edema, and vasospasm. Focus on the secondary causes of brain injury has led to the development of newer surgical, endovascular, and phamacological treatments in subarachnoid hemorrhage. Nevertheless, subarachnoid hemorrhage continues to be a significant cause of death and disability.
