Bleeding in the space between the brain and subarachnoid layer that protects it.
It is caused by a blood vessel bursting due to a head injury or other factors that may lead to bleeding.
It manifests as a very intense headache of sudden appearance. It may be accompanied by other symptoms, including decreased level of consciousness, vomiting and a stiff neck.
Diagnosis is performed by clinical questioning, physical examination, cerebrospinal fluid tests obtained by lumbar puncture and a CT-scan.
Bleeding should be stopped by endovascular techniques and/or surgery. Vasodilator drugs are also used to prevent spasm in the affected blood vessels.
It is a life-threatening emergency that requires immediate medical attention. The associated mortality rate is 50% of all cases.
- J. Claude Hemphill III, Wade S. Smith, Daryl R. Gress. Cuidados intensivos neurológicos, incluídas encefalopatía hipóxica-isquémica y hemorragia subaracnoidea. Farreras Rozman. Medicina Interna. Volumen II. Duodécima edición. 1784:1787.
- Robert J Singer, Christopher S Ogilvy, Guy Rordorf. Clinical manifestations and diagnosis of aneurysmal subarachnoid haemorrhage. UpToDate. Sep 26, 2013.
- Suarez JI, Tarr RW, Selman WR. Aneurysmal subarachnoid hemorrhage. N Engl J Med 2006; 354:387.
- Edlow JA, Caplan LR. Avoiding pitfalls in the diagnosis of subarachnoid hemorrhage. N Engl J Med 2000; 342:29.

