Idiopathic subarachnoid hemorrhage

In approximately 15 % of cases, nor aneurysm or other vascular malformation can be identified by cerebral angiography as origin of the hemorrhage, and these are commonly defined as idiopathic subarachnoid hemorrhage SAH (ISAH). Because of the negative angiography, limited extension of the bleeding with prevalent prepontine pattern and the benign prognosis, the venous causes has been preferred rather than the arterial ones.

In the past, several possible explanations for idiopathic subarachnoid hemorrhage (ISAH) have been proposed; however, neuroimaging studies have never provided conclusive data about the structural cause of the bleeding 1).

Idiopathic subarachnoid hemorrhage is not clearly understood, and reasons suggested include the repair of a microaneurysm, the presence of vasospasm that prevents the aneurysm from filling up, the dissection of the basilary artery or other arteries, or bleeding from the perimesencephalic or other deep veins 2).

Alén JF, Lagares A, Campollo J, Ballenilla F, Kaen A, Núñez AP, Lobato RD. Idiopathic subarachnoid hemorrhage and venous drainage: are they related? Neurosurgery. 2008 Dec;63(6):1106-11; discussion 1111-2. doi: 10.1227/01.NEU.0000335777.14055.71. PubMed PMID: 19057322.
Boswell S, Thorell W, Gogela S, et al. Angiogramnegative subarachnoid hemorrhage: outcomes data and review of the literature. J Stroke Cerebrovasc Dis. 2013;22(6):750–757.
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  • Last modified: 2018/11/15 21:51
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