Fact-sheet: Subarachnoid hemorrhage
  • Subarachnoid hemorrhage


Updated on 10/26/2017 at 12:34 PM

Note : 0/10
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Definition

Hemorrhage in the subarachnoid space (between the arachnoid and the pia mater) Etiologies: - Aneurysm rupture (85%) - Idiopathic (10%) - Other (5%): Vascular: AVM, dural fistula, cavernoma, cerebral venous thrombosis, amyloid angiopathy, Reversible cerebral vasoconstriction syndrome, intracranial dissection, Moyamoya disease, vasculitis, mycotic aneurysms (rather distal), Tumoral: pituitary apoplexy, schwannoma, meningioma, hemangioblastoma, glioma.

Clinical features

Sudden "thunderclap" headache - Hyperacute onset - VAS >8/10 from onset

Laboratory findings

LP in the absence of contraindications, if and only if CT scan is normal: uniformly red, non-clotting fluid in all three tubes.
Xanthochromic supernatant after centrifugation.
Erythrocyte/leukocyte ratio higher than that of blood.
Elevated CSF pressure.

CT

Confirms the diagnosis: spontaneous hyperdensity of the cortical sulci, sylvian fissures, and basal cisterns.
Guides the location of the ruptured aneurysm based on the predominant location of the hemorrhage.
Screening for complications (early/during follow-up): hematoma, intraventricular hemorrhage, acute hydrocephalus.

MRI

T2/FLAIR hyperintensity of the subarachnoid spaces.
Caution: flow artifacts on axial T2 can often mimic subarachnoid hemorrhage in the basal cisterns
-> artifacts reduced on 3D FLAIR.

Vascular intervention

Confirmation of the presence of the ruptured aneurysm (only definitive criterion: contrast extravasation) and aneurysm exclusion (coiling).
Diagnosis of other aneurysms.
Diagnosis of vasospasm during follow-up.

Management

Symptomatic treatment.
Prevention of secondary brain insults.
Vasospasm prevention.
External ventricular drainage if acute hydrocephalus.
Semi-urgent cerebral X-Ray Angiography.

Classification

FISHER
Grade I: no blood (positive LP).
Grade II: thin layer of blood < 1 mm thick.
Grade III: layer of blood > 1 mm.
Grade IV: intraparenchymal hematoma or intraventricular hemorrhage.
Vasospasm risk >20% if Fisher III.
Modified FISHER:
Grade 0: no blood in cisterns or ventricles.
Grade 1: minimal subarachnoid hemorrhage, no intraventricular hemorrhage in both lateral ventricles.
Grade 2: minimal subarachnoid hemorrhage, intraventricular hemorrhage in both lateral ventricles.
Grade 3: extensive subarachnoid hemorrhage, no intraventricular hemorrhage in both lateral ventricles.
Grade 4: extensive subarachnoid hemorrhage, intraventricular hemorrhage in both lateral ventricles.

Differential diagnosis

FLAIR hyperintensities of the convexity sulci:
-Oxygen therapy
-Meningitis
-Leptomeningeal carcinomatosis