Convexal subarachnoid hemorrhages (cSAH), also known as convexity subarachnoid hemorrhage, are subarachnoid hemorrhages that occur within the cortical sulci of the brain.
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Epidemiology
Convexal subarachnoid hemorrhage accounts for approximately 6% of all subarachnoid hemorrhage 7.
Pathology
There are various causes of convexal subarachnoid hemorrhage, including 1-6:
trauma or post-operative changes
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vascular malformations
severe internal carotid artery stenosis or intracranial atherosclerotic disease
primary brain tumors
Radiographic features
Imaging reveals abnormalities localized to the cortical sulci. This is a markedly different pattern to other forms of subarachnoid hemorrhage, e.g. the basal cisternal distribution of aneurysmal subarachnoid hemorrhage.
CT
CT brain findings may be subtle, demonstrating curvilinear hyperdensities localized to one or more adjacent cortical sulci 5.
CT angiogram or venogram may be useful to perform as work-up for the underlying cause 6.
MRI
MRI brain demonstrates hyperintensity in the subarachnoid space on FLAIR localized to one or more adjacent cortical sulci, as well as hypointense blooming artifact on GRE/SWI 5.
Treatment and prognosis
Management depends on the underlying cause 6, with most cases being managed conservatively.