Convexal subarachnoid hemorrhage in ischemic stroke

Case contributed by Karina Dorfman


Admitted with dysarthria and mouth deviation for the last 12 hours.

Patient Data

Age: 70 years
Gender: Male

Brain CT at admission


A large area of hypoattenuation with loss of gray-white matter differentiation involving the left parietal and insular cortex, corresponds to acute ischemic stroke. CTA shows complete occlusion of the left ICA.

Follow up brain CT after 4 days of treatment with dual anti-platelet treatment


Prominent hypodensity involving the left parietal and insular cortex corresponds to early subacute ischemic stroke.

New subarachnoid hemorrhage in left parietal convexity, separate from the stroke area.

The patient was clinically stable. On follow-up CT on the next day, the findings were stable and the patient was discharged after several days with a recommendation to perform a follow-up CT in the next two weeks.

Follow up CT, 10 days after the initial clinical presentation


The left parietal area of stroke is much less prominent compared to previous examinations, as a result of the fogging phenomenon. In a post-contrast study, gyral enhancement is shown in the stroke area. These findings are typical for the subacute phase of ischemic stroke.

The left parietal subarachnoid hemorrhage resolved.

Case Discussion

Convexal subarachnoid hemorrhage occurs within the surface sulci of the brain, without involving the basal cisterns or ventricles.
Internal carotid artery occlusion is one of the rare causes of convexal subarachnoid hemorrhage. The proposed mechanism is the fragility of collateral pial vessels with subsequent rupture. The antiplatelet therapy, as well as a possible reperfusion injury, may contribute to the development of convexal subarachnoid hemorrhage in the setting of ischemic stroke in patients with occlusive disease of the internal carotid artery.

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