Clinical Presentation, Etiology, and Long-Term Prognosis in Patients With Nontraumatic Convexal Subarachnoid Hemorrhage

Background and Purpose-Nontraumatic subarachnoid hemorrhage at the convexity of the brain (cSAH) is an incompletely characterized subtype of nonaneurysmal subarachnoid bleeding. This study sought to systematically describe the clinical presentation, etiology, and long-term outcome in patients with cSAH. Methods-For a 6-year period, we searched our radiological database for patients with nontraumatic nonaneurysmal subarachnoid hemorrhages (n = 131) seen on CT or MRI. By subsequent image review, we identified 24 patients with cSAH defined by intrasulcal bleeding restricted to the hemispheric convexities. We reviewed their medical records, analyzed the neuroimaging studies, and followed up patients by telephone or a clinical visit. Results-The 24 patients with cSAH had a mean age of 70 years (range, 37-88 years), 20 (83%) were >60 years, and 13 (54%) were women. Patients often presented with transient sensory and/or motor symptoms (n = 10 [42%]) and seizures (n = 5 [21%]), whereas headaches typical of subarachnoid hemorrhage were rare (n = 4 [17%]). MRI provided evidence for prior bleedings in 11 patients (microbleeds in 10 and parenchymal bleeds in 5) with a bleeding pattern suggestive of cerebral amyloid angiopathy in 5 subjects. At follow-up (after a mean of 33 months), 14 patients (64%) had an unfavorable outcome (modified Rankin scale score 3-6), including 5 deaths. We did not observe recurrent cSAH. Conclusions-Our data suggest that cSAH often presents with features not typical for subarachnoid bleeding. In the elderly, cSAH is frequently associated with bleeding-prone conditions such as cerebral amyloid angiopathy. Recurrence of cSAH is rare but the condition itself is a marker of poor prognosis. (Stroke. 2011; 42:3055-3060.)