Atraumatic convexal subarachnoid hemorrhage: Clinical presentation, imaging patterns, and etiologies

Abstract

OBJECTIVE: To identify patterns of clinical presentation, imaging findings, and etiologies in a cohort of hospitalized patients with localized nontraumatic convexal subarachnoid hemorrhage. METHODS: Twenty-nine consecutive patients with atraumatic convexal subarachnoid hemorrhage were identified using International Classification of Diseases-9 code from 460 patients with subarachnoid hemorrhage evaluated at our institution over a course of 5 years. Retrospective review of patient medical records, neuroimaging studies, and follow-up data was performed. RESULTS: There were 16 women and 13 men between the ages of 29 and 87 years. Two common patterns of presentations were observed. The most frequent presenting symptom in patients < or =60 years (n = 16) was a severe headache (n = 12; 75%) of abrupt onset (n = 9; 56%) with arterial narrowing on conventional angiograms in 4 patients; 10 (p = 0.003) were presumptively diagnosed with a primary vasoconstriction syndrome. Patients >60 years (n = 13) usually had temporary sensory or motor symptoms (n = 7; 54%); brain MRI scans in these patients showed evidence of leukoaraiosis and/or hemispheric microbleeds and superficial siderosis (n = 9; 69%), compatible with amyloid angiopathy (n = 10; p < 0.0001). In a small group of patients, the presentation was more varied and included lethargy, fever, and confusion. Four patients older than 60 years had recurrent intracerebral hemorrhages in the follow-up period with 2 fatalities. CONCLUSION: Convexal subarachnoid hemorrhage is an important subtype of nonaneurysmal subarachnoid bleeding with diverse etiologies, though a reversible vasoconstriction syndrome appears to be a common cause in patients 60 years or younger whereas amyloid angiopathy is frequent in patients over 60. These observations require confirmation in future studies.