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  • Clinical courses and prognosis of spontaneous non-aneurysmal subarachnoid hemorrhage: a single institution experience

    Final Number:

    Ayako Yamazaki MD PhD; Yoshinori Sakata MD; Yujirou Obikane; Hidetsugu Maekawa MD; Michihiro Tanaka; Hiromu Hadeishi MD, PhD

    Study Design:
    Clinical Trial

    Subject Category:

    Meeting: Congress of Neurological Surgeons 2012 Annual Meeting

    Introduction: In spontaneous subarachnoid hemorrhage, patients without cerebral aneurysms detected on angiography (non-aneurysmal subarachnoid hemorrhage (NASAH)) account for 10-15%. These patients have been treated empirically and generally show a favorable prognosis. We retrospectively analyzed clinical course, complications and prognosis in NASAH patients.

    Methods: We collected information on 317 patients with spontaneous SAH admitted to our center between 2006 and 2011. Of these 317 patients, 23 (7.3%) were diagnosed with NASAH. All patients underwent cerebral angiography and/or 3-dimensional computed tomography (CT) angiography. Repeated cerebral angiography was usually performed about 2 weeks after first ictus, and confirmed the absence of both aneurysms and abnormal vessels. Based on the results of initial CT or magnetic resonance imaging, NASAH patients were classified as perimesencephalic, convexity or diffuse type. Clinical course, complications and Glasgow outcome scale (GOS) score were compared between these 3 subgroups.

    Results: Among the 23 NASAH patients, 21 were rated as grade I-II and 1 patient was classified as grade V on the Hunt & Kosnik scale (a sedated patient transferred from another hospital, initial symptoms were unclear) on admission. No mortality was seen among these patients, and 21 patients (91%) showed good outcomes. One patient with systematic sclerosis suffered convexity SAH twice (GOS score, 3). Another patient with diffuse SAH developed hydrocephalus (GOS score, 4). After discharge, 2 patients with convexity SAH developed intracerebral hemorrhage.

    Conclusions: Although the vast majority of patients with NASAH showed good prognosis, some non-negligible complications are occasionally encountered, such as hydrocephalus and intracerebral hemorrhage. Convexity SAH may include various types of pathology and etiology.

    Patient Care: To search risk factors of unfavorable prognosis may lead to the recognition of patients who require intentional treatments.

    Learning Objectives: By the conclusion of this session, participants should be able to: 1) describe the importance of classification of NASAH. 2) discuss the factor of unfavorable outcome. 3) identify an effective management to avoid both excess treatment and underestimation of the risk.


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