Classification of Non-Aneurysmal Subarachnoid Haemorrhage: CT Correlation to the Clinical Outcome

Abstract

To propose a new computed tomography (CT)-based classification system for nonaneurysmal subarachnoid haemorrhage (SAH), which predicts patients' discharge clinical outcome and helps to prioritize appropriate patient management. A 5-year, retrospective, two-centre study was carried out involving 1486 patients presenting with SAH. One hundred and ninety patients with nonaneurysmal SAH were included in the study. Initial cranial CT findings at admission were correlated with the patients' discharge outcomes measured using the Modified Rankin Scale (MRS). A CT-based classification system (type 1 e 4) was devised based on the topography of the initial haemorrhage pattern. Seventy-five percent of the patients had type 1 haemorrhage and all these patients had a good clinical outcome with a discharge MRS of 1. Eight percent of the patients presented with type 2 haemorrhage, 62% of which were discharged with MRS of 1 and 12% of patients had MRS 3 or 4. Type 3 haemorrhage was found in 10%, of which 16% had good clinical outcome, but 53% had moderate to severe disability (MRS 3 and 4) and 5% were discharged with severe disability (MRS 5). Six percent of patients presented with type 4 haemorrhage of which 42% of the patients had moderate to severe disability (MRS 3 and 4), 42% had severe disability and one-sixth of the patients died. Highly significant differences were found between type 1 (1a and 1b) and type 2 (p¼ 0.003); type 2 and type 3 (p ¼ 0.002); type 3 and type 4 (p ¼ 0.001). Haemorrhages of the type 1 category are usually benign and do not warrant an extensive battery of clinical and radiological investigations. Type 2 haemorrhages have a varying prognosis and need to be investigated and managed along similar lines as that of an aneurysmal haemorrhage with emphasis towards radiological investigation. Type 3 and type 4 haemorrhages need to be extensively investigated to find an underlying cause.