Background and purpose: Extension of hemorrhage into the subarachnoid space is observed in primary intracerebral hemorrhage (ICH), yet the phenomenon has undergone limited study and is of unknown significance. The objective of this study is to evaluate the incidence, characteristics, and clinical consequences of subarachnoid hemorrhage extension (SAHE) in ICH on functional outcomes.
Methods: Patients with primary ICH were enrolled into a prospective registry between December 2006 and June 2012. Patients were managed and serial neuroimaging was obtained per a structured protocol. Presence of any subarachnoid blood on imaging was identified as SAHE by expert reviewers blinded to outcomes. Regression models were developed to test whether the occurrence of SAHE was an independent predictor of functional outcomes as measured with the modified Rankin Scale.
Results: Of 234 patients with ICH, 93 (39.7%) had SAHE. Interrater agreement for SAHE was excellent (kappa=0.991). SAHE was associated with lobar hemorrhage location (65% of SAHE vs 19% of non-SAHE cases; P<0.001) and larger hematoma volumes (median 23.8 vs 6.7; P<0.001). Fever (69.9% vs 51.1%; P=0.005) and seizures (8.6% vs 2.8%; P=0.07) were more common in patients with SAHE. SAHE was a predictor of death by day 14 (odds ratio, 4.45; 95% confidence interval, 1.88-10.53; P=0.001) and of higher (worse) modified Rankin Scale scores at 28 days (odds ratio, 1.76 per mRS point; 95% confidence interval, 1.01-3.05; P=0.012) after adjustment for ICH score.
Conclusions: SAHE is associated with worse modified Rankin Scale independent of traditional ICH severity measures. Underlying mechanisms and potential treatments of SAHE require further study.