To determine the prevalence of subdural hematoma (SDH) in patients presenting with primary nontraumatic lobar intracerebral hemorrhage (ICH) and characteristics associated with the presence of SDH.
Retrospective analysis of data collected in a prospective cohort study.
Consecutive sample of 200 patients with primary lobar ICH and 75 patients with deep hemispheric ICH.
Main Outcome Measures
Presence of SDH and mortality.
Subdural hematoma was present in 40 of 200 patients (20%) with primary lobar ICH. By contrast, SDH was not present in any of 75 consecutive patients with deep hemispheric ICH (P < .001 for comparison with lobar ICH). Intracerebral hemorrhage volume higher than 60 cm3 was the only independent predictor of SDH (odds ratio [OR], 2.69; 95% confidence interval [CI], 1.14-6.34; P = .02). Subdural hematoma thickness more than 5 mm was an independent predictor of increased 30-day mortality (OR, 7.60; 95% CI, 1.86-30.99; P = .005) after controlling for other factors including ICH volume. Further analysis showed that the effect of SDH on mortality depended on ICH volume, with larger odds for mortality in those with low ICH volume (OR, 12.85; 95% CI, 2.42-68.23; P = .003 for those with ICH volume <30 cm3). Cerebral amyloid angiopathy was present in 8 of 9 patients with pathological specimens.
Nontraumatic SDH frequently accompanies primary lobar ICH and is associated with higher 30-day mortality, particularly when the ICH volume is relatively low. Rupture of an amyloid-laden leptomeningeal vessel, with extravasation into the brain parenchyma and subdural space, may be the pathogenic mechanism.