Risk factors and outcome of seizures after chronic subdural hematoma

Background: Seizures are important neurologic complications of chronic subdural hematoma (CSDH). A better understanding of risk factors of seizures following CSDH is needed to identify the patient who will require treatment. Methods: This one-year retrospective study enrolled 100 adult CSDH patients. Baseline prognostic variables were analyzed by Cox's proportional hazards model after a minimum of 18 months of follow-up. Results: Seizures occurred in 11 CSDH patients, including acute symptomatic seizures in 6.0% (6/100) and unprovoked seizures in 5.0% (5/100). None progressed to status epilepticus during hospitalization. After a minimum of 18 months of follow-up, the mean Glasgow Outcome Scores (GOSs) were 4.1 ± 1.4 and 4.7 ± 0.7 for patients with and without seizures, respectively. Cox's proportional hazards model showed that only the mean GCS on admission (P = 0.004, OR = 0.78, 95% CI = 0.67-0.93) was independently associated with seizures, and a decrease of one mean GCS increased the seizure rate by 21.6%. Conclusion: Lower mean GCS on admission is independently predictive of seizures, most of which occur within the first three months after CSDH.