Chronic subdural hematomas and seizures: the role of prophylactic anticonvulsive medication.

BACKGROUND

The rates of seizure activity associated with surgical treatment of chronic subdural hematoma (CSH) reported in the literature has varied greatly. The efficacy of prophylactic anticonvulsive medication (ACM) has been debated and its use been erratic. With improved diagnosis, reduction of associated morbidity impacts greatly on the mortality rate, and so the use of ACM may be important to the patient with CSH.

METHODS

We conducted a retrospective analysis of the records of patients treated surgically for CSH and examined the prevalence of seizure activity, morbidity, and mortality and the effects of anticonvulsant medication.

RESULTS

Ninety-eight patients (65 = male) were identified with a mean age of 72 years and a range of 4 to 97 years. Six patients had a preexisting seizure disorder; despite therapeutic serum levels of ACM, 3 of these 6 patients experienced seizures without mortality. Seizures occurred in 20/98 (20.4%) patients during hospitalization or follow-up. Of the 92 patients without a preexisting seizure disorder, 42 (46%) received prophylactic phenytoin with therapeutic serum levels. One patient among the 42 (2.4%) who received prophylactic ACM experienced seizure activity in comparison to 16 of 50 (32%) patients who did not receive adequate prophylactic ACM (P = < 0.001). Six of 11 deaths within one month of discharge occurred in patients with a new onset of seizures (P = < 0.005). Age, sex, history of trauma, Markwalder scores on admission, location of hematoma, or type of surgery were unrelated to the occurrence of seizures or mortality. Following hospital discharge, patients were continued on ACM for a mean duration of 8 months without seizures.

CONCLUSIONS

The onset of new seizures was found in 17 (18.5%) of 92 patients and was associated with increases in morbidity and mortality. Patients who received prophylactic ACM demonstrated a significant decrease in the occurrence of seizures, and we therefore recommend the use of phenytoin prophylaxis in patients treated surgically for chronic subdural hematoma.