Posttraumatic epilepsy risk factors: one-year prospective study after head injury.

PURPOSE: Prospective evaluation of risk factors for posttraumatic epilepsy (PTE) by using clinical, EEG, and brain computed tomography (CT) data in four assessments from the head injury (HI) acute phase to 1 year later; and evaluation of the possible epileptogenic role of hemosiderin as shown by brain magnetic resonance imaging (MRI).

METHODS: Risk factors for PTE were evaluated by using Kaplan-Meier curves, log-rank test, and the Cox model in 137 consecutively enrolled adult inpatients. Percentage differences of patients with brain hyperintense and/or hemosiderin areas shown by MRI 1 year after HI were statistically evaluated by univariate tests considering two subgroups [e.g., patients with (PTE) and without (WLS) late seizures].

RESULTS: The PTE subgroup included 18 patients with at least two seizures between the second and twelfth months. Kaplan-Meier curves demonstrated that Glasgow Coma Scale low score, early seizures, and single brain CT lesions are PTE risk factors, as is the development of an EEG focus 1 month after HI. No significant percentage difference was found between PTE and WLS patients with hemosiderin spots shown by MRI 1 year after HI.

CONCLUSIONS: the Cox model indicates that, for HI patients with early seizures and brain CT single temporal or frontal lesions in the acute phase, the PTE risk is 8.58 and 3.43 times higher, respectively, than for those without. An EEG focus 1 month after HI is a risk factor 3.49 times higher than for patients without such EEG changes. One year after HI, a higher percentage of PTE than WLS patients had cortical MRI hyper-intense areas including hemosiderin.