Risk Factors and Outcomes of Late Posttraumatic Seizures in Combat-Related Traumatic Brain Injury

Introduction: Post-traumatic seizures (PTSs) contribute to morbidity after traumatic brain injury (TBI). Early PTS are rare in combat casualties sustaining TBI, but the prevalence of late PTS is poorly described. We sought to define the prevalence and risk factors of late PTS in combat casualties with computed tomography evidence of TBI. Methods: From 2010 to 2015, 687 combat casualties were transferred to a military treatment facility and included in the Department of Defense Trauma Registry. 71 patients with radiographic evidence of TBI were analyzed. Data collection included demographics, injury characteristics, interventions, medications, and outcomes. Results: Of the 71 patients with evidence of TBI, 66 patients survived hospitalization and were followed. No patients had early PTS, and most received antiepileptic drugs (AEDs) for prophylaxis. At a median follow-up of 7.4 y, late PTS occurred in 25.8% of patients. Patients with late PTS were more severely injured (median Injury severity score 30 versus 24, P = 0.005) and required more blood products (18 units versus 2, P = 0.045). Patients with late PTS were more likely to have had a penetrating TBI (76.5% versus 38.8%, P = 0.01), multiple types of intracranial hemorrhage (94.1% versus 63.3%, P = 0.02), and cranial decompression (76.5% versus 28.6%, P = 0.001). Six-month Glasgow outcome scores were worse (3.5 versus 4.1 P = 0.001) in the late PTS population. No significant relationship was observed between administration of AEDs for early PTS prophylaxis and late PTS. Conclusions: Combat casualties with TBI suffering late PTS are more severely injured and require more blood products. Penetrating TBI, intracranial hemorrhage, and need for cranial decompression are correlated with late PTS, and associated with worse Glasgow Outcome Score. The administration of prophylactic AEDs for early PTS was not associated with a difference in rates of late PTS.