Abstracts

Rationale: Although traumatic brain injury (TBI), a well-established risk factor for post-traumatic epilepsy (PTE), is the signature injury incurred by the troops deployed in Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF), the risk and burden of epilepsy, particularly due to blast-related closed-head injuries, remain unknown. As a first step in examining this population, we aimed to characterize the clinical presentation of OIE/OEF veterans with both TBI and epilepsy/seizure in the VA Greater Los Angeles Health System (VAGLAHS).Methods: We used VA administration data to identify all veterans who were assigned an outpatient ICD-9 diagnosis of both epilepsy (epilepsy; convulsions) and TBI (skull or facial bone fracture; post-traumatic headache; intracranial injury; late effect, intracranial injury; unspecified face/neck injury; open wound of head) during an outpatient visit at VAGLAHS in 2008-2009. We then conducted a retrospective chart review of the electronic medical record to confirm these diagnoses and obtain further details regarding demographics, treatment, diagnostic work-up, comorbidity, and health care utilization. Two neurology physicians reviewed all charts independently (LC and JC).Results: There were 227 patients with diagnosis codes of both epilepsy and TBI. Only 18 veterans were from the OEF/OIF theatre, 3 of which had erroneous ICD coding (1 with panic attack and near syncope and 2 without seizures in record). All 15 patients studied in detail were male. The mean age was 30.4 years: 67% were white, 20% were working, 20% were students, and all were independent of ADL. 80% of the injuries sustained were combat-related. 80% suffered from blast-related injuries, the majority of which were caused by improvised explosive devises (9/12 patients, 75%). Only 3 patients (20%) were confirmed with the diagnosis of PTE; others either had a questionable clinical history, no supportive (or incomplete) objective data, or underlying complex comorbidity. A preponderance of patients (87%) had a diagnosis of post-traumatic stress disorder (PTSD). Nearly 50% (7/15) were suspected of having non-epileptic seizures, all of whom had a diagnosis of PTSD. Although 93% of patients had at least one outpatient visit in the neurology or epilepsy subspecialty clinic, most did not return for follow-up despite recommendations for further diagnostic work-up (8/14 patients, 57%).Conclusions: Amongst OIE/OIF veterans with a diagnostic code of epilepsy and TBI, blast exposure was the most common etiology of head trauma. Only 3 cases had confirmed PTE. Reasons for not being able to establish the diagnosis of epilepsy included incomplete diagnostic work-up, descriptions of complex overlapping symptomatology that may be attributable to TBI, underlying comorbidities, like PTSD, or in some cases suspected non-epileptic seizures. Future studies that examine the burden of PTE amongst OIE/OIF veterans with TBI need to account for possible limitations in ICD epilepsy/seizure codes given this potential complex symptomatology.