, new research suggests.
Results from a multicenter, prospective cohort study showed 2.7% of nearly 1,500 participants with TBI reported also having posttraumatic epilepsy, and these patients had significantly worse outcomes than those without posttraumatic epilepsy.
“Posttraumatic epilepsy is common even in so-called mild TBI, and we should be on the lookout for patients reporting these kinds of spells,” said coinvestigator Ramon Diaz-Arrastia, MD, PhD, professor of neurology and director of the TBI Clinical Research Center, University of Pennsylvania, Philadelphia.
Dr. Diaz-Arrastia said he dislikes the term “mild TBI” because many of these injuries have “pretty substantial consequences.”
The findings were published online Dec. 29 in JAMA Network Open.
Seizures can occur after TBI, most commonly after a severe brain injury, such as those leading to coma or bleeding in the brain or requiring surgical intervention. However, there have been “hints” that some patients with milder brain injuries are also at increased risk for epilepsy, said Dr. Diaz-Arrastia.
To investigate, the researchers assessed data from the large, multicenter Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) database. Participants with TBI, defined as a Glasgow Coma Scale (GCS) score of 3-15, had presented to a level I trauma center within 24 hours of a head trauma needing evaluation with a CT scan.
The study included patients with relatively mild TBI (GCS score, 13-15), which is a “novel feature” of the study, the authors noted. Most prior studies of posttraumatic epilepsy focused on moderate to severe TBI.
The researchers included two sex- and age-matched control groups. The orthopedic trauma control (OTC) group consisted of patients with isolated trauma to the limbs, pelvis, and/or ribs. The “friend” or peer control group had backgrounds and lifestyles similar to those with TBI but had no history of TBI, concussion, or traumatic injury in the previous year.
The analysis included 1,885 participants (mean age, 41.3 years; 65.8% men). Of these, 1,493 had TBI, 182 were in the OTC group, and 210 were in the friends group. At 6- and 12-month follow-ups, investigators administered the Epilepsy Screening Questionnaire (ESQ), developed by the National Institute of Neurological Disorders and Stroke (NINDS).
Participants were asked about experiencing uncontrolled movements, unexplained changes in mental state, and repeated unusual attacks or convulsions, and whether they had been told they had epilepsy or seizures. If they answered yes to any of these questions, they received second-level screening, which asked about seizures.
Patients were deemed to have posttraumatic epilepsy if they answered affirmatively to any first-level screening item, experienced seizures 7 days after injury, and were diagnosed with epilepsy.
The primary outcome was rate of positive posttraumatic epilepsy diagnoses. At 12 months, 2.7% of those with TBI reported a posttraumatic epilepsy diagnosis compared with none of either of the control groups (P < .001).
This rate is consistent with prior literature and is “pretty close to what we expected,” said Dr. Diaz-Arrastia.
Among those with TBI and posttraumatic epilepsy, 12.2% had GCS scores of 3-8 (severe), 5.3% had scores of 9-12 (moderate), and 0.9% had scores of 13-15 (mild). That figure for mild TBI is not insignificant, said Dr. Diaz-Arrastia.
“Probably 90% of all those coming to the emergency room with a brain injury are diagnosed with mild TBI not requiring admission,” he noted.
The risk for posttraumatic epilepsy was higher the more severe the head injury, and among those with hemorrhage on head CT imaging. In patients with mild TBI, hemorrhage was associated with a two- to threefold risk of developing posttraumatic epilepsy.
“This prospective observational study confirms the epidemiologic data that even after mild brain injury, there is an increased risk for epilepsy,” said Dr. Diaz-Arrastia.