Research Reports - Unprovoked seizures after traumatic brain injury
Epilepsia. 2015 Sep;56(9):1438-44. doi: 10.1111/epi.13096. Epub 2015 Sep 2.
Mahler B(1), Carlsson S(2), Andersson T(3), Adelöw C(1), Ahlbom A(2), Tomson
OBJECTIVE: To quantify the risk of unprovoked seizures after traumatic brain
injury (TBI) METHODS: We used the Stockholm Incidence Registry on Epilepsy to
carry out a population-based case-control study, including 1,885 cases with
incident unprovoked seizures from September 1, 2000 through August 31, 2008,
together with 15,080 matched controls. Information of prior hospitalizations for
TBI was obtained through record linkage with the Swedish National Inpatient
Registry for the period 1980-2008. Relative risks (RRs) for unprovoked seizures
were estimated after various TBI diagnoses, and influences of TBI severity and
time since trauma were studied in detail.
RESULTS: After hospitalization for mild TBI, the RR was 2.0 (95% confidence
interval [CI] 1.5-2.7). The RR was higher after brain contusion (5.9, 95% CI
2.4-15.0) or intracranial hemorrhage (ICH) (4.5, 95% CI 2.2-9.0), whereas a
combination of both diagnoses led to a further sevenfold increase in RR (42.6,
95% CI 12.2-148.5). The risk was greatest during the first 6 months after severe
TBI (RR 48.9, 95% CI 10.9-218.9) or mild TBI (RR 8.1, 95% CI 3.1-21.7), but was
still elevated >10 years after any TBI.
SIGNIFICANCE: Herein we present a large population-based case-control study on
TBI as a risk factor for unprovoked epileptic seizures, including cases of all
ages with individually validated seizure diagnoses. The risk for epileptic
seizures was substantially increased after TBI, especially during the first
6 months after the injury and in patients with a combination of ICH and brain