The nature of posttraumatic epilepsy

Abstract

The development, recession and residua of posttraumatic epilepsy follow natural laws that are imperfectly defined. Studies from World War I, World War II, the Korean conflict and the Vietnam War demonstrate the following patterns: The onset of seizures is significantly related to local brain destruction and its location, and to diffuse brain damage, reflected by alteration in consciousness. The incidence of seizures has remained the same from 1 war to another, in spite of marked improvement in patient transport, surgical techniques, medical management and the prophylactic use of anticonvulsants in Vietnam. After injuries incurred in combat and support activities, the onset of new cases of epilepsy rises sharply, with approximately 5% having a seizure in the 1st week, 10% in the first 3 mo., 16% in the first 6 mo., 23% in the 1st yr, 29% in the first 2 yr; after that there is a low, but protracted rate of new cases of epilepsy. Those cases that occur in the 1st wk are less influenced by the agent of injury or local brain damage, thereafter there is a sharp divergence with the more extensive injuries providing the greater number of patients with seizures. In the population at risk, 65%-75% never have a seizure. In those that do, the development varies in degree, adjudged from frequency of seizures. The latter ranges from a single seizure to a number that defies an accurate count. As new patients with seizures accumulate, earlier patients cease having seizures. Within 5-10 yr, 1/2 of the patients have ceased having seizures, with or without therapy. Half of the remainder, about 8% of the injured, have intractable seizures. While there is a clear correlation between severity of injury and onset of seizures, there is no correlation between severity of injury and cessation of attacks. There is a correlation between the attack frequency and persistence of seizures. From the preceding, 2 principal determinants are evident: the constitutional tendency toward seizures (probably a multifactorial genetic trait), and the brain damage. In onset of seizures, both play a part, the constitutional factor apparently determining severity of attacks. In cessation or persistence of seizures, the constitutional factor plays the dominant role.