Generalized convulsive status epilepticus. A previously healthy 19-year-old woman was brought to the emergency department (ED) for a witnessed "convulsion." She had suddenly stopped talking and stared into space in the middle of a conversation with her roommates. She then exhibited stereotypical picking behavior of her clothes followed by head deviation to the right and generalized tonic-clonic arm and leg movements lasting approximately 3 minutes. She was not incontinent but she did bite her tongue. Emergency medical services (EMS) were activated and immediately transferred her to the closest ED, where she was found to be lethargic with a temperature of 101.3°F. The rest of her vitals were within normal limits. She had bilaterally reactive pupils to light, an intact oculocephalic reflex, and intact corneal reflexes. She localized to painful stimulation with the left arm but did not move the right side. Her tone was decreased on the right side with a positive Babinski sign. The remainder of her neurologic examination was unremarkable. An admission chest radiograph and head computed tomography (CT) were unrevealing. On returning from the CT imaging, the patient had a second generalized tonic-conic seizure witnessed by the ED staff which lasted slightly more than 5 minutes.
What is the most likely diagnosis in this patient?
The clinical presentation is most consistent with secondary generalized convulsive status epilepticus (GCSE). For practical purposes, most practitioners would categorize any seizure lasting at least 5 minutes or two or more discrete seizures without recovery of consciousness in between seizures as status epilepticus (SE).1-6 This cutoff is based on animal and human data suggesting irreversible neuronal injury7 and pharmacoresistance2,8,9 may occur after prolonged seizures and the observation that most clinical and electrographic seizures that do not progress to SE last less than 5 minutes.1,10-12 The clinical presentation of GCSE is typically relatively characteristic; however, postanoxic myoclonus (see detailed discussion below), posturing during herniation, and psychogenic seizures may be considered in the differential diagnosis.
GCSE is a relatively common neurologic emergency with an overall estimated incidence of 41 to 61 cases per 100,000 patients per year.13 Rapid diagnosis is crucial since untreated SE rapidly becomes refractory to therapy and carries significant morbidity and mortality rates. GCSE is defined as generalized convulsions that are associated with rhythmic jerking of the extremities.14 Classic clinical features include generalized tonic-clonic movements or rhythmic jerking of the extremities and mental status impairment (coma, lethargy, confusion); additional neurologic findings may include aphasia, amnesia, staring, automatisms, blinking, facial twitching, agitation, nystagmus, eye deviation, and perseveration. After convulsions have ceased, focal findings such as focal motor impairment, also known as Todd paralysis, may persist.
A number of different classification schemes have been proposed to categorize SE into subtypes based on clinical and electrographic characteristics. For practical purposes, we will focus on convulsive and nonconvulsive ...