Seizures and Status Epilepticus

Abstract

Seizures are caused by abnormal excessive synchronous discharges of cortical neurons which produce a sudden change in neurological function. Seizures may be generalized, focal, or focal onset with secondary generalization.

Generalized seizures involve both hemispheres of the brain simultaneously. They usually cause a decline in level of consciousness and can be tonic, atonic, clonic, or tonic-clonic or nonmotor (e.g., absence seizures). Focal seizures are also known as partial seizures and originate from a lateralized focus in the brain. Simple partial seizures feature no impairment in the level of consciousness, whereas complex partial seizures are characterized by impairment of consciousness.

Most seizures last many seconds to minutes, but persistent seizure activity (status epilepticus) can also occur. Status epilepticus can be convulsive or nonconvulsive. Convulsive status epilepticus is variably defined as continuous seizure activity lasting 5–30 min or as two or more serial seizures without return to normal level of consciousness in between episodes (interictally). Patients with nonconvulsive status epilepticus may appear confused or aphasic or have a profoundly depressed sensorium. The diagnosis of nonconvulsive status epilepticus is made by a combination of clinical features and EEG findings.

It is important that the initial evaluation and stabilization of the patient take place in an expeditious and systematic manner. Important considerations include placing the patient in the recovery position as soon as possible. With ongoing seizures, pharmacological management proceeds in a stepwise fashion per a defined treatment algorithm. Investigations enable a determination of whether seizures were provoked or not. Neuroimaging might reveal a culprit structural brain lesion that may eventually be amenable to epilepsy surgery.

If the episode represents a first-time seizure, several features and factors play a role in determining whether antiepileptic medications should be prescribed.