Seizures, Epilepsy, and Status Epilepticus

A seizure is a transient event caused by abnormal excessive or synchronous neuronal activity in the brain. Normally, excitatory glutamatergic signals and inhibitory GABAergic signals balance one another. When that balance shifts toward excitation, neurons can discharge together in a hypersynchronous pattern. The activity may begin in one network and remain focal, or spread bilaterally and produce a generalized seizure. A seizure is an event; epilepsy is a disease condition defined by an enduring tendency to have epileptic seizures. Epilepsy is diagnosed when any one of these criteria is met: - Two unprovoked, or reflex, seizures occurring more than 24 hours apart. - One unprovoked or reflex seizure plus an estimated probability of further seizures of at least 60% during the next 10 years. - An identified epilepsy syndrome. A seizure caused by hypoglycaemia, acute electrolyte disturbance, intoxication, withdrawal or an acute brain injury may be provoked rather than evidence of epilepsy. The cause still requires urgent attention, but the diagnostic meaning is different. “Resolved” epilepsy is not necessarily a permanent cure. The term may apply to a person whose...