Typically it is safe to complete the work-up following a single seizure as an outpatient. In many, with what appears to be a first seizure, other minor seizures have previously occurred.Up to 10% of people have at least one epileptic seizure. Provoked seizures occur in about 3.5 per 10,000 people a year while unprovoked seizures occur in about 4.2 per 10,000 people a year. After one seizure, the chance of experiencing a second is about 50%. Epilepsy affects about 1% of the population at any given time with about 4% of the population affected at some point in time. Many places require people to stop driving until they have not had a seizure for a specific period. Signs and symptoms
The signs and symptoms of seizures vary depending on the type. The most common and stereotypical type of seizure is convulsive (60%), typically called a tonic-clonic seizure. Two-thirds of these begin as focal seizures prior to developing into tonic-clonic seizures. The remaining 40% of seizures are non-convulsive, an example of which is absence seizure. When EEG monitoring shows evidence of a seizure, but no symptoms are present, it is referred to as a subclinical seizure. Focal seizures
Focal seizures often begin with certain experiences, known as an aura. These may include sensory (including visual, auditory, etc.
Atonic seizures involve the loss of muscle activity for greater than one second. This typically occurs bilaterally (on both sides of the body). Duration
A seizure can last from a few seconds to more than five minutes, at which point it is known as status epilepticus. Most tonic-clonic seizures last less than two or three minutes. Absence seizures are usually around 10 seconds in duration. Postictal
After the active portion of a seizure, there is typically a period of confusion called the postictal period before a normal level of consciousness returns. This usually lasts 3 to 15 minutes but may last for hours. Other common symptoms include: feeling tired, headache, difficulty speaking, and abnormal behavior. Psychosis after a seizure is relatively common, occurring in between 6 and 10% of people. Often people do not remember what occurred during this time. Causes
Seizures have a number of causes. Of those who have a seizure, about 25% have epilepsy. A number of conditions are associated with seizures but are not epilepsy including: most febrile seizures and those that occur around an acute infection, stroke, or toxicity. These seizures are known as "acute symptomatic" or "provoked" seizures and are part of the seizure-related disorders. In many the cause is unknown. Different causes of seizures are common in certain age groups. Seizures in babies are most commonly caused by hypoxic ischemic encephalopathy, central nervous system (CNS) infections, trauma, congenital CNS abnormalities, and metabolic disorders.