What you need to know about - Seizures
It is estimated that seizures effect about ten percent of the population at one point in their lives. About 1% of these people have recurrent seizures, known as epilepsy.
Seizures are caused by an increase in synchronous neuronal discharge in the brain, leading to the brain being overloaded by stimuli. Epilepsy is defined as having two or more seizure episodes, and the seizures must not have a secondary cause. Everyone has a seizure threshold, and people with epilepsy typically have a lower threshold than normal. Seizures can cause a variety of symptoms, and this is mainly dependent on where the initial seizure focus is.
There are many organic causes of seizures. Metabolic derangements such as very low glucose or sodium can provoke seizures in both epileptics and non-epileptics. Certain medications and drugs also lower seizure threshold and can cause both primary seizures and seizures in those with epilepsy. For example, quinolone antibiotics and penicillins, tricyclic antidepressants, cyclosporine and isoniazid all lower the seizure threshold. Also, both alcohol intoxication and withdrawl can provoke new and recurrent seizures.
Other causes of first time seizures include degenerative brain disorders, strokes, brain tumors, brain trauma, syncope, and many others. Febrile seizures, occurring in those with very high fevers, generally occur in children only.
There are many types of seizures and they can be broken into two main categories - partial and generalized. Partial seizures originate at a specific focus in the brain and do not spread. These can be simple with no impairment in consciousness, or complex in which the patient may lose consciousness. Symptoms of partial seizures depend on the foci in the brain at which the seizure activity is located.
Generalized seizures involve the entire brain. Primary generalized seizures are diffuse and begin with the involvement of both cerebral hemispheres. In these seizures the Reticular Activating System (RAS) which controls consciousness and voluntary functions, is usually suppressed. Both grand mal (tonic-clonic) and petit mal (absence) seizures fall into this category.
Secondarily generalized seizures begin as partial focal seizures and spread to the rest of the brain. They can become tonic-clonic seizures.
There are many other specific types of epilepsy, which I will not discuss here. They all involve one or more types of the seizures above.
Treatment for seizures is vast and usually depends on the type of seizure or seizures involved. In general, treatment is typically begun after a patient has more than one seizure. Patients with epilepsy can go into remission - this is most common if the person has idiopathic epilepsy (in which a cause was never determined), the epilepsy developed in early to middle childhood, and in those with a normal neurologic exam. It is important to keep a person on anti-seizure medications for at least 2-5 years because this reduces the likliehood of relapse.