Epilepsy

Epilepsy is a tendency to have repeated seizures that are caused by disturbances in the normal electrical functions of the brain. These seizures can occur one at a time, or several may occur, one after another, with little recovery time in between. A seizure may affect a person’s consciousness, bodily movements or sensations.

Many individuals may have a single seizure at some point in their life – this is not epilepsy. Rather, epilepsy may be diagnosed if a person experiences repeated seizures.

There are many causes of seizures. Included are brain damaged by trauma or hemorrhage, tumor, developmental abnormality, problems with the chemicals that send signals from one neuron to another (neurotransmitters) and scar formation within the brain.

The symptoms of a seizure depend on the type of seizure. There are two main types of generalized seizures, tonic-clonic (grand mal) and absence (petit mal). In tonic-clonic seizures, there is sudden loss of consciousness followed by stiffening of the body and then generalized jerking of the arms and legs. There may be tongue biting and incontinence. These tonic-clonic seizures last for a few minutes and are usually followed by feelings of confusion.

Absence seizures are sudden blank spells. The patient stops moving, stares into space and may exhibit eye blinking. These spells may last for only a few seconds but occur throughout the day. Although this type of seizure is more common in children, it also occurs in adults.

Partial seizures are seizures that usually exhibit some sort of feeling prior to beginning (aura). In simple partial seizures, there is no loss of consciousness while the patient experiences uncontrolled movement of an arm, leg or both. Complex partial seizures are distinguished by confusion or loss of awareness that accompanies the seizure.

Finally, a partial seizure may progress to a tonic-clonic seizure. This is called a secondarily generalized partial seizure.

As always, a careful history and physical examination are the first steps in diagnosis. A second major tool is an electroencephalograph (EEG). This is a machine that records brain waves picked up by tiny wires taped to the head. Brain waves during or between seizures may show special patterns, which assist in the diagnostic process. Imaging modalities, such as MRI (magnetic resonance imaging), and to a more limited extent, CT (computerized tomography), performed with and without intravenous contrast material assist in identifying structural causes of seizures. PET (positron emission tomography) may be used in certain cases to measure how intensely certain parts of the brain use up glucose, oxygen, or other substances, which assists the practitioner in identifying areas of the brain that are producing seizures.