Authored by MCN Neurologists
A seizure is a brief electrical discharge of the brain that can result in a change in alertness, body movements, thoughts or sensations. If a seizure tends to recur, we then call it a seizure disorder or epilepsy. Epilepsy is simply the tendency to have recurrent seizures. Epilepsy does not imply any associated abnormalities and is very common.
Epilepsy, or a seizure disorder, occurs in 1-2% of the population. There are over 2.5 million Americans and over 60,000 Minnesotans with epilepsy. One in every 60 children has epilepsy and one child in every other classroom has a seizure disorder. Six to nine percent of the population will have a single seizure, which will not recur, and may not require medication treatment.
Causes of Seizures and Epilepsy
Epilepsy is caused by any condition that irritates the brain. Epilepsy may be caused by a brain tumor, stroke, vascular malformation or tangle of blood vessels in the brain, an infection, or bleeding in or around the brain. Serious head injuries and problems in development of the brain before birth may also result in epilepsy. Epilepsy can occur at any time of life. New seizures occur frequently in childhood, but there is increasing evidence that seizures in people over the age of 65 are also very common. In over half the individuals with epilepsy, no cause is determined. These seizures and seizure disorders are classified as idiopathic, meaning no cause has been identified.
Classification of Seizures
Seizures are classified into two types depending on where they begin. The partial seizures begin in one part of the brain and the generalized seizures affect the whole brain at once.
Simple Partial Seizures: Partial seizures are divided into two types, simple and complex, depending on whether alertness is maintained. Persons with simple partial seizures maintain consciousness while experiencing a wide range of symptoms, such as a sudden movement or a feeling.
Complex Partial Seizures: Complex partial seizures are associated with decreased awareness. An individual may make random movements with their arms or legs or stare and appear briefly unresponsive. Most seizures last only a few minutes. The individual may not remember what happened during the seizure and may be confused or sleepy afterwards. Sometimes, complex partial seizures may spread to involve the whole brain and become generalized seizures. These seizures were previously known as psychomotor or temporal lobe seizures.
Generalized Seizures: Generalized seizures affect the whole brain at once. Generalized tonic-clonic seizures, previously called grand mal seizures, may be associated with rhythmic movements of the arms and legs. The person may fall and stiffen with jerking movements of the extremities during the seizure. The generalized tonic-clonic seizure usually last just a few minutes. The individual may then be tired or confused, which is known as the postictal state.
Absence Seizures: Absence seizures, previously knowing as petit mal seizures, occur most frequently between the ages of 5 and 15. These seizures are very brief and start and end abruptly. The child may suddenly stop their activity, stare, or make lip-smacking movements.
Less frequent seizures include atonic seizures with loss of muscle tone resulting in a person suddenly dropping to the ground. Myoclonic seizures consist of brief muscle jerks or twitches. Infantile spasms occur in very young children, often in conjunction with other signs of brain abnormality.
Examination and Tests for Seizures and Epilepsy
A neurologist will take a history with a description of the seizures including the duration, frequency and any causes or triggers that may have been identified. A neurologist will seek information concerning any previous treatments, as well as a history of seizures in the family, early development and level of functioning. A neurologic examination is then performed. Additional testing will be performed to assist in the diagnosis of seizures. This may include an electroencephalogram (EEG), an MRI of the brain or a CT scan and other testing. Epilepsy is a clinical diagnosis, meaning that the diagnosis is made on the basis of the seizures that have occurred, with the testing being helpful in confirming the diagnosis. The appropriate treatment will be selected with discussion between the patient and the neurologist.
Treatment for Seizures and Epilepsy
Although there is no cure for epilepsy, most individuals achieve excellent control with antiepileptic drugs or anticonvulsant medications. The overwhelming majority of individuals do well with no seizures. Carbamazepine (Tegretol, Carbatrol), phenytoin (Dilantin), divalproic (Depakote) and phenobarbital have been used for many years to control seizures. More recently developed drugs include gabapentin (Neurontin), lamotrigine (Lamictal), topiramate (Topamax), tiagabine (Gabitril), levetiracetam (Keppra, Keppra XR), oxcarbazepine (Trileptal), zonisamide (Zonegran), felbamate (Felbatol), pregabalin (Lyrica), lacosamide (Vimpat) and rufinamide (Banzel). Each new antiepileptic drug has resulted in an improvement in seizure control in some individuals with previously uncontrolled seizures. Many of these drugs have been evaluated in clinical trials in which Minneapolis Clinic of Neurology neurologists have participated.
New technological advances including the Vagal Nerve Stimulator, an implantable device, have also enhanced seizure control. The very high-fat low-carbohydrate ketogenic diet has been found to have a limited effectiveness in controlling seizures in some children. Surgical treatment has improved seizure control in selected patients who are not responsive to medications.
Clinical trials utilizing new antiepileptic drugs in development are ongoing through the Midwest Center for Seizure Disorders at the Minneapolis Clinic of Neurology.
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