- CONDITION CENTERS
Epilepsy is a chronic neurologic disorder characterized by episodes of recurrent, unprovoked seizures because the neurons in the brain signal abnormally. In most cases, there is no known cause for the occurrence of these seizures. It is estimated that more than 50 million people worldwide have epilepsy. Two million people in the United States are afflicted with the condition; 300,000 are under the age of 14 and more than 500,000 are over age 65.1
Approximately 80% of patients diagnosed with epilepsy respond to some form of pharmacologic and/or surgical intervention. The other 20%, however, do not respond to any treatment and continue to have seizure episodes.1
Not every person who has a seizure is said to have epilepsy. In some cases, nonepileptic seizures occur as a result of an injury or a medical condition not related to epilepsy. The onset of epilepsy can occur in a patient with or without risk factors. Nearly 10% of all individuals will have at least 1 seizure in their lifetime (Table 1).
The International Classification of Epilepsies and Epileptic Syndromes has distinguished various types of epilepsy based on the accompanying symptoms or the region of the brain where they occur.1 The most common form is temporal lobe epilepsy. Other forms include the following2:
The following other epilepsy syndromes typically are developed during childhood:
When the exact cause of epilepsy is unknown, it is referred to as idiopathic epilepsy. When the cause of epilepsy is due to a detectable factor, it is known as symptomatic epilepsy. Whereas the exact cause of some forms of epilepsy is unknown, there are many identifiable factors that may contribute to its manifestation (Table 2). The occurrence of epilepsy is very prevalent in childhood or after age 60, but it may occur at any age.
Possible causes of epilepsy include the following:
Factors that may trigger seizures in epileptic patients are as follows:
When a patient experiences a seizure, medical attention should be sought immediately. In cases where there is no identifiable cause of the seizures and the seizures are recurring, a diagnosis of epilepsy is confirmed. A neurologic assessment of the patient is performed, using such diagnostic tools as the electroencephalogram, computed tomography scan, or magnetic resonance imaging to confirm the epilepsy diagnosis. In some cases, hematologic tests, such as complete blood cell and electrolyte analysis, are obtained to ascertain whether the impetus may be a systemic imbalance.
Types of Seizures
Seizures generally are divided into 2 categories: generalized and partial. Generalized seizures affect the entire brain region and may result in a loss of or some alteration of consciousness. Partial seizures (focal seizures) occur in a single region of the brain but may spread to other regions. These seizures are sometimes accompanied by an aura (a warning sign, such as a smell, sound, or sensation). Complex partial seizures occur in 40% of all cases of epilepsy in adults. Another 20% experiences simple partial seizures, and still another 20% experiences generalized tonic?clonic seizures. Another 10% of the patient population experiences absence seizures, and the final 10% has the other types of seizures (Table 13).
Once the diagnosis of epilepsy has been confirmed, a treatment plan should be established with the following components:
The goal of all treatments available for epilepsy is to control or eradicate seizures, while enabling the patient to maintain a relatively normal lifestyle. Currently, the forms of treatment available for epileptics include pharmacologic therapy, diet regimens, and neurosurgery.
The first treatment of choice is drug therapy. There are numerous classes of pharmacologic therapies available to treat patients with epilepsy; however, the choice of therapy is dependent on the type of epilepsy. The majority of epileptic patients respond to drug therapy. According to the Epilepsy Education Association, 50% to 80% of all patients can be controlled with the correct choice of therapy.4 Some patients may respond to monotherapy, whereas others require combination therapy to remain seizure-free. Although these agents will not cure the disorder, they can aid the patient by eliminating or decreasing the incidence of seizure episodes without hindering the patient with undesirable adverse effects (Table 2).
In the 1990s, new drugs were approved by the FDA to aid in the treatment of epilepsy. They are often referred to as second-generation anticonvulsants and are typically used in conjunction with a first-generation agent for the treatment of partial seizures. These agents usually do not require laboratory monitoring of therapeutic levels (Tables 3 and 45,6).
In 1996, the FDA approved fosphenytoin (Cerebyx), which is a prodrug; its active metabolite is phenytoin. It is intended for short-term parenteral administration whenever other means of phenytoin are not available, are inappropriate, or are less beneficial. It is reserved for use in the control of generalized convulsive status epilepticus or prevention and treatment of seizures during neurosurgery.
Some patients have successfully responded to a type of diet known as the ketogenic diet. This diet is used in children 10 years and under who have a history of uncontrolled seizures. Essentially, the diet changes the manner in which the patient?s body utilizes energy from its nutritional sources. The diet is high in fat and low in carbohydrates, with no sugar allowed. It attempts to change the body?s primary energy source from glucose to fat. The diet requires strict compliance to be effective. The meals have specified amounts of fats, carbohydrates, proteins, and liquids and are taken from an approved list of foods. Usually, a vitamin and mineral supplement is recommended. This diet is to be used under direct medical supervision. Children need to be monitored closely while on this diet.1 It is important to note that this diet does not work for all patients.
Vagus Nerve Stimulator
In 1997, the FDA approved the use of a vagus nerve stimulator for patients with a history of uncontrolled seizures, even with the use of medications. The device is implanted subcutaneously in the upper left side of the chest and is attached to the vagus nerve in the lower neck. The device transports a burst of electrical energy from the vagus nerve to the brain. The stimulator is intended for patients 12 years and older, and the batteries in this device are replaced about every 5 years. It has been shown to reduce seizure activity by 20% to 40% in some individuals.2
Approximately 20% of patients with epilepsy will keep having seizures despite intervention with pharmacologic agents. For patients with uncontrolled seizures despite the efforts of pharmacologic agents, surgery may be considered. The ultimate goal of surgery is to excise the part of the brain that is responsible for provoking the seizures. There are various types of procedures, but the most commonly performed surgery is a temporal lobectomy.
The Role of the Pharmacist
Although epilepsy is a common disorder, it is still a very misunderstood condition. Continuous advances in research give more hope to patients. People with epilepsy can have normal and productive lives because of the numerous treatment options that are available. Pharmacists are key to providing the patient with proper counseling, monitoring of medication profiles, and stressing the importance of patient compliance.
1. Epilepsy/Seizures. Neurology Channel Web site, 2003. Available at: www.neurologychannel.com/epilepsy.
2. Seizures and Epilepsy: Hope Through Research. National Institute of Neurological Disorders and Stroke Website, 2003. Available at: www.ninds.nih.gov/health_and_medical/pubs/seizures_and_epilepsy_htr.htm.
3. Seizures and Epilepsy—Optimizing Patient Management. Medscape Web site, 2003. Available at: www.medscape.com/viewarticle/407196.
4. General Information About Epilepsy. Epilepsy Education Association Inc Web site, 2003. Available at: www.iupui.edu/~epilepsy.
5. Lacy C, Armstrong L, Ingrim N, Lance L. Drug Information Handbook. 11th ed.2003-2004. Hudson, Ohio: Lexi-Comp Inc;2003.
6.Physician’s Desk Reference. 56th ed. Montvale, NJ: Medical Economics; 2002.