Epilepsy
Overview
Epilepsy is a chronic neurological condition characterized by recurrent seizures that are caused by abnormal cerebral nerve cell activity. Epilepsy is classified as idiopathic or symptomatic.
Idiopathic epilepsy has no known cause, and the person has no other signs of neurological disease or mental deficiency. Symptomatic epilepsy results from a known condition, such as stroke, head injury, poisoning, Lennox-Gastaut syndrome, and cerebral palsy.
Incidence and Prevalence
More than 2 million people in the United States and over 50 million worldwide suffer from epilepsy. In the United States, more than 300,000 people with epilepsy are under the age of 14, and more than 500,000 are over the age of 65.
Seizure
A nerve cell transmits signals to and from the brain in two ways by (1) altering the concentrations of salts (sodium, potassium, calcium) within the cell and (2) releasing chemicals called neurotransmitters (gamma aminobutyric acid). The change in salt concentration conducts the impulse from one end of the nerve cell to the other. At the end, a neurotransmitter is released, which carries the impulse to the next nerve cell. Neurotransmitters either slow down or stop cell-to-cell communication (called inhibitory neurotransmitters) or stimulate this process (called excitatory neurotransmitters).
Normally, nerve transmission in the brain occurs in an orderly way, allowing a smooth flow of electrical activity. Improper concentration of salts within the cell and overactivity of either type of neurotransmitter can disrupt orderly nerve cell transmission and trigger seizure activity.
Certain areas of the brain are more likely than others to be involved in seizure activity. The motor cortex, which is responsible for body movement, and the temporal lobes, including the hippocampus, which is involved in memory, are particularly sensitive to biochemical changes (e.g., decreased oxygen level, metabolic imbalances, infection) that provoke abnormal brain cell activity.
Seizure Phases-A seizure often has three distinct phases: aura, ictus, and postictal state. The first phase involves alterations in smell, taste, visual perception, hearing, and emotional state. This is known as an aura, which is actually a small partial seizure that is often followed by a larger event. The seizure is known as ictus. There are two major types of seizure: partial and generalized. What happens to the person during the seizure depends on where in the brain the disruption of neural activity occurs. Following a seizure, the person enters into the postictal state. Drowsiness and confusion are commonly experienced during this phase. The postictal state is the period in which the brain recovers from the insult it has experienced.
Types
The International Classification of Epileptic Seizure identifies seizure types by the site of origin in the brain. The two main categories of seizures include partial seizures and generalized seizures. A partial seizure can evolve to a generalized seizure. There are several subtypes of each. Only the most common are described here.
Partial Seizures
The site of origin is a localized or discreet area in one hemisphere of the brain. The two most common types of partial seizure are simple partial and complex partial.
Simple Partial-These produce symptoms associated with the area of abnormal neural activity in the brain: motor signs, sensory symptoms, autonomic signs and symptoms (involuntary activity controlled by autonomic nervous system), and psychic symptoms (altered states of consciousness). There is no impairment of consciousness in simple partial seizures. Complex Partial-Impairment of consciousness, characteristic of complex partial seizures (CPS), results in the inability to respond to or carry out simple commands or to execute willed movement, and a lack of awareness of one's surroundings and events. Automatisms may occur. An automatism is a more or less coordinated, involuntary motor activity. A simple complex seizure may begin as a simple partial seizure.
Generalized Seizures
At the onset, seizure activity occurs simultaneously in large areas of the brain, often in both hemispheres. Seizures can be convulsive or nonconvulsive. The two most common types are tonic-clonic and absence.
Tonic-clonic (grand mal) -There is loss of consciousness during the seizure. The tonic phase, consisting of increased muscle tone (rigidity), is followed by the clonic phase, which involves jerking of the extremities. Automomic symptoms may also be present.
Absence (petit mal) -This type occurs most often in children, usually beginning between the ages of 5 and 12 years and often stopping spontaneously in the teens. The loss of consciousness is so brief that the child usually does not even change position. Most absence seizures last 10 seconds or less. There is no postictal state, but the person usually lacks awareness of what occurs during the seizure.
Myoclonic-These seizures are so brief that they may go unnoticed. They involve sudden muscle contractions that occur much more rapidly than clonic activity and are often confused with tics. Myoclonic seizures occur at all ages and are associated with epileptic syndromes such as West syndrome and Lennox-Gastaut syndrome.
Syndrome- and Situation-Related Epilepsy
Infants and Children-Epilepsy is one of several symptoms that occur in West syndrome and Lennox-Gastaut syndrome. West syndrome, also called infantile spasm, is a rare disorder of infancy and early childhood. It is characterized by epilepsy, hydrocephalus, congenital anomalies, and mental retardation.
Lennox-Gastaut syndrome usually develops between the ages of 1 and 8 years old and is characterized by atonic, absence, and myoclonic seizures. Many of these children are developmentally delayed and have behavioral problems.
Adults-Several medical conditions may precipitate epilepsy in adults, notably withdrawal from chronic alcohol and drug abuse, eclampsia, and stroke.
Signs and Symptoms
Signs and symptoms depend on the area of the brain in which seizure activity occurs and on the type of seizure.
Simple Partial Seizures Symptoms may be motor, sensory, psychic (states of consciousness), and/or autonomic (involuntary activity controlled by the autonomic nervous system). There is no impairment of consciousness in simple partial seizures. Motor signs include the following:
- alternating contraction and relaxation of muscle groups
- eye movements and turning of the head to the same side
- asymmetrical posturing of the limbs
- speech arrest, vocalization
Sensory symptoms include the following:
- seeing flashes of lights or colors, illusions and hallucinations
- hearing humming, buzzing, hissing noises
- experiencing unpleasant odors and tastes
- dizziness, lightheadedness
Autonomic signs and symptoms include the following:
- borborygmi (rumbling noises produced by gas in the intestines)
- flushing
- incontinence
- nausea, vomiting
- piloerection (goose bumps)
- pupillary dilation
- sweating
- tachycardia (rapid heart rate)
Psychic symptoms include the following:
- detachment, depersonalization
- dreamy state
- memory distortion: flashback, deja vu (feeling that one has seen something before), deja entendu (feeling that one has heard something before), jamais vu (feeling that one has never seen something that is familiar), jamais entendu (feeling that one has never heard something that is familiar), panoramic vision (rapid recall of past events)
- time distortion
- unprovoked emotion: fear, pleasure, displeasure, depression, anger, elation, eroticism
Complex Partial Seizures Loss of consciousness distinguishes complex partial seizures from simple partial seizures. While unconscious, the patient may have "vacant" or "frightened" look and may have signs and symptoms of a simple partial seizure. Automatisms may occur during unconsciousness.
There are five types of automatisms:
- Alimentary: chewing, increased salivation, borborygmi (rumbling noises caused by gas in the intestines)
- Mimetic: facial expressions of fear, bewilderment, discomfort, tranquility, laughter, crying
- Gestural: repetitive movements of the hands, fingers, sexual gestures
- Ambulatory: wandering, running
- Verbal: repeated short phrases or swearing
Patients who have had complex partial seizures over a period of years may develop drop attacks. When this occurs, they lose postural tone and fall with the sudden onset of unconsciousness.
Complications-Complex partial seizures are easily triggered by emotional stress. The limbic structures (i.e., hypothalamus, hippocampus, amygdala) of the brain may be damaged by seizure activity. The limbic system is concerned with emotion and motivation.
These patients may develop cognitive and behavioral difficulties, such as the following:
- Interictal personality: humorlessness, dependence, obsessions, anger, hypo- or hypersexuality, emotionality
- Memory loss: short-term memory loss attributable to dysfunction in the hippocampus, anomia (inability to recall words or names of objects)
- Poriomania: prolonged aimless wandering followed by amnesia
- Violent behavior: aggression and defensiveness when subjected to restraint during a seizure
Tonic-Clonic (Grand Mal) Seizures
Generalized tonic-clonic seizures may begin as simple or complex partial seizures. They may begin with aura, but patients often do not remember this phase. The tonic phase consists of the following:
- Fall
- Loss of consciousness
- Yell or "tonic cry"
- Extension of arms, legs, and/or face
- Fingers and jaw clenched
- Autonomic symptoms: increased blood pressure and heart rate, increased bladder pressure, flushing, sweating, increased salivation, increased bronchial secretion, apnea (cessation of breathing)
During the clonic phase, muscles relax completely, then muscle tone returns. This produces rhythmic jerks of the body and head. In the postictal phase drooling; biting of the tongue, cheek, or lip; and urinary incontinence are common.
When the jerking movements stop, the patient may remain unconscious for a period of time. The seizure usually lasts 5 to 20 minutes. Patients often awaken confused and may sleep or pass directly into sleep without awakening, and may experience prolonged weakness after the event.
Complications-A tonic-clonic seizure may involve injury, such as
- aspiration of secretions or vomited stomach contents
- skull or vertebral fractures
- tongue, lip, or cheek injuries caused by biting
- status epilepticus
Status epilepticus is a medical emergency in which seizures recur without the patient regaining consciousness between events. It is also defined as a single seizure that lasts 30 minutes or longer. This condition can develop in any type of seizure but is most common in tonic-clonic seizures. Status epilepticus may cause brain damage or cognitive dysfunction and may be fatal.
Subsequent seizures become briefer, more localized, and may be reduced to myoclonic activity. Events may include:
- aspiration
- cardiac arrhythmias
- dehydration
- fractures
- myocardial infarction (heart attack)
- oral and head trauma
- pulmonary edema (fluid build-up in the lungs)
Absence (Petit Mal) Seizures
This type affects children. Absence seizures are generalized seizures that have a rapid onset and are characterized by the following:
- automatisms (e.g., licking the lips, chewing, grimacing, scratching, fumbling with clothes)
- blank staring
- change in facial expression
- lack of awareness, responsiveness, memory
- jerking movements of the extremities
- postictal confusion, sense of "lost" time
Myoclonic Seizures
These brief seizures cause a sudden onset of muscle contractions that may occur throughout the body or may be limited to certain areas of the body (e.g., face, one or more extremities, individual or groups of muscles). The seizure is so brief that it is not known if consciousness is lost. The onset may be so sudden that the patient falls to the ground, or so subtle that the seizure looks like a tremor.
SUDEP
Sudden unexplained death in epilepsy (SUDEP) occurs in a small percentage of persons with epilepsy. For reasons that are poorly understood, an otherwise healthy person with epilepsy can die suddenly. While this also happens within the general population, persons with symptomatic epilepsy have a much greater risk.
Autopsies have not uncovered a physical cause of SUDEP. It is possible that pulmonary edema (fluid build-up in the lungs), suffocation, or cardiac arrhythmias (irregular heartbeat) may be responsible. Some people appear to be at a higher risk than others, such as young adults with generalized tonic-clonic seizures that are not fully controlled with medication and those who abuse alcohol and illicit drugs. Patients using two or more anticonvulsants may be at increased risk for SUDEP.
Causes and Risk Factors
Many abnormalities of the nervous system can result in seizure activity. Seizures can also occur in the normal nervous system when its metabolic balance is disturbed. The cause (etiology) of epilepsy may be not clearly known (idiopathic) or related to a particular disease state. About 35% of all cases of epilepsy have no clearly definable cause.
Genetic Factors
Some persons may have a genetic predisposition to the development of seizures. There is also an increased incidence of epilepsy in relatives of those with a seizure disorder.
Head Injury
Seizures may develop at or around the time of injury or years after (usually not more than 2 years later).
Stroke
Seizures can occur at the time of a stroke or many years later. They may occur with strokes that result in lack of blood flow to the brain or with those that involve bleeding (hemorrhage) into or around the brain.
Metabolic Disturbances
Disorders that change levels of various metabolic substances in the body sometimes result in seizures.
- Altered levels of sodium, calcium, or magnesium (electrolyte imbalance)
- Kidney failure with increased urea in the blood (uremia) or changes that occur with kidney dialysis
- Low blood sugar (hypoglycemia) or elevated blood sugar (hyperglycemia)
- Lowered oxygen level in the brain (hypoxia)
- Severe liver disease (hepatic failure) and elevation of associated toxins
Toxins
Overdose of and abrupt withdrawal from some prescription drugs can result in seizure activity. Substances that may induce seizures include the following:
- Antipsychotic medications (e.g., chlorpromazine, haloperidol, clozapine)
- Aminophylline (bronchodilator; Phyllocontin®, Truphylline®)
- High doses of penicillin
- Lithium (Eskalith®)
- Tricyclic antidepressants (Elavil®, Limbitrol®, Tofranil®)
Chronic illicit drug use also may cause seizures, particularly cocaine, heroine, amphetamines, and PCP. Alcohol withdrawal can produce seizures, which usually occur 12-24 hours after the last drink but can occur up to 48 hours or more after binge drinking. Poisoning from carbon monoxide, lead, and other heavy metals also may cause seizures.
Infections
Infections of the nervous system may result in seizure activity. These include infection of the covering of the brain and the spinal fluid (meningitis), infection of the brain (encephalitis), and human immunodeficiency virus (HIV) and related infections.
Tumors
Cancerous (malignant) and benign brain tumors may be associated with seizures. The location of the lesion influences the risk.
Degenerative Disorders
Several neurodegenerative disorders produce seizure activity, including the following:
- Alzheimer's disease
- Creutzfeld-Jakob disease
- Neurofibromatosis
- Phenylketonuria (PKU)
- Tuberous sclerosis
- Sturge-Weber syndrome
- Tay-Sachs disease
Cerebral Palsy
Epilepsy is often a symptom of cerebral palsy, which results from lack of oxygen, infection, or trauma during birth or infancy.
Febrile Seizures
Febrile seizures occur in small children and are caused by high fever. From birth up to the age of 5, about 2% to 4% of children in the United States experience a febrile seizure. Approximately one-third of these children may experience another febrile seizure, but only a few develop epilepsy.
Triggers
Triggers do not cause seizures but provoke the onset of a seizure or cause a seizure in a patient whose epilepsy is under control. Alcohol consumption, hormonal changes of the menstrual cycle, sleep deprivation, flickering or flashing light, and stress can trigger a seizure in a susceptible person.
Diagnosis
Patients should be evaluated thoroughly after their first seizure. It is imperative that the physician obtains a complete patient history, including details of birth, childhood, family history, and medication regimen; a thorough medical history, including illnesses of the nervous system; and a thorough history of drug and alcohol use.
A detailed description of the seizures is important to distinguish seizure types. Significant information includes the following:
- events that occurred during the seizure
- nature of the onset of the seizure
- presence of triggers (e.g., flickering light, sleep deprivation, dehydration)
- time of day of the seizure
- whether the seizure occurred during wakefulness or sleep
- whether awareness returns immediately or there is a prolonged period of confusion
Thorough physical and neurological examinations also are performed. Laboratory studies of blood and urine help identify liver and kidney dysfunction, which may (1) augment adverse effects of antiepileptic drugs and (2) rule out or identify certain underlying causes. These results also establish a baseline for monitoring kidney and liver function while the patient is on antepileptic medication. The kidney and liver metabolize most of these medications.
Differential Diagnosis
It is important to identify and treat any injury or disease process that may be producing seizures, such as
- head trauma,
- infection (e.g., encephalitis, meningitis), and
- drug intoxication or withdrawal.
Conditions that produce symptoms similar to those that occur during seizures must be ruled out, such as the following:
- Breath-holding spells: bluish tint to the skin (cyanosis), loss of consciousness, loss of muscle tone
- Meniere's disease: vertigo, visual phenomena, speech impairment, altered consciousness
- Migraine: aura, loss of consciousness, nausea, photophobia, muscle weakness
- Movement disorder: tics, chorea, tremor
- Syncope: sudden loss of muscle tone and posture, loss of consciousness, vertigo, nausea, muscle spasm
Electroencephalogram (EEG)
EEG is a diagnostic test used to investigate a seizure disorder. It identifies abnormal electrical activity in the brain, provides information about the type of seizure disorder, and locates the area of seizure focus.
Some of the findings on EEG are specific to particular disorders and subtypes of epilepsy. Activity during a seizure can be identified by a pattern on the graph, called epileptiform, which indicates epilepsy. Correlating this type of data with clinical symptoms of seizures often helps make an accurate diagnosis. Additionally, the EEG recording between seizures is often abnormal in patients with epilepsy.
The EEG measures electrical activity in the brain through small electrodes that are placed on the scalp on both sides of the head. If the results are normal, the test is repeated after the patient is subjected to seizure triggers, such as sleep deprivation, flashing light, and hyperventilation. Continuous, 24-72 hour EEG and video monitoring may be performed at home to obtain a record of seizure activity.
Neuroimaging
Magnetic resonance imaging (MRI scan) or computed tomography (CT scan or CAT scan) are performed when a lesion or other structural cause, such as stroke or tumor, is suspected.
Treatment
Antiepileptic drugs (AEDs) can prevent seizure activity by altering neurotransmitter activity in nerve cells, but cannot correct the underlying condition. Approximately 70% of patients successfully control seizures with medication. Nearly 50% of those require two drugs to be seizure free. Because medications interact, the drug regimen must be carefully designed to maximize the effectiveness and to avoid serious complications and side effects.
Treatment with a single drug (monotherapy) is the goal. Seizure management is complicated when patients are given more than one drug. The patient may experience drug interactions, increased side effects, and other adverse reactions.
Compliance is essential. To control seizures, a constant level of medication must be maintained in the body. Antiepileptic drugs should not be discontinued abruptly because of the risk for triggering life-threatening status epilepticus.
Although, antiepileptic drugs may cause abnormal embryo development (i.e., have teratogenetic potential), most women with epilepsy require treatment to prevent seizures during pregnancy. To control seizures and minimize risk to the fetus, women should educate themselves about medication and pregnancy prior to conception.
Surgery
Surgery is an option for a small number of patients whose epilepsy cannot be controlled with medication. A good candidate for surgery has seizures that always begin in the same cerebral location, which can be removed (resected) without creating deficits. Neurosurgeons generally avoid performing surgery in areas of the brain responsible for speech, hearing, and other important functions.
Lobectomy (lesionectomy) -This procedure removes a small part of the brain where seizures originate. It is appropriate only for partial seizures.
Multiple Subpial Transection-When seizures originate in part of the brain that cannot be removed, the surgeon may use this procedure, in which a series of small incisions are made that impede the spread of nerve activity.
Corpus Callosotomy-In this procedure, the surgeon severs the nerve fibers that connect the hemispheres of the brain to each other. This procedure is used to treat uncontrolled generalized tonic-clonic seizures, complex partial seizures with drop attacks, and other generalized seizures. Reduced seizure activity usually continues on one side of the brain.
Hemispherectomy-This procedure is a last resort in children with severe brain damage on one side and seizures that do not respond to medication. It involves removing the entire affected side of the brain. The remaining hemisphere develops language and motor areas for both sides of the body. With intense rehabilitation, many patients will lead functional lives.
Vagus Nerve Stimulator
This small device is implanted near the collarbone and attached to the vagus nerve, which connects the lower part of the brain to the heart, lungs, and gastrointestinal tract. It delivers small bursts of electrical energy to the brain at regular, preprogrammed intervals. In some patients, seizure frequency is reduced. Most patients remain on antiepileptic medication but may be able to reduce the dosage.
Ketogenic Diet
The ketogenic diet is used in children who do not respond to standard therapy or cannot tolerate the side effects produced by antepileptic drugs. The diet is a high-fat, low-carbohydrate diet that fundamentally changes the body's metabolism from using glucose as a primary energy source to using fats. Ketones are a type of lipid, or fat, that provides energy for skeletal muscle, the heart, kidneys, and the brain.
It is most effective in children 10 years of age and younger. Compliance, which is essential for controlling seizures, is difficult to maintain. The regimen often is initiated with fasting period (12-24 hours). Every meal includes exact amounts of fats, proteins, carbohydrates, and beverages, and only those foods listed for the diet can be eaten. Snacking is discouraged and sugars are not allowed. A vitamin and mineral supplement must be given.
The diet should be undertaken only with close medical supervision. Children must be monitored for growth and nutritional deficiencies. Common complications include poor growth and poor weight gain, high cholesterol (hypercholestrolemia), and constipation.
Management
Yoga, acupuncture, aromatherapy, biofeedback, behavior psychotherapy, and meditation may improve the quality of life for patients with epilepsy. Some of these therapies reduce stress, which decreases seizure activity in some patients.
Medications
Medications can be divided into older medications (called first-generation anticonvulsants) and more recently developed medications (second-generation anticonvulsants).
First-Generation Anticonvulsants
Phenytoin (Dilantin®)-This is one of the more commonly used agents and often is considered the first-line drug to treat partial and generalized tonic-clonic (grand mal) seizures and status epilepticus.
Phenytoin is thought to work by suppressing electrical activity in brain nerve cells. It can be given orally or intravenously (IV), and a newer form of the drug, fosphenytoin (Cerebryx®), can be injected into muscle. The oral form has the benefit of once-a-day dosing.
Phenytoin drug levels need to be monitored with liver function testing and a complete blood count (CBC). The therapeutic concentration recommended is between 10-20mg/L. Phenytoin interacts with many other medications, and its level can fluctuate when other drugs are taken.
Side effects associated with its use include:
- Anemia
- Excessive hair growth (hirsuitism/hypertrichosis)
- Imbalance
- Lethargy
- Overgrowth of the gums (gingival hyperplasia)
- Peripheral weakness (neuropathy) with long-term use
Carbamazepine (Tegretol®/Carbatrol®)-This drug is commonly prescribed for the treatment of partial and generalized tonic-clonic (grand mal) seizures. The mechanism by which it works is not well understood. In oral form, it can be taken 2 to 3 times a day; a recent development of the drug in sustained-release form allows for twice-a-day dosing.
Carbamazepine levels must be monitored. The recommended therapeutic level is between 8-12mg/L. Liver function tests and CBC also must be checked routinely. Carbamazepine can affect the levels of a number of other drugs in the body, and its level can fluctuate when other agents are taken.
Side effects include drowsiness, imbalance, nausea, anemia, and low, white blood cell count (neutropenia).
Phenobarbital -This drug is used to treat both partial and generalized seizures. It also is used as part of the protocol after phenytoin use in status epilepticus as well as in neonatal epilepsy. It is available in oral and intravenous forms.
Levels need to be monitored. The recommended therapeutic level is 15-40mg/L. A complete blood analysis also should be routinely conducted. Phenobarbital can cause changes in the metabolism of other drugs through its actions on liver enzymes.
Possible side effects include drowsiness, cognitive impairment, and irritability.
Valproate (Depakote®)-This is prescribed for partial seizures, generalized tonic-clonic (grand mal) seizures, absence (petit mal) seizures, and myoclonic epilepsy. Its mechanism of action is thought to be related to the effect of a brain substance known as GABA (gamma-aminobutyric acid). It is available in oral form and must be taken 2 to 3 times per day for adequate dosing.
Drug levels must be monitored, as well as liver function and blood count. The drug's suggested therapeutic window is 50-100mg/L. Side effects include liver damage (hepatotoxicity), nausea, weight gain, hair loss (alopecia), and tremor.
Second-Generation Anticonvulsants
Topiramate (Topamax®)-This drug is used with other anticonvulsant drugs in the treatment of partial seizures and generalized tonic-clonic seizures in adults and children aged 2 to 16. Its precise mechanism of action is unknown, but its anticonvulsant activity may be due in part to increasing GABA (gamma-aminobutyric acid), a neurotransmitter that inhibits excitation of nerve cells in the brain. It is available in oral form, including sprinkles for children, and is taken twice daily. There are few drug interactions between topiramate and other medications or other anticonvulsants.
Side effects include drowsiness, nausea, dizziness, and coordination problems. Children may have difficulty concentrating and may become aggressive. Acute glaucoma and visual abnormality, a potentially very serious complication, has been reported in a small number of patients. If abnormal visual symptoms occur, patients should notify a physician immediately.
Gabapentin (Neurontin®)-This drug is indicated for the adjunct treatment of partial seizures, with or without secondary generalization. Although it is structurally related to the substance GABA (gamma-aminobutyric acid), it does not interact with GABA receptors in the brain, and its mechanism of action is unknown. It is available in oral form and is taken 3 times daily.
No laboratory monitoring of liver, kidney, or blood (hematologic) function is necessary. Side effects include fatigue, dizziness, and imbalance.
Lamotrigine (Lamictal®)-This drug is used for the adjunct treatment of partial seizures. Its precise mechanism of action is unknown. It is presently available in oral form and is taken twice daily. No laboratory monitoring of drug levels are necessary.
Side effects include headache, nausea, dizziness, and skin rash. The appearance of the potentially life-threatening skin rash, particularly for patients who also are taking valproate (Depakote®), should be reported immediately to a physician.
Tiagabine (Gabitril®)-This drug is indicated for adjunct therapy in adults with partial seizures. Its mechanism of action may be related to its effect on the brain substance GABA (gamma-aminobutyric acid). It is available in oral form and should be given in divided doses 2 to 4 times daily.
No laboratory monitoring of tiagabine levels are necessary. Its metabolism may be altered when taken with other anticonvulsants. Side effects include dizziness and somnolence.
Levetiracetam (Keppra®)-This drug is approved for use in adults and children 4 years of age and older as adjunct therapy for the treatment of partial seizure disorders. It is available in tablet form and as an oral solution for patients who prefer a liquid or cannot swallow tablets. Side effects can include fatigue, imbalance, and behavioral changes, which often dissipate after the first month of treatment.
Oxcarbazepine (Trileptal®)-This drug is indicated for monotherapy (used alone) and adjunct therapy (in addition to other medications) in adults who have partial seizures and as adjunct therapy in children aged 4 and older who have partial seizures. When used as monotherapy, Trileptal causes very few of the side effects associated with other AEDs.
Side effects are usually mild or moderate and include the following:
- Abdominal pain, nausea, vomiting
- Dizziness
- Double vision
- Drowsiness, fatigue
- Loss of coordination, abnormal gait
Zonisamide (Zonegram®)-This drug is approved for use in adults as adjunct therapy for partial seizures. It has however, been used fairly extensively in other countries for use in other seizure types including generalized seizures, myoclonic seizures, and absence seizures. Side effects can include dizziness, imbalance, and fatigue. Patients who are allergic to sulfonamide drugs should not use zonisamide because it is a derivative of this class of drug.
Ethosuximide (Zarontin®)-This agent is used to treat absence (petit mal) seizures. It is thought to work by suppressing brain cell activity that is associated with lapses of consciousness. It is given orally and is available as a tablet or flavored syrup.
Ethosuximide levels need to be monitored to ensure that the therapeutic concentration of 40 to 100 mcg/mL is maintained. Complete blood count (CBC), urinalysis, and liver function tests also should be performed routinely to monitor for possible adverse effects.
Potential side effects produced by ethosuximide include the following:
- Gastrointestinal-nausea and vomiting, abdominal pain, cramps, diarrhea, weight loss
- Genitourinary-vaginal bleeding, blood in urine (microscopic hematuria)
- Hematological-bone marrow suppression
- Integumentary-excessive hair growth (hirsutism ), skin rash, systemic lupus erythematous (SLE)
- Neurological-headache, dizziness, sleep disturbances, aggression, incoordination, fatigue, inability to concentrate
Primidone (Mysoline®)-This drug is a barbiturate that contains phenobarbitol. It is used to control generalized tonic-clonic (grand mal) seizures and partial seizures and is used in adults and children over 8 years old.
The effective concentration of primidone in the body is 5-12 mcg/mL. This is achieved with 250 mg tablets taken 3 to 4 times daily. The dosage may be increased, but should not exceed 500 mg taken 4 times daily.
Potential side effects include:
- Blurred vision
- Fatigue
- Incoordination
- Nausea and vomiting
- Sexual impotence (erectile dysfunction)
- Vertigo
- Weight loss
Primidone is not known to interact with other drugs. It is present in breast milk and is associated with neonatal hemorrhage and coagulation defects similar to vitamin K deficiency. Patients hypersensitive to phenobarbital should not take primidone.
Pregabalin (Lyrica®)-This drug is approved for use in adults as adjunct therapy for partial onset seizures. Lyrica, which is also used to treat diabetic peripheral neuropathy and postherpetic neuralgia, can be taken 2 or 3 times a day.
Side effects include the following:
- Blurred vision
- Difficulty concentrating
- Dizziness
- Dry mouth
- Peripheral edema (swelling)
- Somnolence (excessive sleepiness)
Prognosis
When a patient has been seizure-free for several consecutive years, it may be possible to discontinue medication, depending on the patient's age and the type of epilepsy. This is only done under the supervision of a physician. As many as three-quarters of adults who have been free of seizures for 3 years remain seizure free after discontinuing drug therapy. More than one-half of children can stop medication without developing seizures.
The prognosis is not as encouraging for those who take more than one antiepileptic drug, have a family history of epilepsy, experience partial seizures, or continue to have abnormal EEGs while on medication.
First Aid
A person experiencing a generalized tonic-clonic seizure or a simple partial seizure that has become convulsive requires first aid. Call an ambulance if the seizure lasts longer than 5 minutes, one seizure follows another without the person regaining consciousness, or the person is seriously injured.
The goals of first aid are to
- prevent injury,
- maintain an open airway,
- provide reassurance to the patient and bystanders,
- recognize an emergency condition, and
- know when to call for help.
Guidelines for helping someone having a seizure:
- Help the person lie down as soon as possible.
- Look for a medical alert bracelet, pendant, or wallet card.
- If a medical alert ID or other documentation indicating that the person has epilepsy cannot be located, call an ambulance.
- If the person is pregnant or diabetic, call an ambulance.
- Turn the person onto one side and put a soft object (e.g., pillow, sweater, jacket) under their head. Lying on the side allows secretions to drain from the mouth; prevents the inhalation of secretions; and allows the tongue to fall forward, keeping the airway open. Do not try to hold the tongue.
- Do not put anything into the person's mouth. During the initial phase of a generalized tonic-clonic seizure, the jaw muscles tighten and it is impossible to open the mouth. Forcing an object into the mouth can damage the jaw or teeth.
- Loosen ties and collars.
- Remove harmful objects from the immediate area.
- Do not restrain the person in any way. Restraining while the person is rigid or having convulsions may cause broken bones or bruising. Restraining someone having a complex partial seizure may provoke them into aggressive behavior.
- Remain with the person until they are completely aware of who they are and their environment, stay calm, and offer reassurance to the person and to bystanders.
Someone having a complex partial seizure may wander or look confused but does not require first aid. It is helpful to calmly and gently guide the person away from harmful objects or situations. Do not attempt to restrain the person.
First aid is not necessary for someone having an absence seizure . They experience a temporary lapse in alertness and need monitoring to ensure their safety.