brain, spinal cord, and nerve disorders
Seizure Disorders
Symptoms of Seizure Disorders
 (unusual sensations) describes how a person feels before a seizure starts. Usually, it is part of a Focal-onset seizures that is just starting. An aura may include any of the following: Abnormal smells or tastes Butterflies in the stomach Feeling as if something has been experienced before even though it has not (called déjà vu) or the opposite feeling—something seems unfamiliar even though it is familiar in some way (called jamais vu) An intense feeling that a seizure is about to begin Almost all seizures are relatively brief, lasting from a few seconds to a few minutes. Most seizures last 1 to 2 minutes. Occasionally, seizures recur repeatedly, as occurs in status epilepticus. Most people who have a seizure disorder look and behave normally between seizures. Symptoms of seizures vary depending on Brain Dysfunction by Location by the abnormal electrical discharge, as in the following: An intensely pleasant or unpleasant taste if the part of the cerebrum called the insula is affected Visual hallucinations (seeing unformed images) if the occipital lobe is affected Inability to speak if the area that controls speech (located in the frontal lobe) is affected A convulsion (jerking and spasms of muscles throughout the body) if large areas on both sides of the brain are affected Seizures may be classified as Motor: Involving abnormal muscle contractions (such as jerking of a limb or convulsions) Nonmotor: Not involving abnormal muscle contractions Other possible symptoms include numbness or tingling in a specific body part, brief episodes of unresponsiveness, loss of consciousness, and confusion. People may vomit if they lose consciousness. People may lose control of their muscles, bladder, or bowels. Some people bite their tongue. Symptoms also vary depending on whether the seizure is Focal-onset (the seizure begins in one side of the brain) Generalized-onset (the seizure begins in both sides of the brain) There are several types of focal and generalized seizures. Most people have only one type of seizure. Others have two or more types. Some types of seizures may be focal, then become generalized. In focal-onset seizures, the seizures begin in one side of the brain. Focal-onset seizures include the following types: Automatisms (coordinated, purposeless, repetitive motor activity) Atonic (involving loss of muscle tone) Clonic (involving rhythmic jerking of muscles) Epileptic spasms (involving bending and straightening the arms and bending the upper body forward) in children Hyperkinetic (involving moving the legs as if pedaling a bicycle or thrashing) Myoclonic (involving sudden, lightning-like jerking of muscles) Tonic (involving stiffening of muscles of one limb or one side of the body) Some people who have a focal-onset seizure recover fully. In others, the abnormal electrical discharge spreads to adjacent areas and to the other side of the brain, resulting in a generalized seizure. Generalized seizures that result from focal seizures are called focal-to-bilateral seizures. That is, they start in one side of the brain and spread to both sides. Focal-onset seizures are classified based on whether the person is aware during the seizure: Awareness is maintained (called focal aware seizures). Awareness is impaired (called focal impaired-awareness seizures). Awareness refers to knowledge of self and environment. If awareness is impaired during any part of the seizure, the seizure is considered a focal impaired-awareness seizure. Doctors determine whether people remained aware during a seizure by asking them or, if a seizure is occurring, seeing whether they respond when spoken to. Infocal aware seizures,abnormal electrical discharges begin in a small area of the brain and remain confined to that area. Because only a small area of the brain is affected, symptoms are related to the function controlled by that area. For example, if the small area of the brain that controls the right arm’s movements (in the left frontal lobe) is affected, the right arm may involuntarily be lifted up and jerk, and the head may turn toward the lifted arm. People are completely conscious and aware of the surroundings. A focal aware seizure may progress to a focal impaired-awareness seizure. Jacksonian seizuresare a type of focal aware seizures. Symptoms start in one hand or foot, then move up the limb as the electrical activity spreads in the brain. People are completely aware of what is occurring during the seizure. Other focal aware seizures affect the face, then spread to an arm or sometimes a leg. Epilepsia partialis continuais rare. In this type of seizure, focal seizures occur every few seconds or minutes for days to years at a time. They typically affect an arm, a hand, one side of the face, or one side of the body. People with epilepsia partialis continua remain aware. These seizures usually result from In adults: Brain damage (such as scarring due to a Overview of Stroke ) in one area of the brain In children: Inflammation of the brain (as occurs in Encephalitis and Infocal impaired-awareness seizures,abnormal electrical discharges begin in a small area of the temporal lobe or frontal lobe and quickly spread to other nearby areas. The seizures usually begin with an aura, which lasts 1 to 2 minutes. During the aura, people start to lose touch with the surroundings. During focal impaired-awareness seizures, awareness becomes impaired, but people do not become unconscious. People may do the following: Stare Chew or smack the lips involuntarily Move the hands, arms, and legs in strange, purposeless ways Utter meaningless sounds Not understand what other people are saying Resist help Some people can converse, but their conversation lacks spontaneity, and the content is somewhat sparse. They may be confused and disoriented. This state may last for several minutes. Occasionally, people lash out if they are restrained. In generalized-onset seizures, the seizure begins in both sides of the brain. Most generalized-onset seizures impair awareness. They often cause loss of consciousness and abnormal movements, usually immediately. Loss of consciousness may be brief or last a long time. Generalized-onset seizures include the following types: Tonic-clonic seizures (formerly, called grand mal seizures) Clonic seizures (involving sustained rhythmic jerking of muscles after muscles stiffen) Tonic seizures (involving stiffening of muscles in all limbs) Atonic seizures (involving loss of muscle tone) Myoclonic seizures (involving rhythmic jerking of muscles not preceded by stiffening of muscles) Myoclonic-tonic-clonic seizures (involving jerking of muscles followed by muscle stiffening and repeated jerking of muscles), including juvenile myoclonic epilepsy Myoclonic-atonic seizures (involving jerking of muscles, followed by loss of muscle tone) Epileptic (infantile) spasms Absence seizures Most types of generalized seizures (such as tonic-clonic seizures) involve abnormal muscle contractions. Those that do not are called absence seizures. Generalized-onset seizuresbegin with abnormal discharges in a deep, central part of the brain and spread simultaneously to both sides of the brain. There is no aura. The seizure typically begins with an outcry. People then become unaware or lose consciousness. During generalized-onset seizures, particularly generalized tonic-clonic seizures, people may do the following: Have severe muscle spasms and jerking throughout the body as muscles rapidly and repeatedly contract and relax Fall down Clench their teeth Bite their tongue (often occurs) Drool or froth at the mouth Lose control of the bladder and/or bowels The seizures usually last 1 to 2 minutes. Afterward, some people have a headache, are temporarily confused, and feel extremely tired. These symptoms may last from minutes to hours. Most people do not remember what happened during the seizure. Ingeneralized tonic-clonic seizures,muscles contract (the tonic part), then rapidly alternate between contracting and relaxing (the clonic part). These seizures may be Generalized-onset (starting in both sides of the brain) Focal to bilateral (starting in one side of the brain and spreading to both sides) In both types, consciousness is temporarily lost and a convulsion occurs when the abnormal discharges spread to both sides of the brain. Focal-to-bilateral tonic-clonic (grand mal) seizuresusually begin with an abnormal electrical discharge in a small area of one side of the brain, resulting in a focal aware or focal impaired-awareness seizure. The discharge then quickly spreads to both sides of the brain, causing the entire brain to malfunction. Symptoms are similar to those of generalized-onset seizures. Atonic seizuresoccur primarily in children. They are characterized by a brief but complete loss of muscle tone and consciousness. They cause children to fall to the ground, sometimes resulting in injury. Inclonic seizures,the limbs on both sides of the body and often head, neck, face, and trunk jerk rhythmically throughout the seizure. Clonic seizures usually occur in infants. They are much less common than tonic-clonic seizures. Tonic seizuresoccur commonly during sleep, usually in children. Muscle tone increases abruptly or gradually, causing muscles to stiffen. The limbs and neck are often affected. Tonic seizures typically last only 10 to 15 seconds but can cause people, if standing, to fall to the ground. Most people do not lose consciousness. If seizures last longer, muscles may jerk a few times as the seizure ends. Atypical absence seizures (see below), atonic seizures, and tonic seizures usually occur as part of a severe form of epilepsy called Lennox-Gastaut syndrome, which begins before children are 4 years old. Myoclonic seizuresare characterized by quick jerks of one or several limbs or the trunk. The seizures are brief and do not cause loss of consciousness, but they may occur repetitively and may progress to a tonic-clonic seizure with loss of consciousness. Inmyoclonic-atonic seizures,the limbs or trunk jerks briefly, then goes limp (drop attack). Seizures usually begin between the ages of 6 months to 6 years. Before the first myoclonic-atonic seizure, two thirds of children have febrile seizures and generalized-onset convulsive seizures. Development and mental processes are typically normal, but during or after the seizure, development and thinking may be impaired. Juvenile myoclonic epilepsytypically begins during adolescence. Typically, seizures begin with quick jerks of both arms. About 90% of these seizures are followed by generalized tonic-clonic seizures. Some people also have absence seizures. The seizures often occur when people awaken in the morning, especially if they are sleep-deprived. Drinking alcohol also makes these seizures more likely. Absence seizuresdo not involve abnormal muscle contraction. They may be classified as Typical (formerly called petit mal) Atypical Typical absence seizuresusually begin in childhood, usually between the ages of 5 and 15 years, and do not continue into adulthood. However, adults occasionally have typical absence seizures. Unlike tonic-clonic seizures, absence seizures do not cause convulsions or other dramatic symptoms. People do not fall down, collapse, or move jerkily. Instead, they have episodes of staring with fluttering eyelids and sometimes twitching facial muscles. They typically lose consciousness, becoming completely unaware of their surroundings. These episodes last 10 to 30 seconds. People abruptly stop what they are doing and resume it just as abruptly. They experience no after-effects and do not know that a seizure has occurred. Without treatment, many people have several seizures a day. Seizures often occur when people are sitting quietly. Seizures rarely occur during exercise. Hyperventilation can trigger a seizure. Atypical absence seizuresdiffer from typical absence seizures as follows: They are less common. They last longer. Jerking and other movements are more pronounced. People are more aware of their surroundings. Most people with atypical absence seizures have neurologic abnormalities or developmental delays. Atypical absence seizures usually continue into adulthood. Dravet syndrome (severe myoclonic epilepsy of infancy) develops during early childhood. It has focal and generalized characteristics. During the first year of life, focal seizures are typically triggered by fever. At about age 2 years, children tend to have generalized myoclonic seizures. In these seizures, the trunk or one or several limbs jerk. Children with Dravet syndrome may also develop atypical absence, clonic, atonic, or tonic-clonic seizures. During the second year of life, children no longer develop as expected and may lose the developmental skills they have achieved. Children have difficulty thinking and learning and lack coordination and balance. In about 70 to 80% of children with Dravet syndrome, the cause is an abnormal gene known to cause seizures. Convulsive status epilepticusis the most serious seizure disorder and is considered a medical emergency because the seizure does not stop. Electrical discharges occur throughout the brain, causing a generalized tonic-clonic seizure. Convulsive status epilepticus is diagnosed when one or both of the following occur: A seizure lasts more than 5 minutes People do not completely regain consciousness between two or more seizures People have convulsions with intense muscle contractions and often cannot breathe adequately. Body temperature increases. Without rapid treatment, the heart and brain can become overtaxed and permanently damaged, sometimes resulting in death. Generalized convulsive status epilepticus has many causes, including injuring the head and abruptly stopping an antiseizure medication. Nonconvulsive status epilepticus,another type of status epilepticus, does not cause convulsions. The seizures last 10 minutes or more. During the seizure, mental processes (including awareness) and/or behavior are affected. People may appear confused or spaced out. They may be unable to speak and may behave irrationally. Having nonconvulsive status epilepticus increases the risk of developing convulsive status epilepticus. This type of seizure requires prompt diagnosis and treatment. When a seizure stops, people may have a headache, sore muscles, unusual sensations, confusion, and profound fatigue. These after-effects are called the postictal state. In some people, one side of the body is weak after a seizure, and the weakness lasts longer than the seizure (a disorder called Todd paralysis). Most people do not remember what happened during the seizure (a condition called postictal amnesia). Seizures may have serious consequences. Intense, rapid muscle contractions can cause injuries, including broken bones. Sudden loss of consciousness can cause serious injury due to falls and accidents. People may have numerous seizures without incurring serious brain damage. However, seizures that recur and cause convulsions may eventually impair intelligence. If seizures are not well-controlled, people may be unable to get a driver’s license. They may have difficulty keeping a job or getting insurance. They may be socially stigmatized. As a result, their quality of life may be substantially reduced. If seizures are not completely controlled, people are two to three times more likely to die than those who do not have seizures. A few people die suddenly for no apparent reason—a complication called sudden unexpected death in epilepsy. This disorder usually occurs at night or during sleep. Risk is highest for people who have frequent seizures, especially generalized tonic-clonic seizures. Many types of seizures do not cause convulsions and loss of consciousness. 