Seizures

Most people are familiar with a spectrum disorder called epilepsy, which results in various types of seizures that vary in severity. While any seizure is cause for concern, having a seizure does not by itself mean a person has epilepsy. First seizures, febrile seizures, nonepileptic events and eclampsia (a life-threatening condition that can occur in pregnant women) are examples of conditions involving seizures that may not be associated with epilepsy. Regardless of the type of seizure, it’s important to inform your doctor when one occurs.

Seizures are divided into two major categories: focal seizures and generalized seizures. However, there are many different types of seizures in each of these categories. In fact, doctors have described more than 30 types.

Many people have a single seizure at some point in their lives, and it can be provoked or unprovoked, meaning that they can occur with or without any obvious triggering factor. Unless the person has suffered brain damage or there is a family history of epilepsy or other neurological abnormalities, the majority of single seizures usually are not followed by additional seizures. Medical disorders that can provoke a seizure include low blood sugar, very high blood sugar in diabetics, disturbances in salt levels in the blood (sodium, calcium, magnesium), eclampsia during or after pregnancy, impaired function of the kidneys, or impaired function of the liver. Sleep deprivation, missing meals or stress may serve as seizure triggers in susceptible people.

Many people with a first seizure will never have a second seizure, and physicians often counsel against starting antiseizure drugs at this point. In some cases where additional epilepsy risk factors are present, drug treatment after the first seizure may help prevent future seizures. Evidence suggests that it may be beneficial to begin antiseizure medication once a person has had a second unprovoked seizure, as the chance of future seizures increases significantly after this occurs. A person with a preexisting brain problem—for example, a prior stroke or traumatic brain injury—will have a higher risk of experiencing a second seizure. In general, the decision to start antiseizure medication is based on the doctor's assessment of many factors that influence how likely it is that another seizure will occur in that person.

In one study that followed individuals for an average of eight years, 33 percent of people had a second seizure within four years after an initial seizure. People who did not have a second seizure within that time remained seizure-free for the rest of the study. For people who did have a second seizure, the risk of a third seizure was about 73 percent by the end of four years. Among those with a third unprovoked seizure, the risk of a fourth was 76 percent.

Not infrequently, a child will have a seizure during the course of an illness with a high fever. These seizures are called febrile seizures. Antiseizure medications following a febrile seizure are generally not warranted unless certain other conditions are present: a family history of epilepsy, signs of nervous system impairment prior to the seizure, or a relatively prolonged or complicated seizure. The risk of subsequent non-febrile seizures is low unless one of these factors is present.

Febrile seizures are seizures or convulsions that occur in young children. They are triggered by fever typically above 101 degrees Fahrenheit (38.3 degrees Celsius). Seizures may happen during illnesses such as a cold, the flu or an ear infection. In some cases, a child may not have a fever at the time of the seizure but will develop one a few hours later.

Having a febrile seizure does not mean a child has epilepsy. Epilepsy involves repeat seizures that are not triggered by fever.  

Results from a study funded by the National Institute of Neurological Disorders and Stroke (NINDS) suggested that certain findings using diagnostic imaging of the hippocampus may help identify which children with prolonged febrile seizures are subsequently at increased risk of developing epilepsy.

Researchers also have identified several different genes that influence the risks associated with febrile seizures in certain families. Studying these genes may lead to new understandings of how febrile seizures occur and perhaps point to ways of preventing them.

Focal seizures originate in just one part of the brain. About 60 percent of people with epilepsy have focal seizures. These seizures are frequently described by the area of the brain in which they originate. Many people are diagnosed with focal frontal lobe or medial temporal lobe seizures.

In some focal seizures, the person remains conscious but may experience motor, sensory or psychic feelings (for example, intense déjà vu or memories) or sensations that can take many forms. The person may experience sudden and unexplainable feelings of joy, anger, sadness or nausea. He or she also may hear, smell, taste, see or feel things that are not real and may have movements of just one part of the body—for example, just one hand.

In other focal seizures, the person has a change in consciousness, which can produce a dreamlike experience. The person may display strange, repetitious behaviors such as blinks, twitches and mouth movements (often like chewing or swallowing, or even walking in a circle). These repetitive movements are called automatisms. More complicated actions, which may seem purposeful, can also occur involuntarily. Individuals may also continue activities they started before the seizure began, such as washing dishes in a repetitive, unproductive fashion. These seizures usually last just a minute or two.

Some people with focal seizures may experience auras—unusual sensations that warn of an impending seizure. Auras are usually focal seizures without interruption of awareness (e.g., déjà vu or an unusual abdominal sensation), but some people experience a true warning before an actual seizure. An individual's symptoms, and the progression of those symptoms, tend to be similar every time. Other people with epilepsy report experiencing a prodrome, a feeling that a seizure is imminent lasting hours or days.

The symptoms of focal seizures can easily be confused with other disorders. The strange behavior and sensations caused by focal seizures also can be mistaken for symptoms of narcolepsy, fainting or even mental illness. Several tests and careful monitoring may be needed to make the distinction between epilepsy and these other disorders.

Generalized seizures are a result of abnormal neuronal activity that rapidly emerges on both sides of the brain. These seizures may cause loss of consciousness, falls or massive muscle contractions. The types of generalized seizures and their effects include:

• Absence seizures, which may cause the person to appear to be staring into space with or without slight twitching of the muscles.
• Tonic seizures, which cause stiffening of muscles of the body, generally those in the back, legs and arms.
• Clonic seizures, which cause repeated jerking movements of muscles on both sides of the body.
• Myoclonic seizures, which cause jerks or twitches of the upper body, arms or legs.
• Atonic seizures, which cause a loss of normal muscle tone, often lead the affected person to fall down or drop the head involuntarily.
• Tonic-clonic seizures cause a combination of symptoms, including stiffening of the body and repeated jerks of the arms and/or legs as well as loss of consciousness.
• Secondary generalized seizures.

Not all seizures can be easily defined as either focal or generalized. Some people have seizures that begin as focal seizures but then spread to the entire brain. Other people may have both types of seizures but with no clear pattern.

Some people recover immediately after a seizure, while others may take minutes to hours to feel as they did before the seizure. During this time, they may feel tired, sleepy, weak or confused.

Following focal seizures or seizures that started from a focus, there may be local symptoms related to the function of that focus. Certain characteristics of the post-seizure (or post-ictal) state may help locate the region of the brain where the seizure occurred. A classic example is called Todd's paralysis, a temporary weakness in the part of the body that was affected depending on where in the brain the focal seizure occurred. If the focus is in the temporal lobe, post-ictal symptoms may include language or behavioral disturbances, even psychosis. After a seizure, some people may experience headache or pain in muscles that contracted.

Non-epileptic events may be referred to as psychogenic non-epileptic seizures (PNES). PNES do not respond to antiseizure drugs; instead, PNES are often treated by cognitive behavioral therapy to decrease stress and improve self-awareness.

A history of traumatic events is among the known risk factors for PNES. People with PNES should be evaluated for underlying psychiatric illness and treated appropriately. Two studies together showed a reduction in seizures and fewer coexisting symptoms following treatment with cognitive behavioral therapy. Some people with epilepsy have psychogenic seizures in addition to their epileptic seizures.

Other nonepileptic events may be caused by:

• Narcolepsy (sudden attacks of sleep)
• Tourette syndrome (repetitive involuntary movements called tics)
• Cardiac arrhythmia (irregular heartbeat)
• Other medical conditions with symptoms that resemble seizures

Because symptoms of these disorders can look very much like epileptic seizures, they are often mistaken for epilepsy.

In some focal seizures, the person remains conscious but may experience motor, sensory or psychic feelings (for example, intense déjà vu or memories) or sensations that can take many forms. The person may experience sudden and unexplainable feelings of joy, anger, sadness or nausea. He or she also may hear, smell, taste, see or feel things that are not real and may have movements of just one part of the body—for example, just one hand.

In other focal seizures, the person has a change in consciousness, which can produce a dreamlike experience. The person may display strange, repetitious behaviors such as blinks, twitches and mouth movements (often like chewing or swallowing, or even walking in a circle). These repetitive movements are called automatisms. More complicated actions, which may seem purposeful, can also occur involuntarily. Individuals may also continue activities they started before the seizure began, such as washing dishes in a repetitive, unproductive fashion. These seizures usually last just a minute or two.

Some people with focal seizures may experience auras—unusual sensations that warn of an impending seizure. Auras are usually focal seizures without interruption of awareness (e.g., déjà vu or an unusual abdominal sensation), but some people experience a true warning before an actual seizure. An individual's symptoms, and the progression of those symptoms, tend to be similar every time. Other people with epilepsy report experiencing a prodrome, a feeling that a seizure is imminent lasting hours or days.

The symptoms of focal seizures can easily be confused with other disorders. The strange behavior and sensations caused by focal seizures also can be mistaken for symptoms of narcolepsy, fainting or even mental illness. Several tests and careful monitoring may be needed to make the distinction between epilepsy and these other disorders.

Generalized seizures are a result of abnormal neuronal activity that rapidly emerges on both sides of the brain. These seizures may cause loss of consciousness, falls or massive muscle contractions. The types of generalized seizures and their effects include:

• Absence seizures, which may cause the person to appear to be staring into space with or without slight twitching of the muscles.
• Tonic seizures, which cause stiffening of muscles of the body, generally those in the back, legs and arms.
• Clonic seizures, which cause repeated jerking movements of muscles on both sides of the body.
• Myoclonic seizures, which cause jerks or twitches of the upper body, arms or legs.
• Atonic seizures, which cause a loss of normal muscle tone, which often leads the affected person to fall down or drop the head involuntarily.
• Tonic-clonic seizures, which cause a combination of symptoms, including stiffening of the body and repeated jerks of the arms and/or legs as well as loss of consciousness.
• Secondary generalized seizures.

Not all seizures can be easily defined as either focal or generalized. Some people have seizures that begin as focal seizures but then spread to the entire brain. Other people may have both types of seizures but with no clear pattern.

Some people recover immediately after a seizure, while others may take minutes to hours to feel as they did before the seizure. During this time, they may feel tired, sleepy, weak or confused.

Following focal seizures or seizures that started from a focus, there may be local symptoms related to the function of that focus. Certain characteristics of the post-seizure state may help locate the region of the brain where the seizure occurred. A classic example is called Todd's paralysis, a temporary weakness in the part of the body that was affected depending on where in the brain the focal seizure occurred. If the focus is in the temporal lobe, post-ictal symptoms may include language or behavioral disturbances, even psychosis. After a seizure, some people may experience headache or pain in muscles that contracted.

Having a febrile seizure does not mean a child has epilepsy. Epilepsy involves repeat seizures that are not triggered by fever.  

Symptoms may include:

• Loss of consciousness or passing out
• Uncontrollable shaking
• Eye rolling
• Rigid (stiff) limbs

Less commonly, a child can become rigid or have twitches in only part of the body.

Most febrile seizures last a minute or two. Yet some may only last a few seconds and others may last for more than 15 minutes.

Febrile seizures that last less than 15 minutes do not cause any long-term health problems. However, if another one happens, it is more likely to be prolonged or longer than 15 minutes. A first febrile seizure that is prolonged does not boost the risk of having more. Even prolonged seizures are generally harmless on their own, but they do carry an increased risk of developing epilepsy.

Dietary approaches and other treatments may be more appropriate depending on the age of the individual and the type of epilepsy. A high-fat, very low-carbohydrate ketogenic diet is often used to treat medication-resistant epilepsies. The diet induces a state known as ketosis, which means that the body shifts to breaking down fats instead of carbohydrates to survive. A ketogenic diet effectively reduces seizures for some people, especially children with certain forms of epilepsy. Studies have shown that more than 50 percent of people who try the ketogenic diet have a greater than 50 percent improvement in seizure control and 10 percent experience seizure freedom. Some children are able to discontinue the ketogenic diet after several years and remain seizure-free, but this is done with strict supervision and monitoring by a physician.

The ketogenic diet is not easy to maintain, as it requires strict adherence to a limited range of foods. Possible side effects include impaired growth due to nutritional deficiency and a buildup of uric acid in the blood, which can lead to kidney stones.

Researchers are looking at modified versions of and alternatives to the ketogenic diet. For example, studies show promising results for a modified Atkins diet and for a low-glycemic-index treatment, both of which are less restrictive and easier to follow than the ketogenic diet, but well-controlled randomized controlled trials have yet to assess these approaches.

Evaluation for surgery is generally recommended only after focal seizures persist despite the person having tried at least two appropriately chosen and well-tolerated medications, or if there is an identifiable brain lesion believed to cause the seizures. When someone is considered to be a good candidate for surgery, experts generally agree that it should be performed as early as possible.

Surgical evaluation takes into account the:

• Seizure type
• Brain region involved
• Importance of the area of the brain where seizures originate (the focus) for everyday behavior

While surgery can significantly reduce or even halt seizures for many people, any kind of surgery involves some level of risk. Surgery for epilepsy does not always successfully reduce seizures, and it can result in cognitive or personality changes as well as physical disability, even in people who are excellent candidates for it. Nonetheless, when medications fail, several studies have shown that surgery is much more likely to make someone seizure-free compared to attempts to use other medications. Anyone thinking about surgery for epilepsy should be assessed at an epilepsy center experienced in surgical techniques and should discuss with the epilepsy specialists the balance between the risks of surgery and desire to become seizure-free.

Even when surgery completely ends a person's seizures, it is important to continue taking antiseizure medication for some time. Doctors generally recommend continuing medication for at least two years after a successful operation to avoid recurrence of seizures.

Electrical stimulation of the brain remains a therapeutic strategy of interest for people with medication-resistant forms of seizures who are not candidates for surgery. The FDA-approved vagus nerve stimulator is surgically implanted under the skin of the chest and is attached to the vagus nerve in the lower neck. The device delivers short bursts of electrical energy to the brain via the vagus nerve. On average, this stimulation reduces seizures by about 20 to 40 percent. Individuals usually cannot stop taking antiseizure medication because of the stimulator, but they often experience fewer seizures and may be able to reduce the dosage of their medication.

Responsive stimulation involves the use of an implanted device that analyzes brain activity patterns to detect a forthcoming seizure. Once detected, the device administers an intervention, such as electrical stimulation or a fast-acting drug to prevent the seizure from occurring. These devices are also known as closed-loop systems. NeuroPace, one of the first responsive stimulation, closed-loop devices, is available for adults with refractory epilepsy (hard-to-treat epilepsy that does not respond well to trials of at least two medicines).

Experimental devices that are not approved by the FDA for use in the U.S. (as of March 2015) include the following:

• Deep brain stimulation using mild electrical impulses has been tried as a treatment for seizures in several different brain regions. It involves surgically implanting an electrode connected to an implanted pulse generator (similar to a heart pacemaker) to deliver electrical stimulation to specific areas in the brain to regulate electrical signals in neural circuits. Stimulation of an area called the anterior thalamic nucleus has been particularly helpful in providing at least partial relief from seizures in people who had medication-resistant forms of the disorder.
• A report on trigeminal nerve stimulation (using electrical signals to stimulate parts of the trigeminal nerve and affected brain regions) showed efficacy rates similar to those for vagal nerve stimulation, with responder rates hovering around 50 percent. (A responder is defined as someone having greater than a 50 percent reduction in seizure frequency.) Freedom from seizures, although reported, remains rare for both methods. A trigeminal nerve stimulation device is available for use in Europe, but it is not yet approved in the U.S.
• Transcutaneous magnetic stimulation involves a device being placed outside the head to produce a magnetic field to induce an electrical current in nearby areas of the brain. 

Parents and caregivers of children who have experienced a febrile seizure should remain calm, take first aid measures, and carefully watch the child. During a febrile seizure, parents and caregivers should:

• Note the start time of the seizure. If it lasts longer than five minutes, call an ambulance. The child should be taken right away to the nearest medical facility.
• Call an ambulance if the seizure is less than five minutes but the child does not seem to be recovering quickly.
• Gradually place the child on a protected surface such as the floor to prevent injury. Do not restrain or hold a child during a convulsion.
• Put the child on his or her side or stomach to prevent choking. When possible, gently remove any objects from the child's mouth. Nothing should ever be placed in the child's mouth during a seizure. These objects can block the airway and make it hard to breathe.
• Seek immediate medical attention if this is the child's first febrile seizure. Once it is over, take the child to the doctor to check for the cause of the fever. This is especially urgent if the child shows symptoms of meningitis, an infection over the brain surface, which can include stiff neck, extreme lethargy or a lot of vomiting.

Drugs that lower fevers such as acetaminophen or ibuprofen may provide comfort, yet studies show that treating a fever does not lower the risk of febrile seizure. Healthcare providers may recommend other medications to control seizures if needed.