Seizures and Epilepsy
Epilepsy is one of the most common neurological conditions. It affects about one percent of the population. Some people are born with epilepsy, either as a result of an inherited condition or as a result of brain injury that happens before birth. However, many patients develop epilepsy after birth. There is a common belief that epilepsy always starts during childhood, however, the truth is that epilepsy can start at any age and many patients do not have their first seizure until later in life. With advances in medicine, we are now able to provide effective treatment to prevent seizures, and most patients with epilepsy can lead normal and productive lives.This page provides a brief overview of seizures and epilepsy. For more detailed information, please visit the websites of the International League Against Epilepsy and the Epilepsy Foundation, in addition to www.epilepsy.com. For information about remodeling your home for accessibility, you may visit Expertise/Home website.
What is Epilepsy?
Epilepsy is a disease of the brain where a patient has a tendency to have recurrent seizures. Epilepsy can have many different causes. For example, a patient might be born with epilepsy and start having seizures soon after birth, and another patient might develop epilepsy after severe trauma to the head.
What is a Seizure?
A seizure is a surge of electricity in the brain. Normally, the brain fires electricity constantly. In fact, brain cells can be viewed as electrical wires that transmit electricity and form very complex electrical networks. However, the electricity in the brain is well balanced. When something disrupts the normal balance, a surge of electricity occurs, called a seizure. This surge of electricity frequently causes changes in the patient's behavior, however, sometimes seizures are silent and patients are unaware that they are happening. Seizures usually last between thirty seconds and two minutes, but some seizures are shorter, lasting less than 10 seconds or longer, lasting over five minutes. Occasionally, seizures can be very prolonged, lasting over half an hour. In this case, we call them status epilepticus. The symptoms experienced by a patient during a seizure depend on the part of the brain involved. For example, if a seizure affects the part of the brain that controls eye sight (occipital cortex), the patient might experience visual hallucinations and if the seizure affects the part of the brain that controls movement, the patient might experience uncontrollable movements of the face, arm or leg and so forth.
Types of Seizures
There are many different kinds of seizures. The easiest way to classify seizures is based on the pattern of electrical activity in the brain. Seizures that start everywhere in the brain all at once are called generalized and seizures that start in a specific point in the brain are called focal.
Generalized seizures are seizures that start all over the brain all at once. There are several types of generalized seizures, and patients who have generalized seizures frequently have more than one type:
Tonic Seizures consist of a sudden contraction of the muscles, which usually affects the whole body, but sometimes only affects one part of the body. If the patient is standing and the tonic seizure affects the legs, then the patient might fall.
Atonic Seizures consist of a sudden loss of muscle tone, which can affect any part of the body. For example, if an atonic seizure affects the neck muscles, the head will drop and if it affects the muscles of the trunk and legs, the patient might fall.
Myoclonic Seizures consist of sudden rapid jerk of the arms, head or legs. Occasionally, myoclonic clonic seizures can be very severe leading to a fall.
Absence Seizures consist of brief periods of staring and unresponsiveness. The patient usually stops what he or she is doing, then resumes the previous activities right after the seizure ends. Absence seizures are usually brief, lasting 10 to 30 seconds. Patients can have many absence seizures in one day.
Tonic-Clonic Seizures consist of sudden contraction of all the muscles of the body followed by repetitive jerking of the arms and legs, with unresponsiveness., This is the most severe type of seizures.
Focal seizures are seizures that start in a specific part of the brain called the epileptic focus. The symptoms experienced by the patient depend on the location of the focus. The brain has different areas that specialize in different functions. For example, there is a part of the brain that controls our movements, called the Motor Cortex and an area that controls our skin sensation, called the Sensory Cortex and so forth. If a seizure starts in the part of the brain that controls our speech, the first sign of a seizure would be inability to talk. The severity of each seizure depends on how much of the brain is involved. In general, we divide focal seizures into three types, which are actually three levels of severity.
Simple Partial Seizures are the mildest type of focal seizures. The patient remains fully conscious and aware during the seizure and is able to describe exactly what he/she is feeling. Examples of simple partial seizures include the Temporal Lobe Aura, which is usually described by patients as a Deja Vue sensation, or sometimes as a sense of fear and apprehension. Other types of simple partial seizures include sensory auras, which consist of a sensation of tingling involving one part of the skin.
Complex Partial Seizures are more severe and usually indicate that the seizure activity involves a larger area of the brain. There is usually some alteration in the level of consciousness. Patients may lose the ability to talk or understand and frequently become unresponsive and may stare out in space.
Secondarily Generalized Seizures are the most severe type of focal seizures and indicate that the seizure activity involved the entire brain. These seizures usually start with a complex partial seizure that does not stop and progresses into a generalized tonic clonic seizure.
Epilepsy is not a single disease, it actually consists of a large number of different disorders, that have in common the tendency to have seizures. Scientists and doctors try to classify the epilpsies into different syndrome. The easiest way to classify Epilepsy Syndromes is based on the types of seizures. So, patients who have focal seizures have focal epilepsy and patients with generalized seizures have generalized epilepsy. Another way of classifying epilepsy syndromes depends on whether or not the cause of the seizures is know or not. If the cause of seizures is not known, the epilepsy is called Primary or Idiopathic. If the cause is known, then the epilepsy is called secondary or symptomatic. This classification scheme is very simple and does not cover all epilepsy syndromes, however, it is easy to understand and results in four common syndromes:
Primary Generalized Epilepsy: seizures are generalized, the cause is not known, or genetic. One example is Juvenile Myoclonic Epilepsy.
Symptomatic Generalized Epilepsy: multiple types of seizures, the cause is usually known, and patients tend to have developmental delay. One example is Lennox Gastaut Syndrome.
Idiopathic Focal Epilepsy: seizures are focal, cause is unknown, and patients frequently outgrow their seizures by adolescence. On example is Benign Rolandic Epilepsy.
Secondary Focal Epilepsy: seizures are focal and are caused by a specific dysfunction or lesion in the brain, such as head trauma, stroke, malformation or a brain tumor.
How Do We Diagnose Epilepsy?
The diagnosis of seizures and epilepsy is not easy and should not be taken lightly, since it has major implications on the patient's life, like taking daily medications and the ability to drive. The first step is to determine if the patient is actually having seizures or not. Many types of symptoms can mimic seizures, and are caused by psychological, cardiac or other types of disorders. It is extremely important to know if the patient is having true epileptic seizures, as opposed to one of the "seizure mimics", also called non-epileptic seizures. A careful evaluation by a specialist can usually help sort this out. Once it is determined that the patient is having epileptic seizures, the second step is to know the correct epilepsy syndrome. Diagnosing seizures and epilepsy relies primarily on the careful description of the episodes by the patients or their families and on additional diagnostic tests, including EEG studies and Brain Imaging, like MRI. The third step is to decide if the patient needs to be on daily treatment or not. Finally, long-term issues need to be addressed, such as specific restrictions and the duration of treatment.
Treatment of Seizures and Epilepsy
The goal of treatment is to decrease the frequency or preferably eliminate seizures completely, without causing major side effects. Unfortunately, there are no known treatments that cure epilepsy completely, however, most available treatments are very effective in preventing seizures. There are four types of treatments commonly used, that include medications, diet therapy, epilepsy surgery and implanted devices.
Anti-seizure medications are commonly called Anti-Epilepsy Drugs (AEDs). There are currently over 20 different approved seizure medications and several are still being studied. The choice of medication depends on the type of seizures and the epilepsy syndrome, since certain medications work only for certain seizure types. In fact, some medications can even make certain seizure types worse. For this reason, it is crucial to make the correct diagnosis before choosing a medication. All medications have side effects, some more than others. Doctors take into account the type of side effects when choosing the appropriate medication for each individual patient. The choice of seizure medications is a decision made by the physician and the patient, after discussing the various possible options. About half the patients with epilepsy respond well to one seizure medication and their seizures become fully controlled. Some patients require the combination of two or three medications to achieve good seizure control. Unfortunately, some patients have seizures that are very difficult to control and don't become seizure free, even after trying several medications. When medications don't work, other treatment options are usually considered.
It has long been known that starvation can improve seizure control. In recent years, this phenomenon was studies scientifically and it was discovered that depriving the body of carbohydrates (sugars) can actually lead to a significant improvement in seizure control. This is thought to be due to changes in the energy source of the brain. The standard diet used as a treatment for epilepsy is called the Ketogenic diet. It is a very restrictive diet that requires very monitoring of the amount of food the patient eats and the amount of carbohydrates, fat and proteins. The diet requires the patient to consume a large amount of fat, a moderate amount of proteins and a very, very small amount of carbohydrates. It is essential that a qualified physician and dietitian be monitoring the patient with blood work and other tests to ensure safety. It is therefore not recommended that any patient starts this diet without proper supervision by a qualified physician. The Ketogenic diet tend to be difficult for patients and their families and it is easier to follow when patients have a feeding tube. A less restrictive diet is called the Modified Atkins Diet, which follows the same principles as the ketogenic diet, in being low in carbohydrates, high in fat and moderate in proteins, however, it does not require the same amount of work on the patient and their families. Therefore, the modified Atkins diet is more frequently used in patients who eat regular food. Again, the modified Atkins diet should not be attempted without proper supervision by a qualified physician and dietitian. Finally, the third diet that is sometimes used in epilepsy patients is called Low Glycemic Index diet. This diet is even less restrictive than the modified Atkins diet in that it allows a larger amount of carbohydrates, however, it does not seem to be as effective in treating seizures.
About 30% of patients with epilepsy continue to have seizures despite treatment with multiple medications. We call their epilepsy Medically Intractable Epilepsy. Some of these patients may be candidates for epilepsy surgery. Epilepsy surgery consists of identifying the part of the brain that is causing the seizures, then ensuring that it does not have any important functions. Once this is established with certainty, that the patient can undergo brain surgery with removal of the epileptic focus. Epilepsy surgery should only be performed in specialized Epilepsy Surgery centers by highly qualified neurologists and neurosurgeons.
There are several implantable devices that are either approved or being currently studies for the treatment of medically intractable seizures. The only device that is currently approved is called Vagus Nerve Stimulator (VNS). This device is implanted under the skin of the left chest and connected via electrical wires to a nerve in the neck called the Vagus Nerve. The device delivers a small electrical current to the nerve, which in turn, transmits the electricity to the brain. VNS is not for everybody. Some patients are good candidates and some are not. The implantation of the VNS or other devices should be discussed in depth with a qualified physician. In addition to the VNS, two other devices are currently being studied for epilepsy, but have not been approved. The first one is called Deep Brain Stimulation and the second is called Responsive NeuroStimulation. We will not discuss these devices here because they are not yet approved by the FDA and are not available for clinical use.
How Long Do We Treat For?
Patients frequently ask a very valid question: "how long should I be on medications for?" The answer to the question depends entirely on the epilepsy syndrome we are dealing with. Some epilepsy syndromes, such as Childhood Absence, Benign Rolandic Epilepsy or Benign Occipital Epilepsy are usually transient disorders, which means patients can outgrow them once they reach puberty. However, these are only a few syndromes. The majority of Epilepsy Syndromes are life-long and patients usually need to be on treatment for life. In general, if the epilepsy starts during childhood, it is reasonable to determine if the patient still needs to be on medications once they reach puberty, especially if they are seizure-free for over a year. The safest way to make that determination is to wean off the medications and record a prolonged EEG. Sometimes this is done in the hospital so that emergency medications can be given if the patient goes into a prolonged seizure. Another situation where seizures might be temporary is after head trauma. Some patients develop seizures right after a major trauma to their head. In some cases, seizures will eventually stop when the brain heals properly. In these cases, it is also reasonable to wean off the medications and record a prolonged EEG to assess the risk of seizures. This can usually help us decide if medications are still necessary.