What is Epilepsy?
Epilepsy is a neurological disorder that involves a tendency to experience recurring seizures, which are disruptions of the electrical activity in the brain. This may be the result of an underlying medical condition or injury, which makes a person susceptible to the seizures.
Having a seizure does not necessary mean a person has epilepsy. Epilepsy is not usually diagnosed until a person has had at least two seizures. People who have seizures that are caused by factors that can be controlled or avoided (e.g., certain medications or alcohol or drug use) are not considered to have epilepsy.
Epilepsy is one of the most common disorders of the brain and can occur in people of all ages. More than 2 million people have had an unprovoked seizure or have been diagnosed with epilepsy, according to the National Institute of Neurological Disorders and Stroke (NINDS). Most new cases of epilepsy are diagnosed in children under the age of 2 or in adults over the age of 65, according to the Epilepsy Foundation.
Epileptic seizures are the result of a sudden change in electrical activity in the brain. In normally functioning brains, neurons (nerve cells) produce electrochemical signals that instruct other parts of the body to do certain things, such as move or feel emotions or sensations.
A seizure occurs when something disturbs the pattern of electrochemical signals and causes the neurons to fire at a much faster rate than normal. This storm of electrical activity in the brain can result in changes in mood or behavior, hallucinations, involuntary muscle contractions or loss of consciousness. The symptoms experienced during epileptic seizures depend on the area of the brain affected.
Some people with epilepsy may experience unusual sensations or movements minutes or hours before they have a seizure. This sensation, called an aura, is actually a simple partial seizure. The exact nature of the aura is often unique to each individual, although it may include noticing a strange taste in the mouth, twitching in one limb or an inexplicable feeling of fear or apprehension. Because most people experience the same progression of events during each seizure, auras can serve as a warning that a seizure is going to occur.
Epilepsy is not a sign of brain damage – many people with epilepsy can function well between seizures. However, people with brain damage are more likely to develop epilepsy.
A serious complication of epilepsy is status epilepticus, a condition whereby a person has a longer than average seizure or never regains consciousness between seizures. People with epilepsy have an increased risk of status epilepticus, although it can also occur in people with no prior history of seizures. Seizures lasting more than 5 minutes are considered a medical emergency.
Having one seizure does not always mean that a person will have another seizure or has epilepsy. Many seizures are classed as first seizures. First seizures may be caused by a reaction to anesthesia or certain medications. They may also be the result of withdrawal from alcohol or drugs. However, in many cases, there is no known trigger for a first seizure. Only a small proportion of people who have first seizures develop epilepsy, although the risk of developing epilepsy is increased in people who have experienced a seizure.
People may have seizures that are unrelated to epilepsy. For example, young children with high fevers may develop febrile seizures. Pregnant women may develop a serious condition called eclampsia that involves seizures. Some people appear to have seizures, but there is no evidence of abnormal electrical activity in the brain. These are called pseudoseizures and they may be psychological in nature, resulting from stress or other medical conditions. Some people with epilepsy may experience pseudoseizures in addition to actual seizures.
How is it diagnosed?
Diagnosis of epilepsy usually begins with a medical history and physical examination. Because there are many different types of seizures, some of which are not related to abnormal brain activity, it is important that a physician identify the type of seizure a patient has had. The physician may ask questions that relate to:
- What sensations the patient feels before, during or after a seizure
- How long the seizure normally lasts
- Which side of the body is most affected during a seizure
- To what extent the patient experiences a change in or loss of consciousness
- Whether the patient feels any pain before, during or after the seizure
In addition to the medical history and physical examination, a physician may conduct tests to assess which areas of the brain may be involved in the seizures. These tests may include:
Electroencephalogram (EEG)An EEG is one of the most common tests that a physician may conduct following a seizure. During an EEG, electrical activity in the brain is monitored through electrodes placed on the scalp. People with epilepsy may show abnormally slow frequencies or spikes and other disruptions, even when they are not having a seizure. A physician may request that the EEG be performed while the patient is sleeping to get an accurate picture of normal brain activity.
Computed axial tomography (CAT) scanA CAT scan is a noninvasive or minimally invasive test that uses a rotating x-ray device to create detailed cross-sectional images of different body parts, including the brain. It can be used to identify tumors or other abnormalities in the brain that may be causing a patient's recurring seizures.
MRI (magnetic resonance imaging)An MRI is a noninvasive procedure that uses powerful magnets and radio waves to produce clear, cross-sectional and three-dimensional images of the body's tissues. Like the CT scan, it can be used to view the brain and identify abnormalities. A special kind of MRI, called a functional MRI (fMRI), can be used to allow physicians to see how the brain functions. During an fMRI, the patient may be asked to perform a task while the machine scans the brain and records its activity. This can then be used to gauge which parts of the brain are functioning abnormally.
Blood testsBlood samples may be taken to screen for conditions such as diabetes, infection or anemia, which may be the causing a patient's recurrent seizures. Blood tests may also be used to identify metabolic or genetic disorders that may be related to the seizures.
How is Epilepsy treated?
There is no cure for epilepsy. However, 80 percent of people with epilepsy are able to effectively control their seizures through various treatment methods. Treatment should begin as soon as possible after diagnosis. Studies have shown that patients are more likely to be able to control their seizures effectively if treatment is started early.
The most common treatment method for epilepsy is the use of anticonvulsant. These medications attempt to control the area of the brain that triggers the seizures. For this reason, it is important that a patient's seizures be accurately classified before treatment is started. Patients are usually prescribed a low initial dose of one type of anticonvulsant. Their progress will then be monitored by a physician to assess if the anticonvulsant is effective or if the dosage level needs to be adjusted. Patients should understand what side effects are possible so they can report them to their physician. In some cases, a patient may require two types of anticonvulsants to control the seizures.
For some people with epilepsy, medications fail to control their seizures. In these cases, a physician may recommend additional treatment methods that may be used with medications. These treatment methods include:
SurgerySurgery may be considered if a physician thinks that the patient is unlikely to respond to medication. It usually involves removing a small area of the brain. Tests such as electroencephalograms (EEGs) and magnetic resonance imaging (magnetic resonance imaging) may be used to identify the area of the brain triggering the seizures. A surgical team will assess whether the portion of the brain to be removed is close to areas that control motor function, sensations or language. Complications from brain surgery are rare. Studies have shown that most people with epilepsy who have surgery either stop having seizures or the frequency of their seizures is drastically reduced.
Vagus nerve stimulationThe vagus nerve is a cranial nerve that originates in the brain stem and controls numerous organs in the body. People with epilepsy that cannot be controlled through medication may have an electronic device surgically implanted under the skin of the chest and attached to the vagus nerve in the lower neck. This device stimulates the vagus nerve through a series of small shocks. These shocks can reduce seizures in people with epilepsy by 20 to 40 percent, according to the NINDS.
DietThere is evidence that a diet that is low in carbohydrates and high in fat can help control seizures in some patients, especially children. This type of diet is called a ketogenic diet because it forces the body to enter a state called ketosis where it burns fat instead of carbohydrates to function. Although there is evidence to support the ketogenic diet as a treatment method, the diet is difficult to maintain and may result in nutritional deficiencies, which can be especially damaging for children.
Depakote (Divalproex), Diamox (Acetazolamide), Tegretol (Carbamazepine), Topamax (Topiramate), Mysoline (Primidone), Trileptal (Oxcarbazepine), Klonopin (Clonazepam), Valium (Diazepam), Ativan (Lorazepam)
Learn as much as you can about your seizure medication. The drugs used cause significant side effects, in addition to suppressing seizures.
What might complicate it?
Prolonged or repeated seizures, without a period of recovery, is a condition called status epilepticus. If the type of seizure is grand mal, status epilepticus can be fatal without emergency treatment and intravenous anticonvulsant drugs. Temporal lobe seizures, a type of focal epilepsy caused by severe brain damage, are more difficult to control. Non-compliance with drug therapy, though not a complication per se, must be addressed. Medications may need to be changed to those more tolerable for the individual. Also, some epileptic seizures may not respond to anticonvulsant medication.
It is estimated that at least one-third of those suffering from epileptic seizures will eventually outgrow the condition. Another third find their seizures become less frequent while on anticonvulsant medication. The remaining third find their condition remains the same. In most cases, the number one cause of repeat seizures in known epileptics is due to non-compliance with drug therapy.
Neurologist and neurosurgeon.
Last updated 1 July 2015