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What is epilepsy?
Epilepsy is a relatively common condition of the nervous system, during which a person has repeated seizures. Epilepsy can be found in all ages, genders and cultures. Up to a third of epilepsy cases start during childhood, though it is common for children to outgrow the condition.
Epilepsy is not contagious, nor is it linked to intellectual disability or mental illness. There is no cure, but most cases of epilepsy can be managed by medications.
The brain is divided into two hemispheres, comprising four lobes - frontal, parietal, temporal and occipital - that each control different functions of the body. Each lobe is made up of millions of nerve cells, called neurons, which use electrical signals to communicate messages to various areas of the body. When faults occur in these signals, they cause an abnormal reaction, called a seizure or fit. Having just one seizure is not considered to be epilepsy; rather, epilepsy refers to a range of conditions characterized by recurrent seizures.
Half of all cases have no known cause. The other cases can be due to a wide range of causes, including:
- Infections of the brain, such as meningitis and encephalitis;
- Brain injury;
- Chronic alcohol or recreational drug use;
- Brain tumor;
- Abnormal brain development, such as cerebral palsy;
- Genetic risk factors - a number of epilepsy types have been linked to genetic mutations;
- Lennox Gastaut syndrome - this severe epilepsy syndrome usually appears before the age of five and needs lifetime medical management, and;
- Metabolic disorders - some rare metabolic conditions, such as phenylketonuria (PKU), can cause seizures if left untreated.
There are many types of seizures, with some people exhibiting a combination of seizure types. Seizure types can differ depending on the region of the brain it originates in. These include:
Partial (focal) seizures
In partial seizures, the seizure originates in and affects just one hemisphere of the brain. These account for a majority of epilepsy cases. Partial seizures can have two subtypes:
Simple partial seizures
Simple partial seizures affect only a small region within a hemisphere. The symptoms vary according to where the seizure occurs. A person may experience unusual sensations and feelings such as fear, nausea, joy or anger while remaining conscious throughout. Alternatively, they may smell, hear or taste things that do not exist, but seem real to them.
Complex partial seizures
Complex partial seizures affect a greater region within a hemisphere. They often start off as an 'aura' or an unusual feeling, warning them they are about to have a seizure. This leads to a change in consciousness, often creating a dreamlike state in which a person performs involuntary, repetitive actions (automatisms), such as moving their mouth or blinking. They may still continue to perform routine tasks, but these are pointless or unproductive.
Partial seizures can lead to generalized seizures.
Generalized seizures occur when the abnormal electrical activity spreads through both hemispheres of the brain. It results in loss of consciousness and is often followed by confusion once the seizure resolves. There are five main subtypes of generalized seizures:
Absence seizures (Petit Mal)
The person will suddenly stare off into the distance and have no memory of the incident afterwards. Often first appearing in childhood, these can be misinterpreted as vagueness, daydreaming or simply 'zoning out'.
Tonic-clonic seizures (Grand Mal)
The person suddenly loses consciousness, drops to the ground and often emits a cry. The body usually goes stiff (tonic) before making jerking (clonic) movements, which can be distressing to watch. Often the person will lose bladder control, bite their tongue and, due to lack of oxygen, their lips may appear blue (cyanosis). Afterwards the person may get a headache and be agitated, tired and sore.
The person will experience jerking movements on both sides of the body.
The person may have sudden loss of muscle tone, either falling over suddenly or with just their head drooping.
These cause jerking or twitching movements of the arms, legs or upper body and usually involve both sides of the body.
Not all seizures are due to epilepsy. A range of other conditions can also cause seizures:
During pregnancy, this life-threatening condition may lead to seizures and elevated blood pressure, requiring immediate hospitalization. After delivery, the mother usually returns to normal health without further symptoms.
Many people experience a one-off seizure, due to a reaction to strong medications or for no known reason. Usually there are no further seizures unless there is a brain abnormality, family history or brain damage discovered.
What can trigger a seizure?
Common triggers for seizures include:
Signs and symptoms
Most seizures last less than a few minutes, but some may last longer. Seizures can result in repetitive, jerking movements (convulsive seizures), but also other unusual feelings, sensations and behaviors (non-convulsive seizures). These non-convulsive seizures can depend on the regions of the brain that are affected and include:
- Unresponsive staring episodes;
- Repetitive movements (automatisms) such as walking in circles, chewing or picking at objects;
- Sudden dropping to the ground or slumping over (known as 'drop attacks');
- Feeling odd sensations, tastes, sounds, and smells, and;
- Suddenly feeling sad, angry, joyful or nauseous.
In simple partial seizures, individuals remain conscious, whereas in complex partial and generalized seizures, a person's consciousness is altered.
Some people report an 'aura', which are feelings or sensations that precede a seizure. They serve to warn people that they are about to have a seizure. During convulsive seizures, people may accidentally bite their tongue, and lose control of their bladder and bowel. Following generalized seizures, people can often feel confused.
There are over 40 different types of epilepsy syndromes, with different patterns of symptoms.
Methods for diagnosis
A doctor will take a person's detailed history about previous seizures, illnesses, family history and relevant symptoms, to investigate the type of seizure being experienced. As the patient may not remember what happened during a seizure, any information from caregivers or bystanders can be helpful.
Neurological, developmental and behavioral testing
Motor skills, intellectual ability and emotional behaviors may be tested.
Electroencephalogram (EEG) monitoring
This test examines the electrical activity in the brain using video monitoring and electrodes, which are applied to the scalp. It can be performed while awake and/or during sleep, to detect any abnormal brainwave patterns. This test can help identify the type and origin of epileptic seizures.
The following scans can be used to evaluate the brain activity:
- Magnetic resonance imagining (MRI) and functional magnetic resonance imaging (fMRI) - These scans use a magnetic field and low-energy radio waves to examine the brain in detail. They help identify any physical abnormalities in the brain that could give rise to epilepsy;
- Computerized tomography (CT) - the CT scan uses X-rays to obtain an image of the brain, which can also provide information about any physical abnormalities that might cause epilepsy;
- Positron emission tomography (PET) - injecting radioactive dye into the brain will enable closer inspection of its structures, especially to plan for any surgical treatment, and;
- Single photon emission computed tomography (SPECT) - this type of scan may be used if neither the MRI nor EEG have identified the part of the brain involved in seizures. A 3D map can be produced showing blood flow into the areas that are active during seizures.
Types of treatment
How to manage a seizure?
The first-aid management of an unconscious person with a seizure requires you to time the seizure if possible and to protect the person by:
- Removing any hard objects near them that could cause injury;
- Protecting their head by placing something soft under it;
- Not attempting to restrain the person or stop the jerking, and;
- Not putting anything in their mouth.
Gently roll the person onto one side and stay with them, talking calmly to them until they regain consciousness.
If the person does not regain consciousness between repeated seizures, they are continuous, or last more than five minutes, call an ambulance immediately. Also call an ambulance if the person is not a known epileptic and is experiencing a seizure.
The first-aid management of a person with confusion due to a seizure is as follows:
- Gently guide the person past obstacles and away from dangerous places, and;
- As the seizure finishes, calmly talk to the person until they return back to normal.
Long-term management of epilepsy
Doctors will normally try to first control epilepsy with medications. This may take some time and experimentation, as the dosage is balanced to achieve optimum effect and minimize the side effects. With most forms of epilepsy, the sooner treatment begins, the better the outcome. If the medications do not work, the next step will be to look at diet, surgery, or the possible insertion of a biomedical device with electrodes (similar to a pacemaker) near the collarbone to send signals to the vagus nerve, which runs from the brain stem to the abdomen. This has been shown to reduce the occurrence of seizures.
Antiepileptic drugs (AEDs) are used to reduce the frequency and severity of seizures. Some can stop seizures completely, but cannot cure epilepsy. While some AEDs may need to be taken long-term, some are phased out over a few years, as symptoms lessen. There are different types of AEDs available; some affect the electrical activity between brain cells by controlling the passage of potassium, sodium, calcium and chloride ions through the cell membranes. Other AEDs work by changing the chemical messages (neurotransmitters) sent between the brain cells. It is vital that a person never suddenly stops taking AEDs, as this can cause severe seizures. Common side effects of AEDs are headaches, nausea, dizziness, rashes and weight changes. Contact a doctor immediately if a skin rash develops while taking AEDs, as this is one sign of a potentially fatal drug reaction.
If seizures are due to an abnormality within a certain area of the brain (focal point), surgery may be offered to remove the affected region. Extensive testing is essential to ensure the correct area is targeted and no damage caused to vital functions such as vision, speech or movement. Surgery is therefore performed only under a local anesthetic, enabling the patient to stay conscious while the surgeon checks the functionality of vital areas before and during the operation. Prior to any surgery, there is an extensive period of testing/examination and counselling over several months, to make sure this is the right solution and to weigh the benefits against any possible side effects. Removing the affected part of the brain can result in lessening of seizures or in some cases, stop them all together. However, some cases cannot be operated on, due to the sensitive location of the affected area.
This is a high-fat and low-carbohydrate diet often recommended for children with severe seizures who do not respond well to medication. The basis of the diet is to get the body to burn fats instead of glucose (sugars), which seems to affect brain chemistry thereby reducing seizures. Due to the diet potentially causing nutritional deficiencies, this procedure requires the close supervision of a dietitian.
Vagus nerve stimulation (VNS)
The vagus nerve in the neck is stimulated with an electrical device similar to a pacemaker placed in the chest, just under the skin. It sends electrical impulses to the nerve. It is not understood how it works, but VNS can, in some cases, reduce seizures by 20-40%, enabling a reduction in prescribed medication. VNS is used for focal seizures in people aged over 12 who do not respond well to medication. Side effects are coughing, a sore throat and problems with breathing during sleep (sleep apnea).
In the US, all states allow people with epilepsy to drive. Each state has its own regulations and they can vary greatly. The Epilepsy Foundation has a searchable database of state regulations on its website. You can visit the your state's department of motor vehicles (DMV) website to find the requirements in your state.
In all cases, people with epilepsy must report their condition to their state's DMV. However, states require different people to do the reporting. Some want the doctor to contact the DMV. Others need the person with epilepsy to sign a simple form at the time of application for a license or renewal that says they'll notify the DMV of changes in their health status or driving ability.
Mental health issues
People with epilepsy are at higher risk of developing depression and anxiety. This may be due to medication side effects and not feeling 'normal' due to social embarrassment from having seizures. Lack of independence and social exclusion may also contribute to depression.
There is a much higher risk of drowning while swimming or bathing for anyone who suffers from seizures or epilepsy.
Many antiepileptic medications can cause birth defects, so it is important for a woman with epilepsy to talk to their doctor prior to becoming pregnant. As seizures can be harmful for both the mother and unborn child, close medical monitoring is also required during pregnancy.
Sudden unexplained death in epilepsy (SUDEP)
Although incredibly rare, people with epilepsy are at greater risk of sudden unexplained death. The reason for this is unknown, but may be due to changes in the heart or brain function. Those with uncontrolled epilepsy face an even higher risk.
Status epilepticus (SE)
This is when a seizure lasts for more than five minutes, or the person has continuous seizures. This condition requires urgent medical attention as it can lead to permanent brain damage or death.
The outlook for the majority of people with epilepsy is positive, with most leading a full and active life. Medical research continues to explore genetic factors, and brain surgery is now a highly advanced and safe procedure. With the use of biomedical devices, antiepileptic medications, specialist diets and lifestyle modifications, many will be able to control most of their symptoms. Epilepsy that starts in childhood usually improves or even disappears with age.
There are several things a person can do to reduce the chances of seizures:
- Avoiding head injury by wearing a safety helmet while riding a bicycle, or a seat belt while driving;
- Avoiding dangerous activities such as skydiving;
- Learning to recognize triggers that may bring on a seizure, such as stress, recreational drugs, tiredness, strobe lighting, hunger, alcohol, fevers or hormone changes during menstruation;
- Avoiding swimming alone or cycling in remote areas, due to the risk of death or injury;
- Avoiding dangerous occupations, such as operating heavy machinery, or working with live electricity;
- Avoiding driving a car, unless cleared by their doctor, and;
- Wearing a medical alert bracelet in case of a seizure while alone or in public.