Epilepsy is a relatively common condition in which the electrical and chemical activity of the brain loses its usual co-ordination for short periods of time. These times of unco-ordinated brain activity are called seizures,fits or convulsions.
Epilepsy is not the only reason that someone may have a seizure — fever, excess alcohol use, illicit drug use, head injuries, brain infections such as meningitis, and a number of other conditions may also cause seizures. However, epilepsy is characterised by recurring seizures.
Different types of seizures
Epilepsy can cause several types of seizures. They can be roughly divided into generalised seizures and partial seizures. Generalised seizures arise from abnormal electrochemical activity affecting the whole brain at the same time. Partial seizures arise from abnormal electrochemical activity that starts in one particular part of the brain and may subsequently spread to other areas of the brain.
The part of the brain experiencing abnormal electrochemical activity determines the symptoms a person will have. Common symptoms of epilepsy are:
- an altered state of consciousness;
- abnormal body movements;
- altered sensations; and
- behavioural changes.
Some seizures are subtle and may not be noticed by other people, while other types of seizures, especially those that affect body movement, have very obvious signs.
- Tonic-clonic seizures involve the whole brain and cause a person to lose consciousness. The person may cry out at the start of the seizure. Their body tends to go stiff and they will fall to the ground and have repeated jerking movements. They may dribble saliva or vomit, and may lose control of their bowel and bladder. The seizure usually lasts a couple of minutes, and breathing may stop for part of this time, resulting in a bluish tinge to the skin. After the seizure the person may feel confused or agitated; they may also have a headache or muscle pain. They often remain drowsy for several hours and want to sleep.
- Absence seizures most often begin in childhood and result in an altered state of consciousness, lasting several seconds, during which time the person seems to ‘tune out’ and be unaware of their surroundings. Their eyelids may flutter and their eyes may roll upwards. When the seizure finishes the person usually resumes their current activity, although they will not have been aware of anything around them during the seizure. This can adversely affect a child’s schooling if absence seizures are occurring several times a day. Although absence seizures have subtle signs, they do involve the whole brain, and so are considered a type of generalised seizure.
- Myoclonic seizures cause very brief jerky movements, usually of the upper body, without loss of consciousness. They can cause the person to spill a drink they are holding or fall off a chair. One type of epilepsy that causes myoclonic seizures is juvenile myoclonic epilepsy. This condition typically affects teenagers and causes myoclonic seizures soon after waking.
- Tonic seizures are a brief stiffening of the whole body causing the person to fall to the ground. Tonic seizures tend to occur in people with severe epilepsy.
- Atonic seizures often begin in childhood. They also cause a person to drop to the ground as all the muscles of the body suddenly and briefly lose their tone (become floppy). There is no loss of consciousness; however, as injuries to the head are likely during the fall, people who have atonic seizures may choose to wear a protective helmet.
- Simple partial seizures affect only one part of the brain and usually last less than a minute. The symptoms will depend on which part of the brain is affected. Some partial seizures only involve altered sensations such as an unpleasant taste or smell, stiffening of muscles, a sensation of fear, or an abnormal feeling, such as numbness, in one part of the body. Others involve stiffening or abnormal movements of isolated muscle groups, for example, twitching of the face. The person does not lose consciousness in a simple partial seizure.
- Complex partial seizures involve an altered state of consciousness. The person may appear confused, stare blankly, be unresponsive or respond inappropriately, and they may have altered movements such as repetitive fiddling with clothing, lip smacking, chewing, mumbling or wandering.
- Secondary generalised seizures. Sometimes a partial seizure can be followed by a generalised seizure, in which case the symptoms of the partial seizure are called an aura or warning period that precedes the generalised (usually tonic-clonic) seizure. The resulting seizure is called a secondary generalised seizure.
Some people may have epilepsy that is characterised by more than one type of seizure.
Causes of epilepsy
Epilepsy often starts in childhood, although it can begin at any age.
Although the cause of the epilepsy cannot be established in about half of those people who have epilepsy, there are several known causes, such as the following:
- an inherited disposition towards epilepsy in the family;
- the brain being damaged at birth;
- a period of anoxia (an absence of oxygen) affecting the brain;
- an accident that results in a brain injury; or
- an infection, blood clot or other illness that affects the brain.
Epilepsy starting in infants may be caused by birth injuries, abnormalities present from birth or infections of the central nervous system. Seizures starting in adult life are likely to be caused by a disease or injury affecting the brain. For example, elderly people may develop epilepsy after a stroke.
Treatment of epilepsy
Epilepsy is treated with prescribed epilepsy medicines that aim to prevent seizures. Many people who have epilepsy take these medicines for a number of years. Your doctor may be able to gradually reduce the dose of your epilepsy medicines and possibly eventually stop them if several years have passed without you having a seizure. Leading a healthy and balanced lifestyle is also important in managing epilepsy.
Surgery is a treatment option for some people who have severe epilepsy. However, surgery is usually reserved for when medicines have failed to control the seizures and when doctors can identify the precise location of the abnormal electrochemical activity within the brain and that area can safely be operated on. As surgery for epilepsy does not have a 100 per cent success rate, it must be considered carefully.
For most people, epilepsy can be well controlled, and they can lead a full and active life.
Last Reviewed: 11 September 2009
- 1. Lowenstein DH. Seizures and epilepsy. Ch 363. In: Fauci AS, Braunwald E, Kasper DL, et al, eds. Harrison's principles of internal medicine. 17e. New York: McGraw Hill. Available from: http://www.accessmedicine.com/resourceTOC.aspx?resourceID=4 (accessed Nov 2009).