Epilepsy is a condition which causes seizures. Seizures happen when the normal electrical signals in the brain are over-run by uncontrolled and unorganised electrical interference. There are more than 40 different types of seizures from people becoming vacant or confused to odd rhythmic or repetitive movements, jerking or twitching of limbs, to convulsions that contract muscles throughout the entire body. Seizures can occur whilst people are awake or when sleeping and sometimes seizures begin with an aura. Auras are unusual feelings of sight, sound, smell, taste or touch that warn people of an on-coming seizure. For example, they may feel a cool breeze or a bright light and may include numbness or feeling sick. What happens during a seizure depends on which part of the brain is affected. Many people with epilepsy have similar symptoms with each seizure, but some may have a wide variety of symptoms. Rarely, less than 5% of people with epilepsy, the seizures are photosensitive meaning they can be triggered by flashing lights.
Most seizures last a few seconds to a few minutes. If a person’s consciousness is altered or lost, they may not remember what has happened. After a seizure some people feel normal, but others feel confused, may suffer from headaches, and can have weakness and tiredness for hours or even days afterwards. Most seizures do not have a lasting affect on the brain or body, but a loss of consciousness may lead to falls and injuries - especially if the affected person is driving, bathing, cooking, or doing other potentially dangerous activities. Seizures that last longer than 20 minutes are called status epilepticus. The longer a seizure lasts the more the risk of problems with breathing. Prolonged seizures, longer than 30 minutes, can increase the risk of permanent damage and can in some cases be fatal.
Not every seizure is epilepsy. Those that are due to other conditions such as a high fever in an infant, brain infections, pre-eclampsia or alcohol or drug withdrawal may not be called epilepsy. Some symptoms that look like a seizure are actually caused by problems in other parts of the body. Fainting, migraine headaches, narcolepsy, drug use, mental illness, heart conditions and many other medical problems can cause symptoms similar to a seizure.
Epilepsy is diagnosed when someone has two or more seizures, which are at least 24 hours apart, that cannot be explained by another diagnosis such as those mentioned previously. About 1 in 20 adults will experience a single seizure in their lifetime, but most will never have another one. There are about 600,000 people living with epilepsy in the UK affecting 1 in every 100 people according to leading epilepsy charities. While epilepsy can affect anyone, children (people < 20 years old) and adults over 65 are most likely to be affected. The majority of people with epilepsy will respond to treatment, but about 25-30% will continue to have seizures despite treatment. Any condition that affects the brain has the potential to cause epilepsy. This includes head injury, abnormal brain development, lack of oxygen during birth, brain tumours, strokes, diseases of the heart and it’s blood supply, toxins such as lead poisoning, infections, diseases of the brain and nerves, and disorders of the body’s chemistry. Some forms of epilepsy run in families and are related to genetic problems. The cause of epilepsy in many cases is unknown and Doctors refer to this as idiopathic epilepsy.
Epileptic seizures can be described as either partial (focal) or generalized. Partial seizures originate from a single location in the brain, while generalized seizures involve both sides of the brain. A few seizures may start as partial seizures and then become generalised, and spread to involve the whole brain. About 60% of people with epilepsy have partial seizures. For more information about types of seizures, visit the Epilepsy Foundation website and read the article Seizures and Syndromes.