What are the differences between blackouts, seizures and epilepsy?
The term “blackout” refers to any alteration of awareness or consciousness, and blackouts may have a wide range of causes. Blackouts may be as a result of sudden drops in blood pressure as in fainting, may have a cardiac cause, can be seen in sleep disorders, can have a psychological cause or may be as a result of neurological dysfunction, such as a seizure.
Seizures represent the sudden development of unregulated abnormal electrical activity within the brain. These uncontrolled electrical discharges result in a temporary disruption of neurological function. Depending on where in the brain and how widespread this electrical activity is, seizures may result in minor symptoms such as brief speech disturbance, tremor, or confusion, but if the electrical activity spreads throughout the brain, a generalised convulsion may result.
Epilepsy describes the tendency to have recurrent seizures in the absence of a clear physical trigger, and is usually diagnosed in this setting after two or more seizures. Occasionally epilepsy may be diagnosed after a single seizure, if investigations point to a high likelihood of another seizure.
What are the common causes of these conditions?
Seizures are not rare, and studies estimate a lifetime risk of 8-10% of having a seizure, while the lifetime risk of developing epilepsy is 3%. This discrepancy reflects that many people will have a single seizure, or will only have seizures when there is a physical trigger. Physical causes include an acute medical illness such as infection, disturbance of blood glucose or blood salt levels, certain prescribed or non-prescribed drugs, stroke, head injury, or alcohol intoxication or withdrawal.
Seizures in the absence of a clear trigger such as these are usually diagnosed as epilepsy. Common causes of epilepsy include the inheritance of certain genes, or an abnormality of brain structure (commonly as a result of scarring due to previous brain injury, stroke or infection, or abnormal development of the brain before birth).
Can adults develop these conditions later on in life?
Genetic/hereditary epilepsy syndromes will often come on in childhood or adolescence. In contrast, it is very common for epilepsy related to brain injury or damage to come on later in life, which would be expected, since conditions like stroke are very age-related.
What are the treatment options available?
Treatment very much depends on the individual. Once epilepsy mimics have been excluded, and a seizure has been confirmed, the decision to initiate treatment is based upon the underlying cause and what the risk of further seizures is. If there is a clear acute physical trigger, then treatment may not be required in the long-term. The majority of people will be treated with medication. The choice of drug is based upon the type of epilepsy, other medical issues or existing medications, and other issues such as a planned pregnancy. Other less usual treatments include surgery, or implanted nerve stimulators, but these treatments are usually reserved for highly selected individuals and are not appropriate for most people.