A febrile seizure, also known as a fever fit or febrile convulsion, is a convulsion associated with a significant rise in body temperature, but without another underlying cause such as a Central Nervous System (CNS) infection (e.g. meningitis or encephalitis) or electrolyte imbalance. They most commonly occur in children up to the age of 6 (with only 10% of reported seizures occurring after the age of 3).
They are the most common form of seizure in children and were first written about over 300 years ago by Dr Thomas Willis.
There are three (3) types of febrile seizures:
- A simple febrile seizure (occurs in about 15 in 20 cases – 75%) is when the child may look hot and flushed and their eyes may appear to roll backwards. They may appear dazed and then become unconscious. The body may go stiff, then generally twitch or shake (convulse). It does not usually last long. It may only be a few seconds and is unusual for it to last more than five minutes. The child may be sleepy for some minutes afterwards but within an hour or so the child will usually appear a lot better when their temperature has come down. Another feature of a simple febrile seizure is that it does not recur within 24 hours or within the same febrile illness.
- A complex febrile seizure (occurs in about 4 in 20 cases – 20%) is similar to a simple febrile seizure but has one or more of the following features:
- The seizure lasts more than 15 minutes and/or …
- The seizure recurs within 24 hours or within the same febrile illness and/or …
- The child is not fully recovered within one hour. This does not mean the seizure lasts more than an hour but that it takes more than an hour for the child to look and behave more like their normal self and/or …
- The seizure has partial or focal features. This means that rather than a generalised twitch or shaking, only a part of the body may shake. For example, just one arm or just one leg.
- A febrile status epilepticus (occurs in 1 in 20 cases – 5%) means a febrile seizure that lasts for longer than 30 minutes.
For more information on the causes of febrile seizures please visit Latest Research.