Febrile Convulsion in a Child: A Reassuring Case

The case: a frightening few minutes

In our teaching scenario, a healthy eighteen-month-old girl has been off-colour with a cold and a rising temperature. Suddenly she stiffens, her eyes roll, and her arms and legs jerk rhythmically. She is not responding to her parents' voices. Understandably terrified, they think the worst. The seizure lasts around ninety seconds, then stops on its own. Afterwards she is sleepy and floppy for a while before gradually returning to herself. Her parents call for advice and she is checked over. This sequence, a brief whole-body seizure during a fever in an otherwise well young child, is the classic picture of a simple febrile convulsion, and it is far more common than many people realise.

Why fevers can trigger seizures

Febrile convulsions affect a noticeable minority of young children, usually between about six months and five years of age. The developing brain at this age is simply more sensitive to a rapid change in temperature during an infection. It is often the speed at which the temperature rises, rather than how high it gets, that seems to trigger the event. The infections behind them are usually everyday ones such as coughs, colds, ear infections or tummy bugs. Importantly, a febrile convulsion is not epilepsy, and it does not mean the child has brain damage or will grow up with learning problems. There is often a family history, as the tendency can run in families.

Simple versus complex, and why it matters

Doctors divide febrile convulsions into two types. A simple febrile convulsion, like the one in our case, lasts under fifteen minutes, involves the whole body equally, and does not happen again within the same illness. These make up the large majority and are very reassuring. A complex febrile convulsion lasts longer, affects one part of the body more than another, or happens more than once in the same illness. Complex ones, and any first seizure, need closer assessment to be sure nothing more serious is going on, such as a brain infection. This is why doctors ask careful questions about exactly how long the seizure lasted and what it looked like.

What to do if it happens

If a child has a febrile convulsion, the priority is to keep them safe and time it. Gently place them on their side in the recovery position to protect their breathing, move away anything hard they could knock against, and stay with them. Do not put anything in their mouth, do not try to restrain their movements, and do not put them in a bath to cool down. Most seizures stop by themselves within a couple of minutes. Note the time it starts. If it lasts more than five minutes, if breathing looks difficult, if the child turns blue, or if it is their first ever seizure, phone 999 without delay.

After the seizure and looking ahead

After a simple febrile convulsion the child is usually checked to find and treat the cause of the fever, and to make sure there is no serious infection. Many are safely cared for at home once assessed. Parents naturally worry it will happen again, and it can: a proportion of children have a further febrile convulsion during another illness, though most simply grow out of the tendency by around age five or six. Routinely giving fever medicines to try to prevent them does not reliably work, so the focus is on keeping the child comfortable and treating the underlying infection. The strongest message from this case is that these events, though terrifying to watch, are usually harmless.