Febrile seizures

A seizure during a high temperature is one of the most frightening things a parent can be handed. The child stiffens without warning, the eyes roll up, the jerking starts and there is no response to their name. It looks like dying. In reality about one child in twenty goes through a febrile seizure, almost always without consequence: the brain is not harmed by it, development is unchanged, and most children have grown out of them by the time school starts. There are still two reasons to read this page in advance — how to behave during the three minutes it lasts, and how not to miss the infection behind it that genuinely is dangerous.

What a seizure looks like

It comes while the temperature is climbing, often in the first hours of an illness, sometimes before anyone has noticed the fever at all. The typical picture is this: the child loses consciousness, the whole body tenses and stretches out, and then the arms and legs begin jerking rhythmically. The eyes are open and rolled upwards, the breathing turns hoarse and uneven, the lips may go blue, froth or saliva comes from the mouth and the child may wet themselves. There is no reaction either to your voice or to touch.

It usually lasts two or three minutes, however much like half an hour it feels to whoever is watching. Afterwards the child is limp and bewildered, and may be fretful or sleep heavily; an hour or so of that is normal. It also happens with consciousness only partly lost: the child goes floppy and stares into space with no jerking at all.

Doctors care about telling two versions apart. A simple seizure involves the whole body, lasts under a quarter of an hour and happens once in twenty-four hours; most are of this kind. A complex one is the seizure that drags on, repeats within the same day, or affects only one half of the body — arm and leg on one side, head and eyes turned to one side. The difference is not in how bad those minutes are but in the fact that a complex seizure calls for a more careful look. The usual age runs from six months to five or six years, most often around eighteen months.

What to do during those minutes

The main rule is simple: a seizure cannot be stopped, it can only be waited out safely. Your job is to keep the child from being hurt and to keep the airway clear.

• Look at the clock and hold on to the start time. It is the one fact a doctor will ask you for afterwards and the one nobody but you knows.
• Lay the child on the floor or on a wide bed, away from corners, radiators and furniture. Lift them down from a high changing table.
• Put something soft under the head: a folded jumper, a cushion, your own hand.
• Loosen the collar and take off anything extra.
• Once the jerking stops, roll the child onto their side, so that saliva and vomit run out and the tongue does not block the airway.
• Stay beside them until it is over and, if you can manage it, film what is happening on your phone. A video is worth a page of description.

What must not be done: holding the child down by force and straightening their arms and legs; prising the jaws apart and putting anything in the mouth, whether a spoon, a finger or a dummy (the tongue does not get swallowed, whereas teeth and fingers do get damaged); giving medicine, water or food before consciousness returns; and dousing with cold water or wiping down with alcohol or vinegar to "bring the fever down". Chilling a child abruptly does not end the seizure and is poorly tolerated.

When to call an ambulance

Call an ambulance (across Europe the single emergency number is 112) if:

• this is the first seizure of the child's life; there is no alternative here, a doctor has to examine them;
• the seizure lasts more than five minutes or is not stopping;
• a second one follows straight after the first, or there has been more than one in twenty-four hours;
• the child is under six months old;
• the jerking involves only one side of the body;
• breathing is laboured afterwards, or the child stays blue or very pale;
• consciousness has not returned after an hour, or the child does not recognise their own family;
• an arm or a leg is not working as it did before the seizure.

A child who is still seizing or has not come round is not driven to hospital in the family car — you call an ambulance. If a doctor has already prescribed you a rescue medicine for seizures, give it exactly as you were taught and be sure to tell the crew that you have.

What matters more than the seizure itself

Febrile seizures are almost harmless in themselves. The danger lies elsewhere: meningitis and encephalitis begin in exactly the same way, and in a small child those illnesses do not produce the familiar adult signs. That is why, after a seizure, a doctor is looking less for the cause of the jerking than for the source of the fever.

Signs where the count is in hours: a rash of small red or purple spots and blotches that do not fade when pressed with a clear glass; a tense or bulging fontanelle in a baby; a stiff neck and an inability to bring the chin to the chest; sudden intolerance of light; an odd, high-pitched, monotonous cry; refusing feeds along with constant drowsiness; cold hands and feet on a burning-hot body; mottled, grey or marbled skin. Any one of these is enough to set off immediately rather than wait and see how the morning looks.

There is a second line of reasoning too. A seizure in a child with an obvious infection — an ear infection, the picture of an ordinary viral illness — is one thing. If the fever has no explanation, if the urine shows changes, or if the child has recently had antibiotics that could have blurred the picture, the doctor checks more thoroughly.

What happens in hospital

After a first seizure the child is usually kept a few hours for observation, less often overnight. The core of it is an ordinary examination: the doctor hunts for the focus of infection, looks at throat, ears, chest and skin, and assesses consciousness and neurological signs. Then, depending on the case, blood and urine tests are taken, and if meningitis is suspected a lumbar puncture is done — a needle draws off a little fluid from beneath the coverings of the brain so that it can be checked for inflammation and for the organism causing it. The dread of the puncture is misplaced: children tolerate it well, and the harm from a missed meningitis is incomparably greater.

Brain wave recordings and scans are not done after a simple seizure, because they add nothing. They are kept for complex or prolonged seizures, for one-sided ones, and for cases where neurological changes persist after the child has come round. And what gets treated is not the jerking but the illness that produced the fever.

Will it happen again, and can it be prevented

It recurs in roughly a third of children, either during the same illness or with the next high fever. The likelihood is greater if the first seizure came in the first or second year of life, if it has already happened in the family, and if the jerking began at a temperature that was not especially high or almost as soon as it started rising.

The honest answer about prevention is an unwelcome one, but it matters: the seizure cannot be prevented. Fever medicines given in advance and by the clock do not reduce how often febrile seizures happen, and this has been tested more than once. There is a different reason to give them, which is comfort: a feverish child feels wretched, will not drink and will not sleep. The usual children's fever medicines in the dose for their age are what suit; aspirin and other salicylates are not given to children and teenagers with a fever. Taking anticonvulsants regularly just in case is not prescribed for most children, because the side effects outweigh the benefit. The exception is the rare child with frequent, drawn-out seizures: there a doctor supplies a medicine to be given into the cheek or rectally and explains in detail when and how to use it.

A fever after a vaccination sometimes triggers a seizure as well. That is not a reason to skip vaccinating: the illnesses being vaccinated against cause high temperatures too, along with far worse complications. Tell the doctor that your child has had febrile seizures and get advice on the days after the injection.

Seizures and epilepsy

Febrile seizures are not epilepsy, and one does not turn directly into the other. In children who have had a simple seizure the risk of developing epilepsy later is raised only very slightly compared with any other child, and the difference is small enough not to change how a family lives.

The risk is more noticeable in a different group: children with complex and repeated seizures, with developmental delay, or with epilepsy among close relatives. Those children are followed by a neurologist, and that attention is not an alarm signal but a sensible precaution. And one more thing people often ask about: febrile seizures do not affect memory, speech, school performance or temperament.

Online consultation

A remote appointment is a good place to work through everything left over afterwards: why it happened, what to expect with the next illness, how to take a temperature and when to give fever medicine, what to keep in the medicine cupboard and which signs mean calling an ambulance. The doctor will go through your account of the seizure or the video you filmed, explain how a simple seizure differs from a complex one and when a neurologist is needed. It is also a calm way to discuss vaccinations and the routine of a child who has just been through one. The seizure itself is not managed remotely: if it is happening right now, or if it is the first, you need an ambulance.

This material is for information only and does not replace medical advice.