Seizures caused by a high fever as a result of infection in a part of the body other than the brain
A febrile convulsion is the most common type of seizure in childhood and may affect as many as 1 in 20 children. The disorder occurs slightly more often in boys. Usually, a febrile convulsion occurs in the first 24 hours of a viral infection, such as a sore throat or common cold. Sometimes, a seizure may occur in association with a bacterial infection, such as an infection of the ears or upper respiratory tract. The convulsion develops in response to a rapid increase in body temperature that triggers an abnormal burst of electrical activity in the cells of the child’s brain.
A febrile convulsion causes jerking body movements and is alarming for parents. However, the disorder is rarely serious, and it does not indicate a brain defect or epilepsy. Febrile convulsions sometimes run in families.
The symptoms of a febrile convulsion may include:
Loss of consciousness.
Stiffening of the arms and legs and arching of the back.
Abnormal movements of the limbs.
Rolling upwards of the eyes.
A slight pause in breathing, which may result in a bluish tinge to the skin.
A febrile convulsion usually lasts for about 2–4 minutes and always less than 15 minutes. Your child will probably fall asleep afterwards. If your child has a seizure of any kind, you should contact the doctor immediately. If the convulsion lasts for longer than 5 minutes, call an ambulance at once.
You should not try to restrain a child who is having a febrile convulsion but protect him or her from injury by placing nearby objects out of reach and surrounding the child with pillows or rolled-up towels or blankets. After the convulsion is over, and when the child is fully conscious and awake enough to be able to swallow, he or she should be given a dose of liquid paracetamol (see Painkillers), which also helps to lower body temperature.
The convulsion is likely to be over by the time the doctor sees your child. He or she will perform a physical examination to make sure that your child’s temperature is coming down and to look for possible sources of the fever. The doctor may arrange for your child to be admitted to hospital, particularly if his or her body temperature remains high. A sample of cerebrospinal fluid may be extracted from around the spine (see Lumbar puncture) to check that the seizure was not caused by meningitis (see Meningitis in children). Other tests, such as urine tests or throat swabs, may also be performed to look for a bacterial infection.
If your child has prolonged or recurrent febrile convulsions, he or she may need to be given anticonvulsant drugs. The doctor will prescribe antibiotics if a bacterial infection is present. Up to 1 in 3 children who have had a febrile convulsion will have another within a year. About 1 per cent of affected children will go on to develop epilepsy in later life.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.