Occasionally, a baby with a high, or very high temperature will experience a fit or a seizure. This is known medically as a 'febrile convulsion'. Fits due to a fever can happen for up to 5 % of all children, but they are rare in babies under 6 months of age.
A fit can occur because the baby's brain is immature, and therefore sensitive to high increases in body temperature. Their brain responds by giving off an abnormal electrical discharge, causing a fit (or convulsion). A baby's brain can respond with a similar reaction if they consume certain poisons or have an infection of their brain, known as 'meningitis' or 'encephalitis'. They can also fit if they sustain some form of brain injury, as this can also disrupt the electrical impulses in their brain.
When a baby fits, they lose consciousness and their body twitches all over. A fit can last up to 5 minutes, although if this is happening to your baby it will feel like an eternity. It is extremely frightening and distressing to watch your baby fit. Try not to panic and keep calm (obviously easer said than done!) and stay with your baby. If possible, loosen any clothes around their neck and strip them down, or take off any heavy clothing. To stop your baby from hurting themselves, gently place your baby on a soft surface and on their side (or tummy with their head to one side) and gently support their head with your hands. Do not restrain your baby (or hold them tightly) and never put anything into their mouth, or force their mouth open. Never put your baby into a bath while they are fitting.
If your baby has a fit (or febrile convulsion) due to a fever, it will not cause brain damage, even though the fit is very dramatic and frightening. After the fit passes, seek urgent medical advice, or go to your nearest children's hospital as soon as possible. The doctors may want to perform some tests, depending on the age of your baby, and the length of the fit.