A child's first febrile convulsion is a completely unexpected and often very dramatic event for parents, with many fearing for their child's life. However, the prognosis for repeated febrile convulsions is very good. The child's further development is unaffected. Only in a few cases can febrile seizures be the first sign of the onset of epilepsy.
As a febrile seizure can in rare cases also be the first symptom of men ingitis (meningoencephalitis), a first febrile seizure should always be immediately presented to a doctor and a lumbar puncture (examination of the cerebrospinal fluid) should be generously indicated, especially in infants and small children.
A febrile seizure is a seizure that occurs at a high temperature in children between 3 months and 5 years of age. It is important to note that it is not usually a manifestation of epilepsy and that no intercranial infection or other defined cerebral cause is the reason for the seizure.
Febrile seizures generally occur in children who already have a lower seizure threshold due to their constitution. This is lowered even further by the fever, resulting in a tonic-clonic seizure. Febrile convulsions are therefore classed as occasional convulsions and are the most common type of occasional convulsion, accounting for around 50 percent of all convulsions.
A febrile convulsion usually occurs initially at the beginning of the infection during the first rise in temperature. The most common clinical form of seizure is the generalized tonic-clonic seizure. This causes stiffness throughout the body and twitching of the arms and legs. The children are unresponsive in this phase, although their eyes are open. Depending on the duration of the seizure, children may also develop a blue coloration of the face (cyanosis).
The seizures are usually short (< 3 min), stop on their own and only occur once within 24 hours. After the seizure, children are often tearful and tired and fall asleep quickly.
The distinction between a simple and a complicated febrile convulsion is important for the diagnosis and the resulting therapeutic measures:
Simple febrile convulsion:
- the seizure corresponds to a tonic-clonic seizure
- Duration of the seizure < 15 min
- Only one seizure occurs within 24 hours
- The child is tired after the seizure but shows no motor abnormalities
Complicated febrile seizure (with at least 1 symptom):
- the seizure corresponds to a focal seizure
- Duration of the seizure > 15 min
- More than 1 seizure within 24 hours
- Age of the child < 6 months or > 5 years
- After the seizure, the child shows temporary symptoms such as paralysis
The general risk of recurrence for febrile convulsions is approx. 30 percent, for a febrile convulsion in the first year of life 50 percent.
Children with febrile convulsions have a 95% good prognosis with completely normal development, even if simple febrile convulsions occur repeatedly.
The later risk of epilepsy for children increases only slightly after simple febrile convulsions:
- Risk of epilepsy (prevalence in the general population: 1 percent)
- 1 to 2 percent of children after uncomplicated febrile convulsion
- 10'to 15 percent of children after complicated febrile convulsion
General measures:
- Keep calm, bed the child so that it cannot injure itself (especially the head).
- Look at a watch to assess the length of the seizure.
- In the event of a first febrile convulsion, the emergency doctor should be called.
Most febrile convulsions end spontaneously within 2 to 3 minutes. From a duration of 5 minutes, the seizure should be interrupted with the help of a fast-acting, orally or rectally administered emergency medication, which is prescribed to children after a first febrile convulsion. Long-term drug therapy is not usually necessary.
As febrile convulsions usually occur during the first rapid rise in temperature of an infection, they cannot usually be prevented by consistently lowering the temperature. Parents should be informed accordingly, as antipyretic medication is often recommended from a body temperature of 38.5°C.