Febrile Convulsions (3 months to 5 years)
Febrile convulsions or seizures are the most common seizures of early childhood. The average age of onset is 18 to 22 months. These seizures are also common in children between the ages of 3 months to 5 years and rarely occur after that.
Febrile seizures are often the first sign of illness and tend to occur on the first day of the illness. They may also occur following immunization, appearing a few days after the infant has been immunized.
Each of us will have a seizure if our temperature rises high enough. However, the threshold in children under age 5 or 6 is naturally lower, increasing their susceptibility to febrile convulsions. Although febrile convulsions can affect any child, they tend to run in families. There also appears to be a higher incidence in boys.
Symptoms
The most common febrile seizures are tonic-clonic (grand mal) or tonic (stiffening of limbs and body), but any seizure type is possible. The seizures in most infants will last less than six minutes, although the episodes can range from one or two minutes to more than 15 minutes. About 16 percent of infants who have a first febrile seizure will experience a second seizure within 24 hours.
The following are some of the symptoms that might occur as fever seizures :
- A cry, loss of consciousness and muscle rigidity
- Staring and muscle stiffness
- Staring and loss of muscle tone or limpness
- Rhythmic jerking movements involving both sides
- Jerking, stiffening, or limpness involving one side
About 8 percent of children with fever seizures will have seizures lasting 15 minutes or more. Seizures lasting this long require immediate medical attention, as prolonged or non-stop seizures can lead to potential neurological impairment.
Evaluation
Febrile Convulsions / Fever Seizures
Elevated temperature is the hallmark of febrile convulsions. The initial step in evaluation will be to identify the source of the fever. The doctor will examine the infant for a possible ear or throat infection or other signs of illness. Limited blood tests and urinalysis may be conducted. Brain imaging and EEG brain-wave analysis have limited value in assessing febrile convulsions and may not be used.
If results are negative, a spinal fluid sample will likely be analyzed for signs of brain infection. Brain infections are rare but serious complications that can lead to potential neurological damage, epilepsy and other impairments. Seizures due to brain infection are not classified as febrile convulsions and require immediate therapy.
The child who experiences a first febrile convulsion will likely be held for several hours in the emergency room or doctor’s office for observation. A child who is alert and active during this period may be returned home , whereas further observation in the hospital may be prescribed for the child who has a second seizure or shows signs of lethargy or weakness.
Treatment
Febrile Convulsions / Fever Seizures
A first febrile convulsion that stops within a few minutes without anticonvulsant medication may not need to be treated. However, another type of medication may be administered to lower the fever and make the child more comfortable.
In most cases physicians do not prescribe long-term use of anticonvulsants to prevent future febrile convulsions because of the potential side effects and questionable effectiveness . A doctor may sometimes decide that medication given only while the child has a fever may be the best alternative. Physicians may recommend that children especially prone to febrile seizures be treated with diazepam— given either orally or rectally— when they have a fever.
Outcome
Febrile Seizures / Fever Seizures
Three to 4 percent of all children experience at least one febrile seizure. Thirty to 40 percent of those who have these seizures will have a recurrence, however, the vast majority outgrow febrile convulsions by the age of 5 and develop normally. Relatively few will go on to develop epilepsy.
Seizure recurrence risk
Only 9 percent of children have three or more febrile convulsions. The risk of seizure recurrence is highest under the following conditions:
- First seizure occurs before the age of 18 months
- Seizure occurs within first hours of an illness
- Fever is only moderate (101-102 degrees)
- History of febrile seizures in the immediate family
Epilepsy risk
Factors that increase the risk for later development of epilepsy are :
- Febrile seizure lasting more than 15 minutes
- Partial or focal febrile seizure (occurs only on one side)
- Two or more febrile seizures in 24 hours
- Developmental delay
- Cerebral palsy, mental retardation or other neurological disorder
- Family history of epilepsy