What is it?
- A febrile seizure is a convulsion in young children that may be caused by a sudden spike in body temperature, often from an infection. Watching your child experience a febrile seizure can be alarming. And, although a febrile seizure may last only a few minutes, it may seem like an eternity to you.
- Fortunately, febrile seizures aren't as dangerous as they may look. A seizure triggered by a fever is usually harmless and typically doesn't indicate a long-term or ongoing problem.
- You may feel helpless during a febrile seizure, but you can make sure your child is safe during a seizure and offer comfort afterward. Following up with a doctor's visit is another good approach for handling a febrile seizure.
Febrile seizure symptoms can range from mild — rolling of the eyes — to more severe shaking or tightening of the muscles.
A child having a febrile seizure may:
- Have a fever usually higher than 102 F (38.9 C)
- Lose consciousness
- Shake or jerk the arms and legs on both sides of the body
- Roll his or her eyes back in the head
- Have trouble breathing
Febrile seizures are classified as simple or complex:
- Simple febrile seizures. These are the most common type of febrile seizure, and they can last from a few seconds to 10 minutes and stop on their own.
- Complex febrile seizures. A complex febrile seizure lasts longer than 15 minutes, occurs more than once within 24 hours or is confined to one side of your child's body.
Although a febrile seizure is usually caused by a rapid rise in your child's temperature, it can also occur when the fever is on its way down. And, the severity of the signs and symptoms doesn't necessarily reflect the level of the fever.
Most febrile seizures occur because of a sudden spike in body temperature, and most occur during the first day of a fever. But a febrile seizure may also develop as the fever is declining.
Viral or bacterial infection
Usually, the fevers that trigger febrile seizures are caused by an infection in your child's body. Typical childhood illnesses, including viral infections such as roseola — a viral illness that causes swollen lymph nodes, usually in the neck, and a rash — are often associated with febrile seizures. A less common but very serious cause of sudden fever with seizures is an infection of a child's brain and spinal cord (central nervous system), such as meningitis or encephalitis.
The risk of febrile seizures may increase after some childhood immunizations. Febrile seizures may rarely occur eight to 14 days after a measles-mumps-rubella (MMR) vaccination. Low-grade fevers can sometimes occur after your child receives childhood vaccines. If a febrile seizure occurs, it's caused by the fever that may accompany the vaccination — not by the vaccination itself.
Several risk factors have been identified that increase your child's likelihood of experiencing a febrile seizure. These include:
- Age. Young age is the strongest risk factor, and most febrile seizures are seen in children who are between 6 months and 5 years of age. It's unusual for children under 6 months old to have a febrile seizure, and it's rare for these seizures to occur after 3 years of age. About 1 in 25 children experience a febrile seizure.
- Family history. Some children inherit a family's tendency to have seizures with a fever. Additionally, researchers have linked several genes to a susceptibility to febrile seizures.
Although febrile seizures may cause great fear and concern for parents, most febrile seizures produce no lasting effects. Simple febrile seizures don't cause brain damage, mental retardation or learning disabilities, and they don't mean your child has a more serious underlying disorder.
Febrile seizures also aren't an indication of epilepsy, a tendency to have recurrent seizures caused by abnormal electrical signals in the brain. The odds that your child will develop epilepsy after a febrile seizure are small. Only a small percentage of children who have a febrile seizure go on to develop epilepsy, but not because of the febrile seizures.
Recurrent febrile seizures
The most common complication of febrile seizures is the possibility of more febrile seizures. About a third of children who have a febrile seizure will have another one with a subsequent fever.
The risk of recurrence is higher if:
- Your child had a low fever at the time of the first febrile seizure.
- The period between the start of the fever and the seizure was short.
- An immediate family member has a history of febrile seizures.
- Your child was younger than 15 months old at the time of the first febrile seizure.
After experiencing a febrile seizure, your child will likely have:
- A physical exam
- Blood tests
- Urine tests
These tests can help determine possible causes of the fever and seizure.
If your doctor suspects a central nervous system infection, a lumbar puncture (spinal tap) may be necessary. In this procedure, a doctor inserts a needle into your child's lower back to remove a small amount of spinal fluid. This test can reveal evidence of infection in the fluid that surrounds the brain and spinal cord.
Further tests such as an electroencephalogram (EEG) — a test that measures brain activity — may be necessary if your child had a complex febrile seizure.
Treatments and drugs
It's not necessary to lower your child's fever to stop a febrile seizure. So don't try to give your child fever medications during a seizure. For the same reason, don't place your child in a cooling tub of water. It's much more practical, more comfortable — and safer — for your child to remain lying on the carpet or a bed.
Most febrile seizures stop on their own within a couple of minutes. If your child has a febrile seizure that lasts more than five minutes — or if your child has repeated seizures — call for emergency medical attention.
In rare cases, the seizure may continue until your child receives treatment at the emergency room. If this happens, a doctor may order medication that's administered either through your child's rectum or intravenously to stop the seizure.
If the seizure is prolonged or accompanied by a serious infection or if the source of the infection can't be determined, your doctor may want your child to stay in the hospital for further observation. But a hospital stay isn't routinely necessary for simple febrile seizures.
If your child has a febrile seizure, stay calm and follow these steps to help your child during the seizure:
- Place your child on his or her side, somewhere where he or she won't fall.
- Stay close to watch and comfort your child.
- Remove any hard or sharp objects near your child.
- Loosen any tight or restrictive clothing.
- Don't restrain your child or interfere with your child's movements.
- Don't attempt to put anything in your child's mouth.
If possible, try to time the seizure using your watch or a clock. Because they're so alarming, seizures often seem to last longer than they really do. Also try to note which part of your child's body begins to shake first, and look for other signs of illness. This can help your doctor understand the cause of the seizure.
Not long after having a febrile seizure, many children are back on their feet, running around the doctor's office or playing safely at home. By staying calm, observing your child and knowing when to call the doctor, you're doing everything that's needed to take care of your child.
Most of the time, a febrile seizure occurs the first day of an illness. Often, a febrile seizure occurs before parents realize that their child is ill.
Giving your child medications
Giving your child acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin, others) at the first indication of fever will help reduce the fever, but won't necessarily prevent a seizure. And, there are some caveats to giving medications to young children. Medications won't shorten the course of infection, and low-grade fevers generally don't need treatment.
Additionally, there's always a question of safety when giving medications to young children. For example, aspirin may trigger a rare but potentially fatal disorder known as Reye's syndrome. And, while acetaminophen is generally safe, if you give a child too much, it can cause liver failure. Ask your doctor what medications he or she recommends and what the proper dosage is for your child's age and weight.
Making sure your child drinks plenty of fluids and is appropriately dressed — not overdressed — may help control the fever.
Prescription prevention medications
Rarely, prescription medications are used to prevent febrile seizures. Anticonvulsant medications such as phenobarbital, valproic acid (Depakene) and divalproex sodium (Depakote) can prevent febrile seizures when taken daily. Oral or rectal diazepam (Valium, Diastat) also can reduce the risk of febrile seizures if taken at the time of a fever.
But these medications all have drawbacks. They carry a definite risk of serious side effects in young children, such as sleep problems, irritability and hyperactivity. Doctors rarely prescribe these prevention medications because most febrile seizures are harmless and most children outgrow them without any problems.