What Are Febrile Seizures? What Are Febrile Convulsions? What Causes Febrile Seizures?

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Main Category: Pediatrics / Children's Health
Also Included In: Infectious Diseases / Bacteria / Viruses
Article Date: 20 Oct 2009 - 5:00 PST

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A febrile seizure, or febrile convulsion, is a convulsion which can occur in young children when their body temperature suddenly rises, usually as a result of infection or inflammation. Febrile seizures most commonly affect children and babies aged 6 months to 5 years, and especially those aged between 6 months and 3 years.

In this article the term convulsion is used as a synonym for seizure. It is important to bear in mind that in some other articles their meanings might not be exactly the same (not all seizures are characterized by convulsions).

For parents, to witness their small child having a febrile seizure it can be distressing. Even though most seizures only last a few minutes, for the parents it can feel like much longer.

Experts say that febrile seizures are nowhere near as dangerous as they appear to be. In the majority of cases a seizure that is caused by a sudden spike in temperature is harmless and does not suggest that there is a long-term medical problem.

Sometimes a febrile seizure can come on even before the parents know that the child is ill.

Pediatricians and GPs (general practitioners, primary care physicians) say that even though febrile seizures are not common, they are not that rare either.

There are two types of febrile seizures:

Simple febrile seizures - the seizure lasts less than 15 minutes and does not occur again during the infection.

Complex febrile seizure - there are several episodes of seizures during the infection. Convulsions may last longer than 15 minutes.

About three-quarters of all febrile seizures are simple febrile seizures.

According to Medilexicon's medical dictionary:

a febrile convulsion is "a brief seizure, lasting less than 15 minutes, seen in a neurologically normal infant or young child, associated with fever."

a complex febrile convulsion is "a febrile convulsion that is prolonged (longer than 15 minutes' duration) or is associated with focal neurologic deficits."

What are the causes of febrile seizures?

The majority of febrile seizures occur because the child's body temperature suddenly rises. The seizure occurs mostly during the first day of the fever. However, occasionally the seizure may develop as the elevated body temperature is coming down.

The following childhood infections may increase a child's risk experiencing febrile seizures:

• Gastroenteritis (stomach or intestinal infection)
• Kidney infection
• Lower respiratory tract infection, this may include pneumonia
• Middle-ear infection (otitis media)
• Some viral infections, such as flu (influenza) or chicken pox
• Tonsillitis
• Urinary tract infection
• Infection of the child's central nervous system (brain and spinal cord), such as encephalitis or meningitis (much less common but very serious)

Vaccinations

Although the risk of having febrile seizures after vaccination is very small, it does exist. According to some studies, 25 to 34 children out of every 100,000 who have the MMR (measles, mumps and rubella) vaccine subsequently have febrile seizures.

The anti diphtheria, whooping cough, tetanus, polio and hemophilus influenza type b vaccine (DTaP/IPV/Hib) has an even lower risk than the MMR.

Doctors say that even if a child has had febrile seizures after taking vaccinations, he/she should still complete the vaccination schedule. The risk of catching those diseases and developing complications related to them are far greater.

Experts believe that the febrile seizure that occurs soon after a vaccination is caused by the fever itself, rather than the vaccination.

What are the risk factors for febrile seizures?

A risk factor is something that makes a condition or illness more likely. For example, smoking is linked to a higher risk of developing lung cancer. Therefore, smoking is a risk factor for lung factor. The risk factors for febrile seizures are:

• Age - children under the age of five are much more likely to have a febrile seizure than older people. Approximately 4% of all children have a febrile seizure. The most likely age is between 6 months to 3 years.


• Family history - if either or both parents had febrile seizures when they were babies, there is a greater chance that their young offspring will do so too.

What are the signs and symptoms febrile seizures?

A symptom is something the patient reports and feels, while a sign is something other people, including a doctor may detect. For example, a headache may be a symptom while a rash may be a sign.

The signs and symptoms of febrile seizures are similar to those found in epileptic seizures, called tonic-clinic seizures. Even though symptoms may seem similar to those of epilepsy, it does not mean that the child has epilepsy - febrile seizure occurrences are not closely linked to epilepsy risk.

In most cases a febrile seizure occurs on the first day of the child's fever, fairly close to the onset of the fever. That is why parents may witness a seizure before they realize the child has a temperature (before they realize he/she is ill). Parents often feel guilty about not noticing that the child was poorly, but they should not blame themselves for this, as it is common.

During a febrile seizure:

• The child's body becomes stiff
• Arms and legs start to twitch, shake or jerk on both sides of the body
• They may have trouble breathing
• They will lose consciousness
• They may wet themselves
• They may soil themselves
• They may vomit
• They may foam at the mouth
• Their eyes may roll back in the head
• They may cry or moan

In most cases the seizure lasts only a few minutes. When it is over the child may seem sleepy for up to an hour.

Complex febrile seizures - if the child has complex febrile seizures, each one may last longer, perhaps for more than 15 minutes. There may be several seizures while the child has the infection and an elevated body temperature. The child may twitch on only one side of the body - this is known as a focal seizure.

Even though a fever triggers a febrile seizure, the severity of signs and symptoms are not necessarily linked to the severity of the fever.

How are febrile seizures diagnosed?

The GP (general practitioner, primary care physician) or pediatrician will examine the patient and try to find out what has caused the fever and seizure.

Blood and urine tests will be ordered to find out whether there is an infection, and what type of infection it is. If the child is very young it may be difficult to get a urine sample, and obtaining it may have to take place in hospital.

If the physician suspects that the brain and spinal cord (nervous system) is infected a spinal tap (lumbar puncture) may be ordered. The child is given a local anesthetic, and then the doctor inserts a needle into his/her lower back to remove a small amount of spinal fluid. This test can determine whether there is any infection in the fluid that surrounds the brain and spinal cord.

If the child has a complex febrile seizure the doctor may order some further tests.

What are the treatment options for febrile seizures?

Any child who has a febrile seizure should first be placed in the recovery position. Place the child on their side with their face turned to one side. Try to find a soft surface to lay them onto. This position will prevent them from swallowing vomit; it will also keep their airways open, and will help prevent injury. Stay with the child and try to time the seizure. If it lasts less than five minutes call your GP. If it lasts longer call for an ambulance - even though the child is likely to have nothing serious, it is a sensible precaution.

If the seizure continues until the child arrives at the emergency room, a hospital doctor may administer medication through the child's rectum or intravenously to stop the seizure. Seizures rarely last long enough for this to be necessary.

If the seizure is particularly long, the infection appears to be a serious one, or doctors don't know what is causing it, the medical team may want the child to stay in the hospital for observation.

Do not put anything into the child's mouth during the seizure. You may be concerned they may bite their tongue - even if they do, in the vast majority of cases the injury is not serious and heals quickly. Trying to stop a person with a seizure from biting their tongue may place both the patient and you in danger.

Treatment for a fever

Acetaminophen (paracetamol), as well as ibuprofen may help lower the symptoms of fever. Make sure the doses are for young children; if you are not sure talk to a qualified pharmacist. Children under the age of 16 years should not take aspirin. Make sure the child has loose clothing, do not overdress them or wrap them up in too much bedding.

Treating recurring febrile seizures

About 1 in 3 children will have febrile seizures later on when they have another infection and a spike in body temperature, usually within twelve months after a seizure. Recurring febrile seizures are more common among:

• Children whose first febrile seizure happened when they were less than 18 months of age.
• Children whose first seizure was a complex febrile seizure.
• There is a family history of seizures.
• There is a family history of epilepsy.
• The child attends a day nursery, where more childhood infections are likely.

Generally, the adverse effects of using medications to prevent subsequent febrile seizures are greater than the risk of getting further seizures; therefore they are not usually recommended. If the child is exceptionally prone to getting seizures when they have a fever, medication might be prescribed. At the start of a fever, such a child might benefit from taking diazepam.

What are the possible complications of febrile seizures?

It must be stressed that although seizures appear alarming and may distress parents, in the vast majority of cases there are no lasting effects or complications. A simple febrile seizure does not cause brain or neurological damage, learning disabilities, any kind of mental retardation, or any underlying disorder.

Recurrent febrile seizures - approximately 1 in 3 children who have a febrile seizure have further febrile seizures the next time they have a fever. The risk of recurrence is higher if:

• A close family member has a history of febrile seizures.
• The first febrile fever occurred when the child was very young (still a baby or young toddler).
• The first febrile seizure coincided with a low fever.
• The first febrile seizure occurred very soon after the fever started.

Epilepsy

The risk of developing epilepsy after having a febrile seizure is considered as small. According to the National Health Service (NHS), UK, the chances of developing epilepsy after a simple febrile seizure are 1.5%. If the child was under 12 months of age during his/her first febrile seizure (and experienced multiple simple seizures) the risk is 2.5%.

Each of the following factors also increases the risk of developing epilepsy:

• A developmental delay before febrile seizures started
• A family history of epilepsy
• Complex seizures
• Neurological abnormalities
• The seizure occurred within an hour of the onset of fever

Written by Christian Nordqvist
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today