Febrile Seizures – Causes, Symptoms, and Prevention

Key Takeaways

Febrile seizures are convulsions triggered by fever in young children, usually between 6 months and 5 years of age. According to the US Centers for Disease Control and Prevention (CDC), approximately 2%–5% of children experience a febrile seizure before age 5 (1). Although these episodes can be frightening, most are brief and do not cause lasting harm. However, a febrile seizure in a newborn requires urgent medical evaluation, as seizures in newborns may indicate a serious underlying condition.

This article explains what does a febrile seizure look like, the key warning signs, possible triggers, and practical ways to reduce risks and protect your child’s health.

What Is a Febrile Seizure?

A febrile seizure is a convulsion that may get triggered by a high fever, often from an infection. A febrile seizure fever can be alarming for a parent to witness (2).

Febrile seizures represent the response of a child’s brain to rising body temperature, usually on the very first day of a fever. Fortunately, in most cases, the seizure has no lasting effect. It does not create difficulties in learning or cause any underlying disorder. However, as a matter of caution, a doctor should be consulted immediately if a child has an episode of febrile seizure.

As a parent, you can help your child by keeping him/her safe during a seizure and by comforting them afterwards. Febrile seizure fever does not cause any cognitive problems, epilepsy, or brain damage in a child. In fact, children having febrile seizures have excellent prognosis for normal neuron functions.

How Common Are Febrile Seizures in Children?

Children who have a family history of febrile seizures are more likely to suffer from one. If your child has had a febrile seizure and is below 15 months of age, then there is a high likelihood of them experiencing another seizure in future. In 30% of the cases, children who have had one seizure will have another one, generally within the first 1-2 years of their life (3). Thankfully, most children stop having febrile seizures by the age of 5 years and above.

Types of Febrile Seizures

Febrile seizures are generally classified based on how long they last, whether they affect one or both sides of the body, and whether they occur more than once within 24 hours. They are commonly divided into two main types (4):

1. Simple Febrile Seizures

Simple febrile seizures are the most common type and usually last less than 15 minutes. They affect the body on both sides, occur only once within 24 hours, and typically do not cause lasting neurological problems.

2. Complex Febrile Seizures

Complex febrile seizures last 15 minutes or longer, affect only one side of the body, or occur more than once within 24 hours. They require prompt medical evaluation to rule out other causes and determine appropriate care.

Causes of Febrile Seizures in Children

Wondering what causes febrile seizures in infants? This disturbing incident usually happens with fevers where the temperature is higher than 102 degrees Fahrenheit. The seizures tend to occur during the first 24 hours of a fever, but not necessarily when a child’s fever is spiking upwards.

There aren’t any specific causes of febrile seizures in infants. Certain viruses cause fever leading to seizure. Some children’s developing brains can also react to high fevers by triggering a seizure.

It is rather rare for a febrile seizure to be caused by a bacterial infection and related fever. Viral infections such as various types of the flu that are often accompanied by high fever are mostly linked to febrile seizure (5).

There is a misplaced apprehension that certain vaccinations, such as the vaccine for diphtheria, tetanus and/or measles-mumps-rubella, increase the chances of febrile seizures (6). In truth, it is a low-grade fever that causes the seizure, not the vaccination as interpreted in general.

Signs and Symptoms of Febrile Seizure

The febrile fever symptoms can range from mild to severe and from staring to shaking or tightening of the muscles. A child having a febrile seizure is likely to (4):

• Have a fever higher than 100.4 F (38.0 C)
• Lose consciousness
• Roll their eyes and drool
• Have darker skin
• The seizure may last only a few seconds or even up to 15 minutes

A child with a febrile seizure may feel tired and sleepy after the seizure subsides. Their arms and legs may jerk and the seizure may last only for a few seconds or up to 15 minutes.

Recurring Febrile Seizures

The first recurrence after an initial febrile seizure usually occurs within a year. Factors that increase the risk of having a recurring febrile seizure include (7):

Young age

Most febrile seizures are common in children between 6 months and 5 years of age. The likelihood of a recurrence decreases as the child grows up.

Family history

Some febrile seizures can be genetic in nature.

Persistent fever

A relatively shorter duration of low fever can also trigger febrile seizures.

Illness

As per medical reports, thirty per cent of children can have recurrent febrile seizures during subsequent illnesses.

Febrile Seizure Complications

The most common complication of a febrile seizure is the risk of recurrence. It can occur if (8):

• The first seizure resulted from a low fever.
• The period between the start of the fever and the seizure was short (a few hours).
• The child was very young at the time of the first febrile seizure (younger than 12 months).
• It is important to note any possible complications of febrile seizures as they could also be associated with a higher risk of recurrence.
• The three characteristics of febrile seizures where you must be careful are:
  1. when the seizure is focal, i.e., involves more than one part of the body.
  2. when the child suffers from multiple seizures, i.e., the seizure recurs within 24 hours.
  3. when the seizures are prolonged, i.e., last longer than 15 minutes.

Diagnosis of Febrile Seizure

The diagnosis involves a thorough physical examination, including a neurological exam or laboratory tests, if needed. The doctor will also track the history of symptoms.

Blood/urine tests and lumbar punctures are done to rule out other possible causes for the seizure and to detect viruses or bacteria or high levels of white blood cells, which may indicate infection. Dehydration (e.g., caused by vomiting and/or diarrhoea) and meningitis-related fever can also cause seizures.

Complex febrile seizures may require extensive diagnostic testing. Inconclusive lab tests, inconclusive physical examination, and any unusual suspicion of a neurological condition may make the doctor ask further questions. An electroencephalogram (EEG) is one such additional non-invasive test and is normally performed after a febrile seizure (9).

Further testing may not be needed in the following cases:

• If the child shows normal mental development
• The results of the neurological examinations are normal
• The seizure is general, not focal
• The seizure does not last longer than 15 minutes
• The seizure does not recur within 24 hours

Febrile Seizure Treatment

Most febrile seizures stop on their own within a couple of minutes. If your child’s seizures extend beyond a few minutes or repeat frequently, then it is advisable to call for emergency medical attention.

If the seizure is because of a persistent infection or if it is hard to determine the source of the infection, then your child may need hospitalisation for further observation.

How to Manage Febrile Seizure?

Parents need to take certain precautions to handle the situation while the child is having a febrile seizure (10).

• The child should be rolled on to their side to prevent choking.
• Never insert anything into their mouth.
• The movement of the convulsions or twitching should not be restricted.
• Any sharp items and objects should be removed as they may harm them during the seizure.
• Do not put your child in the water in an attempt to cool off the fever.

The understanding and reassurance of the family play a vital role in managing febrile seizure. A first seizure episode can be a terrifying experience for most parents. It is important to understand that there will be no subsequent risk of intellectual delay in the child.

The next step is to follow instructions for the treatment of a complex febrile seizure (if there is any) to rule out serious underlying infections such as meningitis or encephalitis. This will be done by lumbar puncture, clinical assessment, or through laboratory tests like EEG or neuroimaging. Your doctor will perform proper diagnosis and recommend the necessary treatment in case a serious illness is detected.

How to Prevent Febrile Seizures in Children?

Most febrile seizures occur in the first few hours of fever, during the initial rise in body temperature. In such a case, the child can be given paracetamol or acetaminophen for comfort. However, it must be remembered that these won’t stop a seizure.

Rarely, prescription anticonvulsant medications may be used to try to prevent febrile seizures. However, since these medications can have side-effects, they should be avoided unless necessary.

The paediatrician may prescribe specific drugs to treat a child having recurring febrile seizures or seizures of long duration.

When to Seek Medical Help

Seek immediate medical attention if your child experiences any of the following warning signs (8):

Despite the typically benign nature of febrile seizures, this condition should not be overlooked. The guidelines given here aim to help improve the understanding in dealing with febrile seizures and to ensure the overall health and wellness of the child.

Also Read:

Dengue Fever in Kids
Recurrent Fever in Children
Rheumatic Fever in Children

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Sources References

1. US Centers for Disease Control and Prevention – Febrile Seizures and Vaccines

2. Mayo Clinic – Febrile seizure

3. National Library of Medicine – Febrile Seizure

4. Cleveland Clinic – Febrile Seizure

5. PubMed Central – The Pathogenesis of Fever-Induced Febrile Seizures and Its Current State

6. American Academy of Pediatrics – Febrile Seizures in Children

7. PubMed Central – Etiological and risk factors in recurrent febrile seizures: Insights through EEG analysis

8. NHS inform – Febrile seizures

9. Mayo Clinic – EEG (electroencephalogram)

10. Nemours KidsHealth – Febrile Seizures