7 Key Symptoms of Febrile Seizure: What Parents Need to Know

A febrile seizure is a convulsion that occurs in young children, typically between the ages of 6 months and 5 years, triggered by a sudden spike in body temperature. These seizures can be frightening for parents to witness, but they are usually harmless and don’t indicate a serious underlying condition. Febrile seizures affect approximately 2-5% of children and are most commonly associated with viral infections, ear infections, or post-vaccination fever.

Understanding the symptoms of febrile seizures is crucial for parents and caregivers to respond appropriately during an episode. While most febrile seizures are brief and resolve on their own, recognizing the signs can help you stay calm and ensure your child receives proper care if needed. This comprehensive guide will walk you through the key symptoms, causes, and frequently asked questions about febrile seizures.

1. Sudden Loss of Consciousness

One of the most alarming symptoms of a febrile seizure is the sudden loss of consciousness. Your child may appear awake and responsive one moment, then suddenly become unresponsive the next. During this state, they will not react to your voice, touch, or other stimuli.

This loss of consciousness typically occurs abruptly at the onset of the seizure and can last anywhere from a few seconds to several minutes. The child’s eyes may remain open, but they will not make eye contact or show awareness of their surroundings. This symptom can be particularly distressing for parents, but it’s important to remember that consciousness usually returns shortly after the seizure ends.

What to observe:

• Complete unresponsiveness to verbal commands
• No reaction to physical touch or stimulation
• Blank stare or unfocused eyes
• Duration typically ranges from 30 seconds to 15 minutes

2. Rhythmic Jerking Movements

Rhythmic jerking or twitching movements of the arms, legs, or entire body are hallmark symptoms of a febrile seizure. These movements are involuntary and cannot be controlled or stopped by the child. The jerking typically follows a regular pattern and affects both sides of the body symmetrically.

During a generalized febrile seizure, which is the most common type, the jerking movements will affect the entire body. The arms and legs may shake or twitch in a coordinated rhythm. These movements can vary in intensity from subtle twitches to more pronounced convulsions. The muscles alternate between contracting and relaxing, creating the characteristic jerking motion.

Characteristics of jerking movements:

• Bilateral involvement (affecting both sides of the body)
• Rhythmic and repetitive pattern
• Involuntary and cannot be restrained
• May involve the face, causing jaw clenching or facial twitching
• Typically lasts for 1-2 minutes but can extend up to 15 minutes

3. Body Stiffening and Muscle Rigidity

Before or during the jerking phase, many children experience a tonic phase characterized by sudden muscle stiffening and rigidity. The child’s body may become completely rigid, with their back arched and limbs extended or flexed in a fixed position. This stiffening usually occurs at the very beginning of the seizure.

During this phase, the entire body may become tense and rigid, making the child appear frozen in position. The muscles contract forcefully and continuously, which is different from the alternating contractions seen in the jerking phase. This rigidity can affect breathing temporarily, which may cause the child’s skin to take on a bluish tint due to reduced oxygen.

Signs of muscle stiffening:

• Sudden tensing of the entire body
• Arched back or extended neck
• Clenched fists and tightened jaw
• Rigid posture lasting 10-20 seconds before jerking begins
• Difficulty breathing during the stiffening phase

4. Eye Rolling or Abnormal Eye Movements

Abnormal eye movements are a common and often disturbing symptom of febrile seizures. Parents frequently report that their child’s eyes “rolled back” into their head, showing only the whites of the eyes. Alternatively, the eyes may deviate to one side or move in unusual patterns.

These eye movements occur because the seizure affects the muscles that control eye movement. The eyes may roll upward, to the side, or flutter rapidly. Sometimes the eyelids may remain open throughout the seizure, while in other cases they may flutter or partially close. After the seizure, the child’s eyes typically return to a normal position, though they may appear glazed or unfocused during the post-seizure recovery period.

Types of eye involvement:

• Upward deviation of the eyes (rolling back)
• Fixed gaze to one side
• Rapid, involuntary eye movements (nystagmus)
• Fluttering eyelids
• Dilated pupils that may not respond normally to light

5. Changes in Breathing Patterns

Irregular breathing is a symptom that causes significant concern for parents witnessing a febrile seizure. During the seizure, a child’s normal breathing rhythm may be disrupted, becoming shallow, irregular, or temporarily stopped. This happens because the seizure affects the muscles involved in respiration.

The breathing changes are usually most pronounced during the initial tonic (stiffening) phase of the seizure. Parents may notice their child holding their breath, breathing very rapidly, or making unusual sounds such as grunting or gasping. In some cases, the disrupted breathing may cause cyanosis, a bluish discoloration of the lips, face, or fingernails due to reduced oxygen in the blood.

Breathing pattern changes:

• Temporary cessation of breathing (apnea) lasting several seconds
• Shallow or irregular breathing rhythm
• Rapid breathing (tachypnea)
• Bluish tint to lips or skin (cyanosis)
• Breathing typically normalizes within 1-2 minutes after seizure ends
• Possible foam or saliva at the mouth

6. High Fever

A high fever is the defining trigger of a febrile seizure, though parents may not always be aware that their child has a fever before the seizure occurs. The seizure is typically associated with a body temperature of 100.4°F (38°C) or higher, though it often occurs with temperatures above 102°F (38.9°C).

Febrile seizures frequently occur during the rapid rise in temperature rather than when the fever has been sustained for a long period. This means that a seizure might be the first sign that your child has a fever. The fever itself is usually caused by an underlying infection, most commonly viral illnesses like the flu, roseola, or upper respiratory infections. Post-vaccination fevers can also trigger febrile seizures in susceptible children.

Fever characteristics:

• Temperature typically 100.4°F (38°C) or higher
• Seizure often occurs during rapid temperature rise
• May be the first indication that the child is ill
• Usually caused by viral infections
• Can occur with ear infections, throat infections, or post-vaccination
• Child may feel hot to the touch and appear flushed

7. Post-Seizure Drowsiness and Confusion

After a febrile seizure ends, children typically enter what is called the postictal state, characterized by drowsiness, confusion, and lethargy. This recovery phase is a normal part of the seizure process and indicates that the brain is recovering from the seizure activity.

During this phase, which can last from a few minutes to several hours, your child may seem extremely tired and want to sleep. They might be confused, disoriented, or not recognize familiar people or surroundings temporarily. Some children may be irritable or cry when they regain consciousness. Physical weakness or clumsiness is also common during this recovery period.

Postictal symptoms include:

• Extreme sleepiness or desire to sleep
• Confusion or disorientation lasting minutes to hours
• Temporary memory loss about the seizure event
• Irritability or emotional upset
• Headache or general malaise
• Weakness on one side of the body (less common)
• Gradual return to normal alertness and behavior

Main Causes of Febrile Seizures

Febrile seizures are caused by a combination of genetic predisposition and environmental triggers. Understanding these causes can help parents identify risk factors and potentially prevent future episodes.

Primary causes include:

Rapid Temperature Elevation

The most immediate cause is a sudden spike in body temperature. It’s the rate of temperature rise rather than the peak temperature that often triggers the seizure. This explains why febrile seizures sometimes occur early in an illness when fever is just beginning.

Viral Infections

Most febrile seizures are triggered by common viral infections including:

• Human herpesvirus 6 (HHV-6), which causes roseola
• Influenza (flu virus)
• Adenovirus
• Respiratory syncytial virus (RSV)
• Common cold viruses

Bacterial Infections

Though less common than viral causes, bacterial infections can also trigger febrile seizures:

• Ear infections (otitis media)
• Urinary tract infections
• Strep throat
• Pneumonia

Genetic Predisposition

Children with a family history of febrile seizures are at higher risk. If a parent or sibling had febrile seizures, the child has a 10-20% increased likelihood of experiencing them. Research suggests that several genes may influence susceptibility to febrile seizures.

Age and Developmental Factors

The immature brain of young children is more susceptible to seizures triggered by fever. The majority of febrile seizures occur between 12 and 18 months of age, when the brain is still developing its temperature regulation and seizure threshold mechanisms.

Post-Immunization Fever

Some children develop febrile seizures following vaccinations, particularly after the MMR (measles, mumps, rubella) vaccine or DTaP (diphtheria, tetanus, pertussis) vaccine. This occurs because vaccines can cause fever as part of the normal immune response.

Prevention Strategies

While it’s not always possible to prevent febrile seizures, there are several strategies parents can implement to reduce the risk of recurrence and manage fever effectively.

Fever Management

Prompt management of fever is the cornerstone of prevention:

• Monitor your child’s temperature regularly during illness
• Keep your child comfortable and well-hydrated
• Use fever-reducing measures such as lightweight clothing and room temperature baths
• Consult with your pediatrician about appropriate fever management for your child

Important note: While managing fever is sensible, studies show that aggressive fever reduction with medications doesn’t necessarily prevent febrile seizures, as they often occur during the initial temperature rise before parents are aware of the fever.

Education and Preparedness

Being prepared can help you respond effectively if a seizure occurs:

• Learn what to do during a seizure (stay calm, place child on side, time the seizure)
• Educate family members and caregivers about febrile seizures
• Keep emergency numbers readily available
• Know when to call for emergency help (seizures lasting over 5 minutes, difficulty breathing after seizure, or multiple seizures)

Monitoring During Illness

Children who have had one febrile seizure are at increased risk for another, particularly during the next fever-causing illness:

• Pay close attention during illnesses, especially in the first 24 hours
• Monitor for signs of infection early
• Seek medical attention promptly for concerning symptoms
• Inform your pediatrician about your child’s history of febrile seizures

Genetic Counseling

If febrile seizures run in your family, discussing this with your healthcare provider can help you:

• Understand your child’s individual risk factors
• Develop a personalized management plan
• Know what to expect and when to be most vigilant

What Won’t Prevent Febrile Seizures

It’s equally important to understand what doesn’t work:

• Prophylactic medications are generally not recommended for simple febrile seizures due to potential side effects and limited effectiveness
• Aggressive fever reduction hasn’t been proven to prevent febrile seizures
• There’s no evidence that avoiding certain foods or activities prevents these seizures

Frequently Asked Questions

Are febrile seizures dangerous?

Simple febrile seizures are generally not dangerous and don’t cause brain damage, learning disabilities, or developmental delays. Most children who experience febrile seizures develop normally. However, prolonged seizures lasting more than 15 minutes (complex febrile seizures) require immediate medical attention.

Will my child have epilepsy if they have febrile seizures?

The vast majority of children who experience febrile seizures do not develop epilepsy. Only about 2-7% of children with simple febrile seizures later develop epilepsy, which is only slightly higher than the general population risk of 1-2%. The risk is higher if there are other risk factors present, such as a family history of epilepsy or complex febrile seizures.

At what age do children outgrow febrile seizures?

Most children outgrow febrile seizures by age 5, with the majority occurring between 12 and 18 months. Febrile seizures rarely occur for the first time after age 3, and they almost never occur after age 6 as the brain matures and becomes less susceptible to fever-triggered seizures.

What should I do during a febrile seizure?

During a febrile seizure, remain calm and take these steps: place your child on their side on a flat surface to prevent choking, remove any nearby objects that could cause injury, loosen tight clothing around the neck, time the seizure, and never put anything in the child’s mouth. After the seizure, comfort your child and seek medical advice.

How long do febrile seizures typically last?

Most febrile seizures last between 1-2 minutes, though they can feel much longer to frightened parents. Simple febrile seizures last less than 15 minutes. If a seizure continues for more than 5 minutes, call emergency services immediately, as this may indicate a more serious situation requiring medical intervention.

Can febrile seizures recur?

Yes, approximately one-third of children who have one febrile seizure will experience at least one more. The risk of recurrence is higher in children who had their first seizure before age 18 months, those with a family history of febrile seizures, children who had a lower fever with their first seizure, and those whose seizure occurred shortly after the fever began.

Should I take my child to the hospital after a febrile seizure?

For a first-time febrile seizure, it’s recommended to seek medical evaluation to rule out serious infections and confirm the diagnosis. For subsequent simple febrile seizures in a child with a known history, contact your pediatrician for guidance. Seek emergency care if the seizure lasts more than 5 minutes, occurs without fever, the child has difficulty breathing, has multiple seizures in 24 hours, or shows signs of serious illness such as stiff neck or severe lethargy.

Is there a difference between simple and complex febrile seizures?

Yes. Simple febrile seizures last less than 15 minutes, involve the entire body (generalized), and occur only once during a 24-hour period. Complex febrile seizures last longer than 15 minutes, may affect only one part of the body (focal), or occur more than once within 24 hours. Complex febrile seizures require more thorough medical evaluation and follow-up.

References:

• Mayo Clinic – Febrile Seizure
• Centers for Disease Control and Prevention – Febrile Seizures
• National Institute of Neurological Disorders and Stroke – Febrile Seizures
• NHS – Febrile Seizures
• American Academy of Pediatrics – Febrile Seizures Clinical Practice Guideline