What are febrile convulsions?

Febrile convulsions are fits or seizures that occur in children due to a fever or temperature above 38°C. About three in every 100 children aged six months to six years will have a convulsion when they have a fever. Fevers are commonly associated with common viral or bacterial infections.

Fever

An increase in body temperature above the normal temperature range. Fever is often caused by the body's immune reaction to infection.

Seizures

A sudden, involuntary contraction of muscle groups caused by abnormal electrical activity in the brain.

Causes

It is thought that some children have brains that are more sensitive than others to abrupt increases in temperature. In these children, a fever caused by common childhood infections is sufficient to trigger seizures. These seizures are not known to damage to the brain or other organs. There is no increased risk of epilepsy in children who have had a febrile convulsion.

Generally, febrile convulsions:

  • Affect around one in 30 children;
  • Tend to run in families, and;
  • Usually occur in children aged from six months to six years.

 

Fever

An increase in body temperature above the normal temperature range. Fever is often caused by the body's immune reaction to infection.

Seizures

A sudden, involuntary contraction of muscle groups caused by abnormal electrical activity in the brain.

Types

There are two main types of febrile seizures:

Simple

Simple febrile convulsions are the most common type. They:

  • Do not last longer than 15 minutes;
  • Do not recur during the period in which your child is unwell, and;
  • Affect widespread areas of the body.

It is common for a child to appear drowsy or confused for a short time after the convulsion ends.

Complex

Complex febrile convulsions are less common. They:

  • Last longer than 15 minutes;
  • Recur within 24 hours, and;
  • Affect specific areas across the body - this is known as a partial or focal seizure.

During a complex febrile convulsion, a child fails to fully recover within one hour.

Seizures

A sudden, involuntary contraction of muscle groups caused by abnormal electrical activity in the brain.

Signs and symptoms

During a febrile convulsion, your child might experience some of the following symptoms:

  • Loss of consciousness or lack of awareness of surroundings;
  • Jerky or twitchy movements of the arms and legs;
  • Foaming at the mouth;
  • Eye-rolling;
  • Loss of control of the bladder or bowel, and;
  • A change in their facial skin colour to red or blue.

Methods for diagnosis

Before diagnosing a febrile convulsion, your doctor may perform tests to ensure the seizures are not caused by a serious underlying illness. Diagnosis typically involves taking a detailed medical history, as well as performing a physical examination, with particular emphasis on the assessment of nerves, and finding the cause of the fever.

If the child is developing normally, their neurological examination is normal, their convulsions fit the criteria for simple seizures, and the cause of the fever is identified, further tests may not be necessary.

Laboratory tests

In some cases, laboratory tests may be performed to exclude other causes of the seizure such as meningitis or dehydration. Such testing may include a lumbar puncture and blood and urine tests.

The blood tests may include a full blood count and blood cultures, which can help the doctor identify if there is an infection, whereas a lumbar puncture may be performed to exclude meningitis. 

If the child's physical examination proves inconclusive, their convulsions fit the criteria for complex seizures and epilepsy is suspected, an electroencephalogram (EEG) may be performed to measure the brainwave activity to confirm a diagnosis of epilepsy.

Dehydration

The state of insufficient hydration; excessive loss of water; requiring more water in order to function normally.

Electroencephalogram

A test to record the electrical activity of the brain, commonly in a person who suffers from seizures, by placing electrodes on multiple areas of the scalp.

Fever

An increase in body temperature above the normal temperature range. Fever is often caused by the body's immune reaction to infection.

Full blood count

A blood test that examines the blood, either by using a microscope or an automated machine, to determine the number of red blood cells, white blood cells and platelets.

Nerves

One or more fibres that transmit signals of sensation and motion between the brain or spinal cord and other parts of the body.

Neurological

Of the nervous system, including the brain.

Seizures

A sudden, involuntary contraction of muscle groups caused by abnormal electrical activity in the brain.

Lumbar puncture

A procedure that uses a needle to collect a sample of cerebrospinal fluid, which is the clear fluid surrounding the brain and spine, from the lower back (lumbar region) for analysis. It can also be performed to remove any excess fluid or to deliver medications.

Types of treatment

During a convulsion:

  • Try to remain calm;
  • Place your child on their side and on a soft surface so that they cannot harm themselves with their movements;
  • Do not restrain your child;
  • Do not slap or shake your child to wake them up;
  • Do not put anything in their mouth, as they may choke on their tongue;
  • Time how long it lasts for, and;
  • Do not place your child in a bath to lower their temperature, as this can be dangerous.

Call an ambulance on 000 if:

  • The convulsion lasts more than five minutes;
  • Your child looks sick when the convulsion ends, such as extreme tiredness, vomiting or symptoms such as a stiff neck, or;
  • Your child does not wake up when the convulsion ends.

If the above do not apply and the convulsion lasts less than 5 minutes, see a doctor as soon as possible.

See a doctor immediately if your child was very sick before the convulsion or if you are worried.

After a convulsion:

Medication

Although fever is the cause of the febrile convulsions, treatment of the fever with paracetamol or ibuprofen has not been shown to be effective in preventing a convulsion.

For treatment of the fever:

  • Ensure your child drinks plenty of fluids;
  • Give them paracetamol if they are in pain or distressed;
  • Do not give them any medication until they are fully awake, and;
  • Keep them cool by not overdressing them and keeping the room at an appropriate temperature.

Fever

An increase in body temperature above the normal temperature range. Fever is often caused by the body's immune reaction to infection.

Potential complications

Although they may be incredibly distressing for parents and caregivers, the majority of febrile convulsions do not cause any long-term harm. Simple febrile convulsions do not lead to brain damage and generally are not caused by a serious underlying condition.

The most common complication of febrile convulsions is having recurring seizures. It is estimated that around a third of children that have one seizure will go on to experience further episodes in subsequent illnesses.

Febrile convulsions are not epilepsy and only 3% of children with febrile convulsions will develop epilepsy. The likelihood of developing epilepsy increases if the child has a family history of epilepsy, or if they have another neurological abnormality or development delay, such as cerebral palsy.

Neurological

Of the nervous system, including the brain.

Seizures

A sudden, involuntary contraction of muscle groups caused by abnormal electrical activity in the brain.

Prognosis

The vast majority of children with febrile convulsions will not need medication or further treatment and have an excellent prognosis.

Prevention

There is no known way of preventing febrile convulsions. The use of paracetamol or ibuprofen at the first sign of a fever has not been shown to prevent the seizures; however, they can help make a child more comfortable while they are unwell.

Fever

An increase in body temperature above the normal temperature range. Fever is often caused by the body's immune reaction to infection.

Seizures

A sudden, involuntary contraction of muscle groups caused by abnormal electrical activity in the brain.