Overview of febrile convulsions
In general, fever and convulsions are medically known as “febrile seizures” (FS), formerly also known as “febrile convulsions”, and refer to convulsions that occur when the child’s body temperature suddenly rises due to various causes of fever, but do not include convulsions due to encephalitis, meningitis, or other intracranial infections. It does not include convulsions due to encephalitis, meningitis, or other intracranial infections.
Febrile convulsions are the most common convulsive disorder of childhood, with a prevalence of 2%-4% in children under 5 years of age, with an age of onset of 6 months to 6 years, mostly occurring between 12-18 months of age, with a body temperature usually above 38ºC at onset and a good condition after convulsions. The seizures may seem frightening, but they do not usually cause brain damage or affect intelligence, and having febrile convulsions does not mean that you have epilepsy.
Common causes of febrile convulsions
Infections – Fever accompanied by bacterial or viral infections may cause febrile convulsions, especially human herpes virus type 6 infection (also known as toddler rash or six).
Immune factors – Fever may be a side effect of vaccination, especially after combined measles, mumps and rubella vaccination. This fever usually lasts 8-14 days after vaccination.
Risk factors – A family history of febrile convulsions increases a child’s risk of developing the disease.
Clinical manifestations of febrile convulsions
Febrile convulsions usually appear on the first day of illness, and sometimes they are the first symptom to appear. Most convulsions occur when the body temperature is above 39 ºC. Febrile convulsions are divided into simple febrile convulsions and complex febrile convulsions. They can also be divided into persistent febrile convulsions and recurrent febrile convulsions, depending on the duration and the presence of recurrence.
Simple febrile convulsions – are the most common type. Typical presentation is loss of consciousness, symmetrical, rhythmic twitching of the extremities. Most episodes last less than 1-2 minutes, although sometimes they can last up to 15 minutes; there are no recurrent episodes within 24 hours; the child may be drowsy after the episode, but does not experience weakness of the extremities.
Complex febrile convulsions – relatively rare, with convulsions lasting more than 15 minutes (up to 30 minutes if manifested as cluster seizures); convulsions are limited or markedly asymmetrical; the child may have weakness of the limbs for a short time after the seizure. A diagnosis of complex febrile convulsions can be made if one of the above criteria is present.
Persistent febrile convulsions – refers to a convulsion lasting >30 minutes; or repeated convulsions with no recovery of consciousness between attacks.
Recurrent febrile convulsions – A recurrence of febrile convulsions after a first episode of febrile convulsions, within an interval of several months to several years, is a recurrence of febrile convulsions. The incidence is 30-35%, usually within 1 year of the first episode, and almost always within 2 years of the child’s first episode. High risk factors for recurrence are.
Young children (less than 15 months of age): About 50% of recurrences occur within 6 months of the first febrile convulsion, and only 20% of recurrences occur if the first episode is after 3 years of age.
Frequent fever;
Parents or siblings with a history of febrile convulsions or epilepsy;
Those with a short incubation period between fever and seizure: those with febrile seizures within 1 hour of fever are more likely to have recurrences and have a higher incidence of seizures later in life.
Evaluation and treatment of febrile convulsions
Evaluation – Children with febrile convulsions should be seen immediately to identify the cause of the fever. Caution is needed to rule out meningitis, especially in children younger than 12 months of age. A lumbar puncture is indicated when the following conditions are present A lumbar puncture is performed with a puncture needle that is passed through the lower back and draws a small amount of fluid (known as cerebrospinal fluid or abbreviated as CSF) from the spinal cord cavity. When intracranial infection is suspected, other diagnostic methods such as blood biochemistry, pathogenesis, and cranial imaging are also recommended.
When the presence of signs of meningeal irritation (which may not be evident in small infants) or other clinical features (poor mental reactivity, agitation, bulging fontanelle, abnormal neurological examination) suggest the possibility of meningitis or intracranial infection;
Infants 6-12 months of age who have not been immunized against Haemophilus influenzae type B or Streptococcus pneumoniae should be considered;
Lumbar puncture should be considered when the patient is on antibiotics because antibiotic therapy can mask the signs and symptoms of meningitis.
Treatment – If the convulsion resolves spontaneously, no antispasmodic medication is needed; for prolonged convulsions (more than 5 minutes), antispasmodic medication is usually given, along with monitoring of the child’s heart rate, blood pressure, and respiration; hospitalization is usually not necessary for children with simple febrile convulsions unless a serious infection needs to be treated.
Make sure the child’s surroundings are safe during the attack, place the head on a cushion, remove glasses, and keep the child’s head to the side to avoid choking due to oral secretions; lift the jaw slightly to help keep the airway open; loosen clothing or ties that may restrict movement; do not try to pull the tongue out, as this wrong move can cause a lot of unnecessary damage, including tooth loss, gum damage, tongue injury or even difficulty breathing; do not
Do not press on the limb of the child, as this can lead to fractures, tendon tears, and soft tissue damage; do not press on the person, as there is no scientific evidence that pressing on the person or stimulating the child can end the seizure.
If the seizure lasts longer than 5 minutes, seek immediate medical attention at the nearest hospital or call 120 emergency vehicles for antispasmodic treatment; this includes rectal or intravenous administration of medication.
Also control the body temperature and manage the fever. Physical methods such as acetaminophen, ibuprofen orally or by enema, or warm water baths can be given to reduce fever.
Children with recurrent febrile convulsions can be taught home treatment, including general management of the seizure and how to insert a spare diazepam capsule into the child’s rectum.
Prevention of febrile convulsions
In most cases, the application of prophylactic treatment is not recommended; because the risks and potential side effects of daily application of anticonvulsants outweigh their usefulness. However, it has been suggested that those with frequent febrile convulsions (more than 5 per year) for whom the use of intermittent short-course prophylactic therapy is ineffective, may take long-term oral anti-seizure medication for seizure prevention. Phenobarbital 3-5 mg/(kg-d) or sodium valproate 20-30 mg/(kg-d) is generally chosen for oral administration.
Also, the use of medications (e.g. acetaminophen or ibuprofen) for fever prevention is not recommended when the child is not febrile (e.g. the child just has a cold without fever) because it does not reduce the risk of febrile convulsion recurrence. Antipyretic and symptomatic treatment is advisable for febrile children with a temperature greater than 38ºC.
Follow-up
Long-term follow-up studies have shown that febrile convulsions, whether simple, complex, recurrent, occurring after infection or immunization, do not affect the child’s intellectual or other development. Children with febrile convulsions have only a slightly higher risk of developing epilepsy later in life than children who have never had febrile convulsions.
A number of epilepsies that are closely related to febrile convulsions are being identified that are not caused by febrile convulsions, but rather by a genetic mutation in the child that is easily misdiagnosed as febrile convulsions in early life, including generalized epilepsy with febrile convulsions plus (GEFS+) and severe myoclonic epilepsy of infancy (Dravet syndrome). These epileptic syndromes require screening and follow-up by an experienced pediatric neurologist.