Febrile seizure in a child (Febrile Convulsion)
Febrile seizure is a common type of seizure that occurs in young children. It’s diagnosed when a child between 5 months and 6 years of age experiences a convulsion with a fever of at least 38°C (100.4°F). It’s a diagnosis of exclusion, meaning other causes for the seizure must be ruled out.
Typical febrile seizure is generalized tonic-clonic, lasts for a few minutes, and the child does not have an underlying neurological disorder or a history of afebrile seizures.
Atypical Febrile Seizures
Febrile seizure is considered atypical if it has any of the following features:
The seizure is focal (affecting only one part of the body).
It lasts for more than 15 minutes.
The child has two or more episodes within a 24-hour period.
A comprehensive assessment is essential to differentiate a simple febrile seizure from a more serious underlying condition.
History
Gathering a detailed history is the most important step. Key questions include:
Preceding symptoms: What was the child doing before the seizure? Were there any signs of illness?
Seizure details: How did the seizure start? Were there any focal features? Describe the sequence of motor movements.
Past medical history: Has the child had any previous seizures, either febrile or afebrile? Do they have any known neurological or developmental disorders?
Medications: Have they recently taken antibiotics, as this could suggest a partially treated infection like meningitis.
Family history: A family history of febrile seizures, epilepsy, or other neurological diagnoses is relevant.
Examination
A thorough physical examination helps to pinpoint the source of the fever and rule out other serious conditions.
Vitals & Neurological Status: Check the child’s level of consciousness using the AVPU or GCS score.
Head & Skin: Plot the head circumference in young children. Look for any signs of dysmorphism or neurocutaneous markers. Check the skin for any non-blanching rashes, which could indicate meningococcal disease.
Source of Fever: Perform an ENT, chest, and abdominal examination to identify the focus of the infection.
Neurological Exam: Look for signs of meningism (stiff neck, light sensitivity). Check if the anterior fontanelle is open and bulging. A full neurological exam, including cranial nerves and fundoscopy if possible, is crucial to rule out serious intracranial pathology.
Management
Management of a febrile seizure is centered on observation, education, and supportive care.
Diagnosis & Observation: The diagnosis is clinical. The child should be observed for at least 4-6 hours to ensure they return to their baseline.
Investigations: Most children with a typical febrile seizure do not need extensive investigations.
Blood tests (FBC, U&E, Ca, Mg, CRP) are considered if the child is unwell or a systemic illness is suspected.
A lumbar puncture (LP) should be strongly considered if there are signs of meningism or if the child has received recent antibiotics.
Education and First Aid: Educate the parents about febrile seizures using a leaflet. Explain seizure first aid and provide advice on temperature control using antipyretics. However, emphasize that this may not prevent a recurrence.
Medication: Buccal Midazolam may be offered to families if the child has a history of recurrent and prolonged febrile seizures. Routine administration of antipyretics does not prevent febrile seizures.
Red Flags and Risk of Epilepsy
Red Flags
The following signs and symptoms are red flags that suggest the seizure may not be a simple febrile seizure and require further investigation:
Signs of meningism: Especially if the child has a prolonged post-ictal phase or encephalopathy.
Atypical febrile seizure: As defined above.
Underlying neuro-developmental disorder: Conditions like cerebral palsy or autism.
Recent antibiotics: As this may mask signs of a serious infection.
Non-blanching rash: A critical sign of sepsis.
Risk of Epilepsy
While febrile seizures do not cause epilepsy, they can be a harbinger of it in a small percentage of children. The risk of developing epilepsy is increased in children with:
Atypical febrile seizures.
Febrile status epilepticus (a seizure lasting longer than 30 minutes or a series of seizures without recovery in between).
A family history of epilepsy.
An underlying cerebral palsy or other neuro-developmental disorder.
it is possible to estimate the future risk of epilepsy after a febrile seizure in a young child, though it’s important to remember that the overall risk remains low for most children. The estimation is based on the presence of specific risk factors.
While a simple febrile seizure is not considered epilepsy and does not increase a child’s risk of developing it beyond that of the general population, the presence of certain factors can increase the likelihood.
The risk of developing epilepsy is typically categorized as low, intermediate, or high, based on the presence of the following major risk factors:
High-Risk Factors (Three or more factors)
Children with a higher number of risk factors have a significantly increased chance of developing epilepsy, with some studies estimating the risk to be over 10%. These factors include:
Atypical or Complex Febrile Seizures: This is a key predictor. Atypical seizures have one or more of the following features:
Focal seizure activity (affecting only one side of the body).
Prolonged duration (lasting longer than 15 minutes).
Multiple seizures within a 24-hour period.
Pre-existing Neurological or Developmental Abnormality: This includes a diagnosis of cerebral palsy, developmental delay, or other neurological conditions.
Family History of Epilepsy: A history of unprovoked seizures or epilepsy in a parent or sibling.
Intermediate-Risk Factors (One or two factors)
When one or two of the major risk factors are present, the risk of developing epilepsy is moderately increased. The risk is estimated to be between 2.5% and 5%.
Low-Risk Factors (No major factors)
For children with a simple febrile seizure and none of the above risk factors, the chance of developing epilepsy is very low, approximately 1-2%. This risk is similar to that of any other child in the general population.
Additional Considerations
While the factors above are the most significant, other elements may be considered:
Age at First Seizure: Some research suggests that the risk may be slightly higher for children who have their first febrile seizure before 12 months of age.
Genetic Predisposition: A strong family history of febrile seizures can be a risk factor for recurrent febrile seizures and in some cases, can be a sign of a rare genetic epilepsy syndrome like Genetic Epilepsy with Febrile Seizures Plus (GEFS+).
In summary, the prognosis for most children with febrile seizures is excellent. However, a detailed assessment of the seizure characteristics, past medical history, and family history can help estimate a child’s individual risk of developing epilepsy in the future.