15.5.5.1 Febrile Seizures

Question 1

Fabrile seizures general

Answer 1

• Provoked by fever
• Prevalence: 2-5% of children.
• Age of onset : 6 months to 5 years.
• Most occur in the presence of an identifiable infection.
• It remains unclear whether the triggering factor is the degree of fever or the rapidity of it’s rise.
• It is essential that CNS infections (meningitis) are excluded
• A viral infection is implicated in more than 80% of cases.

Question 2

Classification of fabrile seizures

Answer 2

Simple
- generalized tonic-clonic (shakes on both sides/ just go stiff)
- <15 minutes in duration
- no recurrence within 24hrs or within same febrile illness

Complex
- focal features
- >15 min in duration
- 2 or more within 24 hrs or within same febrile illness

Question 3

Risk of further febrile seizure

Answer 3

• Overall risk ~30%
• risk of recurrence = 3rd
• Risk Factors:
  • Early age of onset (<18months)
  • Family history of febrile seizures
  • Lower temperature (<40°C)

Question 4

Risk of developing epilepsy

Answer 4

• Overall ~3% develop epilepsy
• Risk factors:
  • Abnormal‘neurology’ prior to first febrile seizure
  • Family history of epilepsy
  • Complex febrile seizure

Question 5

Febrile seizures and learning problems

Answer 5

Numerous large studies have investigated the relationship between recurrent febrile seizures and learning and found no significant difference in intellectual outcome.

Question 6

Risk of death

Answer 6

• A theoretical risk of febrile seizures is death or brain injury by aspiration. So far no deaths associated with simple febrile seizures have been reported.
• There is no evidence that SUDEP (Sudden Unexpected Death in Epilepsy) occurs in association with febrile seizures.

Question 7

Investigations of febrile seizure

Answer 7

• Direct evaluation should be aimed toward the cause of the child’s fever. Exclude underlying infection of the CNS.
• A Lumbar puncture should be strongly considered in any child under the age of 18 months since the clinical signs and symptoms associated with meningitis may be absent or subtle.
• Blood biochemistry, CT scan and EEG’s are not routinely indicated.

Question 8

Criteria for hospital admission

Answer 8

• Age <1 yr
• Glasgow Coma Scale <15 one hour after seizure
• ‘Meningism’ or signs of raised intracranial pressure
• Unwell
• Signs of respiratory aspiration
• High parental or carer anxiety
• Complex febrile seizure

Question 9

Advice to the parents prior to discharge

Answer 9

• Familial reassurance and support should form the mainstay of treatment.
• Antipyretic advice (although may not influence likelihood of seizure) The stripping of clothes, opening of window and use of a fan should be avoided as it may cause peripheral vasoconstriction (increase the core temperature).
• Seizure first-aid advice.
• Consider ‘rescue medication’ (diazepam) if prolonged

Question 10

Summary

Answer 10

• Febrile seizures are one of the commonest type of seizures encountered in pre-school children
• They are usually‘benign’
• They do not require AED prophylaxis
• Most children with febrile seizures do not develop recurrent afebrile seizures (epilepsy) although the risk of epilepsy is increased