Febrile Convulsions

The neurologically abnormal child has never appeared in the exam, with the exception of Question 5 from the first paper of 2014 where febrile convulsions became the subject of detailed interrogation.  By the most recently attempted definition, febrile convulsions are "a seizure occurring in childhood after one month of age, associated with a febrile illness that is not caused by an infection of the central nervous system". There are actually two definitions, which differ slightly. In brief summary, these are seziures which occur in the presence of fever and in the absence of any other good reason for seizures, in an age range variably described as under 6 years, 1 month to five years, 3 months to five years, and six months to six years.

Diagnostic Criteria for Febrile Seizures

International League Against Epilepsy (ILAE) definition

Definition: "a seizure occurring in childhood after one month of age, associated with a febrile illness not caused by an infection of the central nervous system, without previous neonatal seizures or a previous unprovoked seizure, and not meeting criteria for other acute symptomatic seizures"

NIH consensus statement:

Definition: "an event in infancy or childhood usually occurring between three months and five years of age, associated with fever but without evidence of intracranial infection or defined cause for the seizure"

The Royal Children's Hospital Clinical Guidelines has a slightly different age range to both of the above, and closely resembles the college answer. Clearly, both must have the same source.

The list of criteria for the diagnosis of simple febrile convulsions:

  • Fever >38.0°
  • No history of neonatal seizures
  • No previous unprovoked seizures
  • No focal neurological features (i.e. generalised seizure)
  • Tonic-clonic seizure
  • Occurs after 6 months of age, and before the age of 6
  • Lasts less than 15 minutes
  • Occurs only once per episode of febrile illness.

The list of criteria for the diagnosis of complex febrile convulsions:

  • Fever >38.0°
  • No history of neonatal seizures
  • No previous unprovoked seizures
  • Focal seizure
  • Tonic-clonic seizure
  • Occurs after 6 months of age, and before the age of 6
  • Lasts longer than 15 minutes
  • Occurs several times within the same episode of febrile illness.
  • Incomplete recovery after 1 hour.

In Question 5 from the first paper of 2014, the colege asked for five drugs  with which to manage seizures in the paediatric population – one from each class, as well as their dose, their advantages and disadvantages. Such a question lends itself well to a tabulated answer.

Pharmacotherapy of Paediatric Status Epilepticus
Drug Class Dose Advantages Disadvantages
Lorazepam Benzodiazepines 0.05-0.1
mg/kg
Can be given as buccal, IM, PR dose
Rapid onset
 
Respiratory depression
Sedation
Need for airway control
Diazepam Benzodiazepines 0.1-0.3
mg/kg
Midazolam Benzodiazepines 0.1-0.3
mg/kg
Phenytoin Hydantoin 20mg/kg Minimal sedation
No respiratory depression
Prevents seizures over a prolonged period
Not suitable for neonates
Numerous interactions
Levels need to be monitored
Levetiracetam Racetam 5-30mg/kg Very safe
Few interactions
No need for monitoring
Relatively new agent; efficacy unproven
Sodium valproate Organic acid 20-40 mg/kg Effective in refractory cases Hepatotoxic
Levels need to be monitored
Propofol Phenol 1-3 mg/kg Quick onset and offset Respiratory depression
Sedation
Haemodynamic instability
Need for airway control
Phenobarbitone Barbiturate 10-20
mg/kg
More effective than phenytoin
Thiopentone Barbiturate 2-3mg/kg More effective than phenobarbitone
(most effective of all available agents)

Much of this information can be found it its raw untreated form in Slater's chapter on neurological emergencies in children, from Oh's Manual.

References

Oh's Intensive Care manual:  Chapter 109   (pp. 1121) Neurological  emergencies  in  children  by Anthony  J  Slater.

Waruiru, C., and R. Appleton. "Febrile seizures: an update." Archives of Disease in childhood 89.8 (2004): 751-756.

Syndi Seinfeld, D. O., and J. M. Pellock. "Recent Research on Febrile Seizures: A Review." J Neurol Neurophysiol 4 (2013): 165.

Commission on Epidemiology and Prognosis, International League Against Epilepsy. "Guidelines for epidemiologic studies on epilepsy." Epilepsia 34.4 (1993).

Freeman JM. Febrile seizures: a consensus of their significance, evaluation, and treatment. Consensus development conference of febrile seizures. 1980. National Institute of Health.  Pediatrics 1980;66: 1009–12.

Ventura, Alessandro. "From the American Academy of Pediatrics: Clinical Practice Guideline: Febrile Seizures: Guideline for the Neurodiagnostic Evaluation of the Child With a Simple Febrile Seizure." Pediatrics 127.2 (2011): 389-394.

Wright, Chanin, et al. "Clinical pharmacology and pharmacokinetics of levetiracetam." Frontiers in neurology 4 (2013).