Paediatric seizures

Febrile seizures

• Definition: Convulsions in a child 6 months to 6 years old in the setting of an acute febrile illness, without previous afebrile seizures, significant prior neurological abnormality, and no CNS infection
• 3% of healthy children
• Benign

Classification

• Simple febrile seizures
  • Generalised, tonic-clonic seizures, lasting <15 minutes that do no recur within the same febrile illness
• Complex febrile seizures
  • Focal
  • Partial
  • >15 minutes duration
  • Recurrent in same febrile illness
  • Incomplete recovery within 1 hour of onset

• Treat as per afebrile seizures
• Reassurance is pertinent
• Paracetamol does not reduce incidence or prevent seizures
• Workup as for febrile infant/child guidelines
  • Primary issue is ensuring the cause for the fever is not dangerous
  • If <6mo re-consider diagnosis
  • Consider LP if <12mo and incomplete immunisations, clinically unwell or on oral antibiotics that may mask meningitis

• Who gets admitted?
  • Complex febrile convulsion
  • Seizures unable to be controlled (by definition, complex)
  • Child clinically unwell
  • Ongoing concern re: nature of febrile illness
• Discharge requirements
  • Normal neurological state after simple febrile convulsion
  • Serious bacterial infection excluded
  • Parental education re: first aid in the event of recurrence and prognosis

• Prognosis
  • The younger the child at first febrile seizure, the greater the risk of repeat febrile seizures
    • 1 year old 50%; 2 years old 30% (overall 25-30%)
  • Risk of epilepsy increased by:
    • FHx of epilepsy
    • Neurodevelopmental issues
    • Atypical febrile convulsions (prolonged or focal)
  • If no risk factors above = 1% rate of epilepsy (similar to population at large)
  • 1 risk factor = 2% rate of epilepsy
  • More than 1 risk factor = 10% rate of epilepsy

• Risk factors for recurrence:
  • Age <12mo
  • Lower temperature before seizure onset
  • Positive FHx of febrile seizures
  • Complex features

Afebrile febrile seizures

• Relatively recently identified phenomenon often seen with gastroenteritis and no recorded fever
• Management and prognosis the same as for febrile seizures

Afebrile seizures (RCH)

• Most convulsions are self-limiting within 5-10 minutes
• Treat immediately if:
  • Presents fitting for unknown period of time
  • Known cause i.e. acquired brain injury, meningitis, trauma, hypoxic injury or underlying cardio-respiratory compromise

• Key considerations
  • Was this actually a seizure
  • Any compromise to ABC, duration, previous episodes
  • Significant past history of seizures, neurological issues, VP shunt, renal failure, endocrinopathies, trauma
  • Focal features
  • Fever
  • Previous anticonvulsant therapy this episode or previously
  • Evidence of underlying cause i.e. hypoglycaemia, meningitis, hypocalcaemia, trauma, stroke, ICH

• First-ever seizure should have formal glucose, electrolytes, calcium, Mg, Phosphate
• Consider long QT syndrome or other arrhythmia
  • Strong emotion or vigorous exercise immediately preceding seizure makes this more likely
  • FHx of sudden cardiac death or arrhythmia
• On history, need to confirm was actually a seizure if possible and if so, any provocative events

• Examination
  • Todd’s paresis = Focal weakness after seizure (can last 48 hours)
  • Skin lesions of tuberous sclerosis
    • Fibrous growths around nails
    • Shagreen patch on back (pebbly, thick skin)
    • Hypomelanotic macules
    • Angiofibromas on face
  • Morphological features of chromosomal disorder
  • Full neurological examination
  • Signs of trauma

• In infants, sudden frequent seizures with failure to regain consciousness is a common presentation of NAI and need to look for retinal haemorrhages

• DDx in infancy
  • Infantile spasms (see later slide)
  • Lennox-Gastaut syndrome
  • Complex partial seizures of infancy
  • Non-epileptic events of infancy
  • Breath-holding spells
  • Benign neonatal sleep myoclonus
  • Benign paroxysmal vertigo
  • Shuddering attacks
  • Self-stimulatory episodes
  • Stereotypes
  • Day dreaming

• DDx in childhood
  • Absence seizures
  • Complex partial seizures
  • Benign focal epilepsy of childhood
  • Nocturnal frontal lobe seizures

• Non-epileptic events of childhood
  • Night terrors
  • Nightmares
  • Paroxysmal kinesigenic dyskinesia
• DDx of late childhood and adolescence
  • Juvenile myoclonic epilepsy
  • Non-epileptiform events
    • Syncope
    • Rage attacks

• Who gets imaging?
  • Focal seizure or examination findings
  • Features suggestive of raised ICP
  • Seizures in the setting of trauma
  • MRI preferred if possible
• Who gets an urgent EEG?
  • Convulsive status treated but patients remains unconscious
  • Altered state of consciousness where complex or partial status is suspected

• Acute management
  • If warrants immediate Rx (see above) or >5-10min duration:
  • IV access, FBC, Chem20, VBG
  • 2mL/kg 10% dextrose if BSL <3
  • Give benzo, repeat after a further 5 minutes if continuing
  • If still continuing after 5 minutes, commence IV phenytoin or phenobarbitone
  • Consider pyridoxine
• Disposition
  • Liaise with paediatric team to arrange review or follow-up after first afebrile seizure
  • If increased frequency or known clusters, warrants admission

Anticonvulsants

• Generalised tonic-clonic: Carbamazepine, phenytoin, valproate
• Absence – Valproate, Ethosuximide
• Myoclonus – Valproate, Clonazepam
• Atonic – Clonazepam
• Topiramate is specific for partial seizures or Lennox-Gastaut syndrome
• Keppra is an adjunct for partial seizures, generalised tonic-clonic and juvenile myoclonic seizures

Starship guidelines

• Treatment should be initiated at 5 minutes in otherwise healthy children (immediately if acquired brain injury)
• Status epilepticus = Recurrent seizures without complete recovery between attacks or continuous seizure activity lasting >30 minutes
• Increasing evidence that earlier treatment is associated with less refractory status epilepticus and possibly better outcome

• Treatment of status epilepticus
  • ABC including oxygen
  • Measure BSL – If <3: 2mL/kg 10% dextrose
  • Check FBC, ABG/VBG, Chem20
  • Consider BC, anticonvulsant levels, toxicology screen, metabolic screen, ammonia + insulin and cortisol levels if hypoglycaemic
  • Consider cefotaxime, acyclovir and CT scan (if focal). Do not do an LP.

• First line
  • Lorazepam 0.1mg/kg IV (max 5mg). Longer duration, possibly more effective and less respiratory depression
  • Diazepam 0.25mg/kg IV (max 10mg)
  • Midazolam 0.15mg/kg IV (max 10mg)
  • If no IV access, IM midazolam 0.2mg/kg, buccal or intranasal midazolam 0.5mg/kg or rectal diazepam 0.5mg/kg

• Second line (if continuing 5 minutes after first TWO doses of first-line agent)
  • Phenytoin 20-30mg/kg IV (max 1g) over 20-30min
  • Phenobarbitone 20-30mg/kg IV over 10-15 min in neonate
• Third line (if continuing 10 minutes after second line agent)
  • Phenobarbitone 20-30mg/kg IV over 10-15min
  • Sodium valproate 40mg/kg iV over 10 min
  • Leviteracetam 40mg/kg IV over 10 min (preferred if possible liver/metabolic disease)
• If still persisting 5 minutes after third-line agent move onto second third-line agent OR pharmacological coma

• Pharmacological coma (will very likely require I&V, CVL, arterial line and continuous EEG monitoring)
  • Midazolam infusion 0.15mg/kg bolus then 2mcg/kg/min
    • If seizures persist, repeat bolus and increase rate by 2mcg/kg/min every 5 min up to maximum 24mcg/kg/min
  • Can give additional phenobarbitone boluses of 10mg/kg
  • Thiopentone infusion if midazolam fails
• Consider pyridoxine 100mg IV to children <18mo if refractory/recurrent seizures. Should respond in 10-60min if pyridoxine-dependent.

Differential

Infantile spasms

• ‘Salaam’ seizures. Sudden flexion of arms, head and trunk.
  • Asymmetrical and extensor spasms can occur
• Occur in clusters for up to 10 minutes duration
• May be mild initially, making diagnosis difficult
• Crucial to diagnose and treat early as ongoing events cause brain injury

Lennox-Gastaut syndrome

• Multiple seizure types
  • Atypical absences
  • Myoclonic seizures
  • Drop attacks
  • Nocturnal tonic seizures
  • Generalised tonic-clonic seizures
• Early phase (often late infancy) may present with atypical absence seizures
  • Slower onset and obscuration rather than complete loss of consciousness
  • Great caution must be exercised with any child <2yo presenting with absences

Complex partial seizures of infancy

• May present as altered consciousness with autonomous symptoms +- apnoea
• Underlying tumour (mostly temporal lobe) may cause this

Breath-holding spells

• Always provoked by unpleasant stimulus
• Usually mild trauma
• May have brief clonic jerking after an episode

Benign neonatal sleep myoclonus

• Myoclonic jerks (can be quite violent and asymmetrical) confined to sleep
• Infant otherwise normal

Benign paroxysmal vertigo

• Sudden acute unsteadiness without ALOC
• Typically clutches to something nearby
• Usually seconds to minutes duration
• May notice nystagmus and occur multiple times per day

Self-stimulatory episodes

• Seen in infant girls with thighes clenched tight, legs crossed at ankles and pelvic undulatory movements
• Infant may look flushed and upset, with sleep afterwards

Stereotypies

• Hand-flapping or repetitive limb movements repeated the same each time
• Common in autism but otherwise normal children also perform these at times

Absence seizures

• Seen in childhood with brief staring spells followed by sudden loss of consciousness and end to the seizure
• No post-ictal period
• Automatisms can also occur
• Events usually <10s seconds and multiple throughout day

Benign focal epilepsy of childhood

• Child wakes at 2-4am, making clucking noise
• Followed by clonic seizure involving one side of body, including face
• Child may be awake during the seizure and find it frightening
• Can become secondarily generalised also

Nocturnal frontal lobe seizures

• Can be mistaken for night terrors or ‘pseudoseizures’
• If multiple stereotyped events per night, very brief or only occur in second half of night, should consider these as possible seizures

Paroxysmal kinesigenic dyskinesia

• Brief dystonic or choreoathetoid movements if provoked by sudden bursts of exercise
• No alteration of consciousness

Last Updated on November 10, 2021 by Andrew Crofton