seizures in childhood kitesh moodley january 2009
TRANSCRIPT
Seizures in Childhood
Kitesh Moodley
January 2009
Introduction• Convulsion associated with febrile disease
– 2-4% of all children before the age of 5 years
• Symptomatic seizures– 0.5-1%
• Epilepsy:– Recurrent unprovoked seizures
• First year of life:– 1,2/1 000
• Childhood and adolescents:– 0,5-1/10000
Aetiology of Epilepsy
• Specific aetiology– Identifiable in only
30% of cases
• Idiopathic 67.6%• Congenital 20%
– Trauma– HIE– Congenital brain
anomalies
• Trauma4.7%
• Infection4.0%
• Vascular1.5%
• Neoplastic 1.5%
Seizure type
Partial (Only a portionof the brain)
- Simple(Normal consciousness)- Complex(Impaired consciousness)
Generalized(Both hemispheres areinvolved)
Epilepsy classification• Clinical presentation is quite variable
– age of onset– seizure type– interictal condition– EEG– Outcome
• Evaluate the: – the epileptic syndrome– Possible aetiology
• The seizure type and syndrome type determine the– Specific appropriate treatment– Further evaluation
ILAE.org
1. Partial seizures– Simple
• With motor symptoms• Autonomic symptoms• Psychic symptoms
– Complex• Simple then altered LOC• Altered LOC from beginning
– Simple or complex which become generalised
• Generalised Seizures– Absence– Myoclonic– Clonic– Tonic– Atonic– Tonic-clonic
Epilepsy syndromes
• Seizures may occur as partial or generalised
• Further divided into – Idiopathic– Symptomatic– Cryptogenic
• Special situations i.e febrile seizures
Main Periods according to Age
• Neonates– Subtle, erratic, non-febrile
• Infancy and early childhood– 3 months to 3 years– Febrile seizures– Infantile spasms– Lennox Gastaut– Myoclonic seizures– Status epilepticus– Partial complex
Main Periods according to Age
• Childhood to early adolescence– Cryptogenic– Absences– Benign rolandic epilepsy
• Nine years to adulthood– Primary generalized epilepsy– Focal epilepsy with brain injury
Stats from ILAE
• Primary tonic-clonic seizures 20%
• Simple partial 20%
• Absence seizures 10% (more in children)
• Other 10%
• 40% of Epilepsy in adults is Complex partial seizures
Neonatal seizures• Subtle seizures
– Deviation of the eyes
– Eyelids are flickering
– Swimming or pedaling movements
– Apnoeic spells
• Tonic
• Clonic
• Myoclonic
• Seldom tonic clonic seizures
Aetiology of neonatal seizures
• Perinatal:– HIE
• Metabolic– Hypoglycemia,
hypocalcemia– hypomagnesemia– Other
• Infections• Structural
abnormalities
Treatment of neonatal seizures
• Optimize ventilation, cardiac output, BP, glucose, electrolytes and pH.
• Treat the underlying disease
• Intravenous line is essential
• Treat the seizures promptly and vigorously
• Phenobarbitone
• Phenytoin
Febrile seizures
• Definition:– Seizure in children between the age of 6
months and 3-4(5) years in association with fever but without evidence of an intracranial infection
• Majority occurs before the age of 3 years
• Average age of onset: 18 months to 22 months
• Boys more than girls
Pathophysiology
• Seizure threshold is low in children
• Susceptible to infections i.e urti, LRTI
• Possible role of endogenous pyrogens IL1– May increase neuronal activity
• Probable role of cytokines
2 Types
• Simple febrile seizures– Generalise– <15min duration– Do not recur within 24hrs
• Complex– Prolonged seizures– Usually more than one in a 24hr period– Or may be focal– Indicative of a more serious condition
Febrile seizures• Recurrence
– 1/3 may have at least one recurrence– The younger the age of onset the greater the risk of
recurrence– Low fever at first seizure– Family hx
• Risk of developing epilepsy– 2% (vs 1% in gen pop)– Risk increases with:
• Complex• Abnormal neurological state
Investigation of febrile seizures
• Lab investigations, although routine, usually unhelpful, in the evaluation of first time seizure – possible just a Na and Glucose
• CT is not warranted in the evaluation of simple febrile convulsions but considered for complex – Study of 71 patient with complex seizures
• None had an intracranial condition requiring treatement
• Routine EEG is seldom necessary
• ??LP– Simple febrile seizure probable not indicated
• Probable those with prolonged post-ictal phase
– Current recommendation should be routine in the under 12 month group
Treatment of febrile convulsion
• Oxygen and supportive care
• Benzodiazapines
• Antipyretics– Do not appear to prvent recurrence
• Councel parents
Treatment of Epilepsy
– Drug treatment should be regular– Simple as possible– Minimum of side effects– Monotherapy– Changes should be made gradually– High initial dosages increases side effects– Rapid withdrawal carries the risk of provoking status– Always calculate the dosage according to the
weight
Treatment of Epilepsy• Drugs commonly used
– Carbamazepine
– Sodium valproate
– Clonazepam
– Phenobarbitone
– Phenytoin
• Newer drugs
– Clobazam
– Oxcarbazepine
– Gabapentin
– Vigabatrin
– Lamotrigine
Treatment of Epilepsy
• Antiepileptics can cause convulsions– Benzodiazepines can induce TC seizures in LGS– Carbamazepine may exacerbate absence
seizures
• What is used as first line treatment.– Absence:
• Sodium valproate
– Focal and Generalized TC:• Carbamazepine
• Status epilepticus (SE) presents in a multitude of forms, dependent on aetiology and patient age (myoclonic, tonic, subtle, tonic-clonic, absence, complex partial etc.)
• Generalized, tonic-clonic SE (GCSE) is the most common form of SE
Definition
• Conventional “textbook” definition of status epilepticus:
– Single seizure > 30 minutes
– Series of seizures > 30 minutes without full recovery
Why 30 minutes ?
Animal experiments in the 1970s and 1980s had shown that ...
… neuronal injury could be demonstrated after 30 min of seizure activity, even while maintaining respiration and circulation
Nevander G. Ann Neurol 1985;18(3):281-90.
More practical: Mechanistic definition
• GCSE is a condition which most likely will not terminate rapidly and / or spontaneously
• GCSE is a condition which requires prompt intervention
Lowenstein DH. Epilepsia 1999
The longer SE persists,
–the lower is the likelihood of spontaneous cessation–the harder it is to control–the higher is the risk of morbidity and mortality
Bleck TP. Epilepsia 1999;40(1):S64-6
The Status Epilepticus Working Party. Arch Dis Child 2000;83(5):415-9.
Typical seizure duration
• Children > 5 years:
Typical, generalized tonic-clonic seizure lasts < 5 minutes
• Young children and infants:
little data. latsts < 10-15 minutes
Reviewed in: Lowenstein DH. It's time to revise the definition of status epilepticus. Epilepsia 1999;40(1):120-2.
Revised Definition
• Generalized, convulsive status epilepticus in older children (> 5 years) refers to > 5 minutes of continuous seizure or >2 discrete seizures with incomplete recovery of consciousness
Causes
• Fever• Medication change• Unknown• Metabolic• Congenital• Anoxic• Other (trauma, vascular,
infection, tumor, drugs)
36%
20%
9%
8%
7%
5%
15%
\\
Mortality
• Adults• Children
15 to 22%
3 to 15%
Reviewed in: Fountain NB. Epilepsia 2000;41 Suppl 2:S23-30Reviewed in: Fountain NB. Epilepsia 2000;41 Suppl 2:S23-30
Mortality
• The primary determinant of mortality and morbidity of SE in children is its aetiology
• With the highest mortality rates caused by an acute neurological condition (infection, trauma, stroke)
Mitchell WG. J Child Neurol 2002;17 Suppl 1:S36-43.Mitchell WG. J Child Neurol 2002;17 Suppl 1:S36-43.
Prolonged seizures
Duration of seizureDuration of seizure
Life Life threateningthreatening
systemicsystemicchangeschanges
DeathDeathTemporaryTemporary
systemicsystemicchangeschanges
Respiratory• Hypoxia and hypercarbia
– Ventilation • (chest rigidity from muscle spasm)
– Hypermetabolism • ( O2 consumption, CO2
production)
– Poor handling of secretions– Neurogenic pulmonary oedema
Hypoxia
• Hypoxia/anoxia markedly increase (triple?) the risk of mortality in SE
• Seizures (without hypoxia) are much less dangerous than seizures and hypoxia
Towne AR. Epilepsia 1994;35(1):27-34
Acidosis
• Respiratory
• Lactic– Impaired tissue oxygenation– Increased energy
expenditure
Haemodynamics
• Sympathetic overdrive – Massive catecholamine /
autonomic discharge– Hypertension– Tachycardia
• Exhaustion– Hypotension– Hypoperfusion
• Exhaustion– Hypotension– Hypoperfusion
0 min0 min 60 min60 min
Cerebral blood flow - Cerebral O2 requirement
Blood pressureBlood pressure
Blood flowBlood flow
OO22 requirement requirement
Seizure duration
Hyperdynamic
Exhaustion
Lothman E. Neurology 1990;40(5 Suppl Lothman E. Neurology 1990;40(5 Suppl 2):13-23.2):13-23.
• Hyperdynamic phase – CBF meets CMRO2
• Exhaustion phase– CBF drops as
hypotension sets in– Autoregulation
exhausted– Neuronal damage
ensues
• Hyperdynamic phase – CBF meets CMRO2
• Exhaustion phase– CBF drops as
hypotension sets in– Autoregulation
exhausted– Neuronal damage
ensues
GlucoseG
luco
se
Seizure duration
30 min
SESE
SE + hypoxiaSE + hypoxia
Lothman E. Neurology 1990;40(5 Suppl 2):13-23.Lothman E. Neurology 1990;40(5 Suppl 2):13-23.
• Hyperdynamic phase – Hyperglycemia
• Exhaustion phase– Hypoglycemia
develops– Hypoglycemia
appears earlier in presence of hypoxia
– Neuronal damage ensues
• Hyperdynamic phase – Hyperglycemia
• Exhaustion phase– Hypoglycemia
develops– Hypoglycemia
appears earlier in presence of hypoxia
– Neuronal damage ensues
Hyperpyrexia
• Hyperpyrexia may develop during protracted SE which impairs substrate delivery while increasing metabolic demand
• Treat hyperpyrexia aggressively– Antipyretics, external cooling
– Ensure normal temperatures
Other alterations
• Increase WCC (50% of children)
• Spinal fluid leukocytosis (15% of children)
• K+
• creatine kinase
• Myoglobinuria
Oxygen, oral airway. Suction. Avoid hypoxia!
Consider bag-valve mask ventilation. Consider intubation
IV/IO access. Treat hypotension, but NOT hypertension
AA
BB
CC
Treatment
Intubate?– It may be difficult to intubate a child with active
seizures
– Stop or slow seizures first, give O2, consider BVM ventilation
– If using paralytic agent to intubate, assume that SE continues
Initial investigations
• Labs– Na, Ca, Mg, PO4 , glucose
– WCC– Liver function tests,
ammonia– Anticonvulsant drug level– Toxicology
Initial investigations
• Lumbar puncture– Always defer LP in unstable patients, but never
delay antibiotic/antiviral treatment if indicated
• CT scan– Indicated for focal seizures or focal deficit or
focal EEG, history of trauma or bleeding disorder
Treatment of convulsive status epilepticus. Recommendations of the Epilepsy Treatment of convulsive status epilepticus. Recommendations of the Epilepsy Foundation of America's Working Group on Status Epilepticus. JAMA 1993;270(7):854-Foundation of America's Working Group on Status Epilepticus. JAMA 1993;270(7):854-9.9.
Treatment
• Give glucose (2-4 ml/kg D25%, infants 5 ml/kg D10%), unless normo- or hyperglycemic
• Hyperglycemia has no negative effect in SE
Treatment
• The longer you wait to administer anticonvulsants, the more anticonvulsants you will need to stop SE
• Most common mistake is ineffective dose
Anticonvulsants
• Rapid acting
plus
• Long acting
Anticonvulsants - Rapid acting
• Benzodiazepines– Lorazepam 0.1 mg/kg i.v. over 1-2
minutes– Diazepam 0.2 mg/kg i.v. over 1-2
minutes
– If SE persists, repeat every 5-10 minutes
Benzodiazepines
• Diazepam– High lipid solubility– Thus very rapid onset – Redistributes rapidly– Thus rapid loss of
anticonvulsant effect– Adverse effects are
persistent:• Hypotension• Respiratory depression
• Lorazepam– Low lipid solubility– Action delayed 2 minutes– Anticonvulsant effect 6-12
hrs– Less respiratory
depression than diazepam
• Midazolam– May be given i.m.
Benzodiazepine - Intramuscular
• Intramuscular midazolam– 0.2 mg/kg i.m. – Aqueous solution is rapidly absorbed,
anticonvulsant effect begins after 2 minutes
• Intramuscular lorazepam– Can be given, but lacks water solubility, thus
later onset than midazolam
Chamberlain JM. Pediatr Emerg Care 1997;13(2):92-4.
Towne AR. J Emerg Med 1999;17(2):323-8.
Anticonvulsants - Long acting
• Phenytoin– 20 mg/kg i.v. over 20 min
– pH 12
Extravasation causes severe tissue injury– Onset 10-30 min– May cause hypotension, dysrhythmia
Anticonvulsants - Long acting
• Phenobarbital– 20 mg/kg i.v. over 10 - 15 min– Onset 15-30 min– May cause hypotension, respiratory
depression– Neurology RXH : no upper limit to phenobarb
• High dose phenobarb for SE will prob need icu admission
If SE persists
• Propofol infusion 5-10 mg/kg/hr after bolus 2 mg/kg
• Midazolam infusion 1 - 10 mcg/kg/min after bolus 0.15 mg/kg
• Isoflurane
Non - convulsive status epilepticus
• How do you tell that patient’s seizures have stopped?
Non - convulsive SE ?
• Neurologic signs after termination of SE are common:– Pupillary changes– Abnormal tone– Abnormal Babinski reflex– Posturing– Clonus– May be asymmetrical
Non - convulsive SE ?
• Up to 20% of children with SE have non - convulsive SE after tonic - clonic SE
• Particularly common in infants < 2 months
Mitchell WG. J Child Neurol 2002;17 Suppl 1:S36-43.Mitchell WG. J Child Neurol 2002;17 Suppl 1:S36-43.
Non - convulsive SE ?
• If child does not begin to respond to painful stimuli within 20 - 30 minutes after tonic - clonic SE stops, suspect non - convulsive SE– Urgent EEG
And Remember
• Airway
• Breathing
• Circulation
• Don’t
• Ever
• Forget
• Glucose