Status Epilepticus in Children

1
Status Epilepticus in Children

• Toni Petrillo
• Pediatric Critical Care
• Childrens Healthcare of Atlanta

2

• Status epilepticus (SE) presents in a multitude
  of forms, dependent on etiology and patient age
  (myoclonic, tonic, subtle, tonic-clonic, absence,
  complex partial etc.)
• Generalized, tonic-clonic SE is the most common
  form of SE

3
Definition

• Conventional definition
• Single seizure gt 30 minutes
• Series of seizures gt 30 minutes without full
  recovery

4
Definition

• If appropriate therapy is delayed, SE can cause
  permanent neurologic sequelae or death
• thus
• any child who presents actively convulsing
  should be assumed to have SE.
• Haafiz A. Pediatr Emerg Care 199915(2)119-29

5

• The longer SE persists,
• the lower is the likelihood of spontaneous
  cessation
• the harder is it to control
• the higher is the risk of morbidity and mortality
  
• Treatment for most seizures needs to be
  instituted after gt 5 minutes of seizure activity
• Bleck TP. Epilepsia 199940(1)S64-6

6
Causes

• Fever
• Medication change
• Unknown
• Metabolic
• Congenital
• Anoxic
• Other (trauma, vascular, infection, tumor, drugs)

• 36
• 20
• 9
• 8
• 7
• 5
• 15

DeLorenzo RJ. Epilepsia 199233 Suppl 4S15-25
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Drugs which can cause seizures

• Antibiotics
• Penicillins
• Isoniazid
• Metronidazole
• Anesthetics, narcotics
• Halothane, enflurane
• Cocaine, fentanyl
• Ketamine

• Psychopharmaceuticals
• Antihistamines
• Antidepressants
• Antipsychotics
• Phencyclidine
• Tricyclic antidepressants

8
Mortality

• Adults
• Children

• 15 to 22
• 3 to 15

• Reviewed in Fountain NB. Epilepsia 200041 Suppl
  2S23-30

9
Prolonged seizures
Life threatening systemic changes
Temporary systemic changes
Death
Duration of seizure
10
Respiratory

• Hypoxia and hypercarbia
• ß ventilation (chest rigidity from muscle
  spasm)
• Hypermetabolism (Ý O2 consumption, Ý CO2
  production)
• Poor handling of secretions
• Neurogenic pulmonary edema?

11
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 199435(1)27-34

12
Neurogenic pulmonary edema

• Rare complication
• Likely occurs as consequence of marked increase
  of pulmonary vascular pressure

Johnston SC. Postictal pulmonary edema requires
pulmonary vascular pressure increases. Epilepsia
199637(5)428-32
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Acidosis

• Respiratory
• Lactic
• Impaired tissue oxygenation
• Increased energy expenditure

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Hemodynamics

• Sympathetic overdrive
• Massive catecholamine / autonomic discharge
• Hypertension
• Tachycardia
• High CVP

• Exhaustion
• Hypotension
• Hypoperfusion

0 min
60 min
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Cerebral blood flow - Cerebral O2 requirement

• Hyperdynamic phase
• CBF meets CMRO2
• Exhaustion phase
• CBF drops as hypotension sets in
• Autoregulation exhausted
• Neuronal damage ensues

O2 requirement
Blood flow
Blood pressure
Seizure duration
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Glucose

• Hyperdynamic phase
• Hyperglycemia
• Exhaustion phase
• Hypoglycemia develops
• Hypoglycemia appears earlier in presence of
  hypoxia
• Neuronal damage ensues

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Hyperpyrexia

• Hyperpyrexia may develop during protracted SE,
  and aggravate possible mismatch of cerebral
  metabolic requirement and substrate delivery
• Treat hyperpyrexia aggressively
• Antipyretics, external cooling
• Consider intubation, relaxation, ventilation

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Other alterations

• Blood leukocytosis (50 of children)
• Spinal fluid leukocytosis (15 of children)
• Ý K
• Ý creatine kinase
• Myoglobinuria

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A

• Oxygen, oral airway. Avoid hypoxia!
• Consider bag-valve mask ventilation. Consider
  intubation
• IV/IO access. Treat hypotension, but NOT
  hypertension

B
C
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Treatment

• Arterial blood gas?
• All children in SE have acidosis. It often
  resolves rapidly with termination of SE
• Intubate?
• It may be difficult to intubate the actively
  seizing child
• Stop or slow seizures first, give O2, consider
  BVM ventilation
• If using paralytic agent to intubate, assume that
  SE continues

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Initial investigations

• Labs
• Na, Ca, Mg, PO4 , glucose
• CBC
• Liver function tests, ammonia
• Anticonvulsant level
• Toxicology

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Initial investigations

• Lumbar puncture
• Always defer LP in unstable patient, but never
  delay antibiotic/antiviral rx if indicated
• CT scan
• Indicated for focal seizures or deficit, history
  of trauma or bleeding d/o

23
Treatment

• Give glucose (2-4 ml/kg D25, infants 5 ml/kg
  D10), unless normo- or hyperglycemic
• Hyperglycemia has no negative effect in SE
• (as long as significant hyperosmolality is being
  avoided)

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Treatment

• Hyponatremia
• Give 5 cc/kg of 3 (hypertonic saline)
• Hypocalcemia
• Give 20-25 mg/kg of Calcium Chloride

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Treatment

• The longer you wait with anticonvulsant, the more
  anticonvulsant you will need to stop SE
• Most common mistake is ineffective dose

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Anticonvulsants

• Rapid acting
• plus
• Long acting

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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

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Benzodiazepines

• Diazepam
• High lipid solubility
• Thus very rapid onset
• Redistributes rapidly
• Thus rapid loss of anticonvulsant effect
• Adverse effects are persistent
• Hypotension
• Respir 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.

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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
• Cheap

• Fosphenytoin
• 20 mg PE/kg i.v. over 5-7 min PE phenytoin
  equivalent
• pH 8.6
• Extravasation well tolerated
• Onset 5-10 min
• May cause hypotension
• Expensive

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Anticonvulsants - Long acting

• Phenobarbital
• 20 mg/k g i.v. over 10 - 15 min
• Onset 15-30 min
• May cause hypotension, respiratory depression

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Initial choice of long acting anticonvulsants in
SE
Is patient an infant? Is patient already
receiving phenytoin?
Yes
No
At high risk for extravasation ? (small vein,
difficult access etc.)?
Phenobarbital
Yes
No
Phenytoin
Fosphenytoin
32
If SE persists

• Midazolam infusion 1 - 10 mcg/kg/min after bolus
  0.15 mg/kg
• Pentobarbital infusion 1-3 mg/kg/hr after bolus
  10 mg/kg

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Non - convulsive status epilepticus

• How do you tell that patients seizures have
  stopped?

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Non - convulsive SE ?

• Neurologic signs after termination of SE are
  common
• Pupillary changes
• Abnormal tone
• Babinski
• Posturing
• Clonus
• May be asymmetrical

35
Non - convulsive SE ?

• Up to 20 of children with SE have non -
  convulsive SE after tonic - clonic SE

36
Non - convulsive SE ?

• If child does not begin to respond to painful
  stimuli within 20 - 30 minutes after tonic -
  clonic SE, suspect non - convulsive SE
• Urgent EEG

37
References

• Haafiz A, Kissoon N. Status epilepticus current
  concepts. Pediatr Emerg Care 199915(2)119-29.
• Bleck TP. Management approaches to prolonged
  seizures and status epilepticus. Epilepsia
  199940(1)S64-6.
• Orlowski JP, Rothner DA. Diagnosis and treatment
  of status epilepticus. In Fuhrman BP, Zimmerman
  JJ, editors. Pediatric Critical Care. St. Louis
  Mosby 1998. p. 625-35.