Neonatal Seizures
Amy Kao, M.D.
Division of Neurology
Doernbecher Children’s Hospital
Objectives
• Review the clinical presentation and
differential diagnosis
• Discuss pathophysiologic implications on
clinical presentation
• Review etiology
• Apply this information to evaluation and
treatment
• Discuss prognosis
Clinical Classification
• Focal/Multifocal Clonic
– Not generalized
– Migratory
– Not necessarily focal etiology
• Focal Tonic
– Not usually generalized
• Generalized Myoclonic
Clinical Classification
• Subtle (“Hypomotor”)
– Motor activity arrest
– Apnea
– Eye deviation
– Autonomic changes
• Motor automatisms
– Oral-buccal-lingual movements
– Swimming
– Bicycling
The Definition of a Seizure
“paroxysmal discharge of cerebral
neurons sufficient to cause clinically
detectable events that are apparent either
to the subject or to an observer”
Definition of a Seizure in a Neonate?
• Excitatory activity predominates
• No paroxysmal discharge on EEG?
– True seizure
• The cortex is undeveloped
• Deeper origin
– “Brainstem release phenomena”
Definition of a Seizure in a Neonate…
• Clinically detectable events?
– Subtle
– Truly only electrographic
• Iatrogenic paralysis
• High doses AEDs
• Encephalopathy or subcortical/spinal
cord damage
If It Isn’t a Seizure, Then What Is It??
• Possible clues
– Stimulus-induced
– Suppressable
– No associated autonomic changes
(usually not bradycardia)
Weird Baby Movements
– Jitteriness
• Stimulus-sensitive
• “Tremor”
• Suppressable
– Benign neonatal sleep myoclonus
– Spinal myoclonus
– Apnea of non-neurologic etiology
• bradycardia
Causes of Neonatal Seizures
• Within first 24 hours of life
– Hypoxic ischemic encephalopathy
– Meningitis/sepsis
– Subdural/Subarachnoid/Interventricular
hemorrhage
– Intrauterine infection
– Trauma
– Pyridoxine dependency
– Drug effect/withdrawal
Causes….
• 24-72 hours
– Meningitis/sepsis
– In premature infants: IVH
– In full-term infants: infarction, venous
thrombosis
– Cerebral dysgenesis
Causes….
• 72 hours to 1 week
– Above causes
– Inborn errors of metabolism
– Hypocalcemia
– Familial neonatal seizures
• 1 week to 4 weeks
– Above causes
– HSV
Other Syndromes
• Benign idiopathic neonatal convulsions
(BINC or Fifth-day fits)
• Benign familial neonatal convulsions
(BFNC)
• Early myoclonic encephalopathy (EME)
• Early infantile epileptic encephalopathy
(EIEE)
• Glucose transporter type I
Evaluation of Neonatal Seizures
•
•
•
•
Serum lytes (gluc, Ca, Mg, Na)
CSF
Head ultrasound
EEG (B6?)
• Tox screen
• CT or MRI of brain
• ?metabolic w/u, congenital infection w/u
Treatment of Electroclinical Seizures
• Phenobarbital 20 mg/kg
– 10 mg/kg boluses until 40-50 microgm/ml
• Phenytoin 20 mg/kg
• Lorazepam 0.1 mg/kg
• Pyridoxine 50-100 mg IV with EEG
Outcome
• 45 % controlled after either phenobarb or
phosphenytoin
• 60 % controlled with both
• 30% of survivors develop epilepsy
• WORSE: HIE, meningitis, dysplasia
• WORSE: electrographic seizures
• BETTER: hypoCa, BINC, BIFC, stroke