Causes of neonatal seizures
- Hypoxia-ischemia (i.e. asphyxia)
- Most common cause associated with neonatal seizures.
- Causes of asphyxia
- Prenatal causes
- Without later documentation of acidosis at birth.
- Both antepartum and intrapartum maternal and placental illnesses associated with thrombophilia, preeclampsia, or specific uteroplacental abnormalities such as abruptio placentae or cord compression may contribute to foetal asphyxia stress leading to metabolic acidosis.
- Antepartum maternal trauma and chorioamnionitis are additional conditions that also contribute to the intrauterine asphyxia secondary to uteroplacental insufficiency.
- Intravascular placental thromboses and infarction of the placenta or umbilical cord documented after birth are markers for possible foetal asphyxia.
- Meconium passage into the amniotic fluid also promotes an inflammatory response within the placental membranes, potentially causing vasoconstriction and resultant asphyxia.
- Postnatal causes include
- Persistent pulmonary hypertension of the newborn, cyanotic congenital heart disease, sepsis, meningitis, encephalitis, and primary intracranial haemorrhage are leading diagnoses.
- Hypoxic-ischaemic myoclonic status epilepticus
- See Howard 2011
- Hypoxic-ischaemic brain injury
- Obstruction, suffocation, strangulation
- Cardiac arrest, hypotension, hypovolaemia
- Considered an agonal phenomenon
- Severe damage to cortex, basal ganglia, thalamus
- Arrest or hypoxia
- 1-24h
- Post arrest myoclonic status
- Unrelenting bilateral synchronous focal or generalised jerking
- Uniformly poor prognosis
- 24-48h
- Lance-Adams syndrome (post hypoxic action myoclonus)
- Following respiratory arrest or anaesthetic
- Younger age
- Focal myoclonus action or startle
- Responds to Valproate, Levetiracetam, Piracetam, Clonazepam
- Recovery
- Focal or generalised tonic conic seizures
- Seizure-like activity
- Generalised repetitive trunk and limb movements
- Brain stem ‘shivering’
- Rigors
- Agitation
- Non-epileptic attacks
- Foetal inflammatory response may increase in the risk of unexplained early-onset seizures after intrapartum maternal fever.
- Hypoglycemia
- Hypocalcemia
- Pyridoxine-dependent epilepsy (rare)
Specific syndrome
- Benign familial neonatal epilepsy
- Early myoclonic encephalopathy
- Ohtahara syndrome
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