Can seizures occur in the context of congenital asphyxiation?

Seizures in Congenital Asphyxiation

Yes, seizures are a common and expected complication of congenital (perinatal) asphyxiation, occurring in the majority of affected neonates and representing the most prominent neurological manifestation of hypoxic-ischemic encephalopathy.

Epidemiology and Timing

Hypoxic-ischemic injury from perinatal asphyxia is the dominant cause of neonatal seizures, accounting for 46-65% of all neonatal seizure cases 1, 2, 3, 4. This makes asphyxiation the single most common etiology of seizures in the neonatal period.

The temporal pattern is highly characteristic:

• Approximately 90% of infants with hypoxic-ischemic encephalopathy experience seizure onset within the first 2 days after birth 1, 3, 4
• Seizures occurring beyond the seventh day of life are less likely related to asphyxia and more commonly associated with infection, genetic disorders, or malformations of cortical development 1, 4

Pathophysiology and Clinical Significance

The mechanism involves uncontrolled electrical discharges of neurons resulting from lack of oxygen and metabolic abnormalities 1. Seizures can occur as a result of lack of oxygen 1, making them both a consequence of the initial hypoxic-ischemic insult and a potential contributor to ongoing brain injury 5.

Critical Clinical Pitfall

Many neonatal seizures are subclinical or exclusively electroencephalographic without obvious clinical manifestations 2. Continuous video-EEG monitoring is essential to recognize seizures, as not all clinical movements have an EEG correlate and not all EEG seizures have clinical manifestations 2. Relying solely on clinical observation will miss a substantial proportion of seizure activity.

Impact on Outcomes

Seizures in the context of perinatal asphyxia are independently associated with worse neurodevelopmental outcomes, even after controlling for the severity of hypoxic-ischemic brain injury on MRI 6, 7. This relationship demonstrates that:

• Clinical neonatal seizures are independently associated with worse motor and cognitive outcomes 6
• The magnitude of effect varies with seizure severity; children with severe seizures have significantly lower intelligence quotients than those with mild/moderate seizures 6
• Seizure severity is independently associated with increased lactate/choline ratios (indicating impaired cerebral metabolism) and diminished N-acetylaspartate/choline ratios (indicating compromised neuronal integrity) 7
• Electrographic seizures correlate with microcephaly, severe cerebral palsy, and failure to thrive 8

Diagnostic Approach

When evaluating a neonate with suspected asphyxiation and seizures:

Immediate stabilization priorities 2, 3:

• Ensure patent airway, adequate breathing, and circulation
• Continuous monitoring of heart rate, blood pressure, temperature, and oxygen saturation
• Establish IV/IO access immediately

Essential laboratory evaluation 2, 3:

• Point-of-care glucose testing is mandatory to exclude hypoglycemia
• Electrolytes including sodium, calcium, and magnesium
• Blood gas analysis
• Complete blood count and blood culture if infection suspected

Imaging algorithm based on clinical stability 1, 2, 3:

• Head ultrasound as initial bedside imaging if the infant is unstable or MRI unavailable—identifies intraventricular hemorrhage, hydrocephalus, and white matter changes, though it has low sensitivity for hypoxic-ischemic injury
• MRI with diffusion-weighted imaging is the gold standard for identifying hypoxic-ischemic encephalopathy and provides additional diagnostic information beyond ultrasound in 39.8% of patients

Management Considerations

Metabolic correction must precede anticonvulsant therapy 2, 3:

• Correct hypoglycemia with D10%-containing isotonic IV solution at maintenance rate
• Correct hypocalcemia and hypomagnesemia before initiating anticonvulsants

Critical warning: Do not perform lumbar puncture in comatose infants without experienced physician evaluation due to risk of herniation 3.

Prognostic Implications

When perioperative seizures occur in infants with congenital heart disease who also experienced perinatal asphyxia, seizures in the postoperative period are the medical variable most consistently related to adverse neurodevelopmental outcome 1. This underscores the serious prognostic significance of seizures in the context of hypoxic-ischemic injury, whether from isolated asphyxia or combined with cardiac pathology 1.

The absence of major cerebral lesions on MRI is highly predictive of normal neurological outcome, making neuroimaging valuable for prognostication 1.