Neonatal seizures and encephalopathy — formative SAQs

SAQ 1 — The encephalopathic term infant with seizures (20 marks, ~15 minutes)

A term infant is born after an emergency caesarean for placental abruption. Cord blood pH is 6.85, base deficit 16 mmol/L. Apgar scores are 1, 3, and 5 at 1, 5, and 10 minutes. At 2 hours of age the infant is lethargic with hypotonia and depressed primitive reflexes, and begins having rhythmic focal clonic movements of the left arm. ^[1]

Questions

1. Define the clinical syndrome and grade the encephalopathy using the Sarnat criteria. (4 marks) ^[1]
2. Outline the immediate bedside management, naming the first bedside test and the first-line antiseizure medication with its dose and route. (5 marks) ^[5]
3. Describe the neuroprotective intervention for which this infant is eligible, including the target temperature, duration, and the maximum window for initiation. State the evidence that supports it. (6 marks) ^[1]
4. Explain the role of continuous EEG and the recommended treatment endpoint. (5 marks) ^[8]

Model answer (must-hit)

1. The infant has hypoxic-ischaemic encephalopathy (HIE) with neonatal seizures. The Sarnat stage is moderate (stage 2): lethargy, hypotonia, and depressed primitive reflexes, with seizures. Cord blood acidosis (pH under 7.0, base deficit at least 12 mmol/L) and the Apgar history confirm perinatal asphyxia as the cause. ^[1]
2. Immediate management follows ABC: airway and breathing first, then check the blood glucose (the first bedside test). Give the first-line antiseizure medication — phenobarbital 20 mg/kg intravenously over 10 to 20 minutes. If the glucose is low, give 10% dextrose 2 mL/kg intravenously. Start continuous video-EEG to confirm and guide treatment. ^{[4] [5]}
3. The infant is eligible for therapeutic hypothermia: target 33.5 to 34.5 °C for 72 hours, started within 6 hours of life. This is supported by the TOBY trial (Azzopardi 2009), the NICHD whole-body hypothermia trial (Shankaran 2005), and the Jacobs 2013 Cochrane meta-analysis, which collectively showed that cooling reduces death and major disability in term infants with moderate-to-severe HIE. Rewarm slowly at 0.5 °C per hour. ^[1]
4. Continuous video-EEG is the gold standard because most NICU seizures are subclinical (electrographic-only); clinical observation alone misses them. The ACNS 2011 guideline recommends continuous EEG for any infant with a suspected seizure or at high risk (cooling HIE), continued for at least 24 hours after the last electrographic seizure. The treatment endpoint is electrographic cessation, not clinical cessation. ^[8]