Neonatal seizures and encephalopathy — structured clinical encounter

Station brief (candidate)

You are the neonatal registrar. A term infant born after an emergency caesarean for placental abruption is admitted to the neonatal unit at 2 hours of age with lethargy, hypotonia, depressed primitive reflexes, and rhythmic focal clonic movements of the left arm. Cord blood pH was 6.85, base deficit 16 mmol/L. The team asks you to establish the diagnosis, the neuroprotective plan, and the stepwise antiseizure management. You have 12 minutes with the team and 5 minutes for examiner discussion. [1]

Information available on request

• Term infant (39 weeks), birthweight 3300 g, emergency caesarean for placental abruption; cord pH 6.85, base deficit 16 mmol/L; Apgar scores 1, 3, 5. [1]
• At 2 hours: lethargic, generalised hypotonia, depressed Moro and suck, focal clonic movements of the left arm. Heart rate 140, capillary glucose 3.4 mmol/L. [5]
• aEEG shows a suppressed background with suspected seizure activity; continuous video-EEG has been requested. [8]

Tasks

1. Give the diagnosis and grade the encephalopathy using the Sarnat criteria, justifying it from the history and examination. [1]
2. Outline the neuroprotective intervention for which this infant is eligible, including the target temperature, duration, window for initiation, and the supporting evidence. [1]
3. State your first-line antiseizure medication, its dose and route, and the recommended treatment endpoint. [4] [5]
4. Describe how your management would change if the seizures persisted after the first-line and a second-line agent. [5]

Marking anchors

Must-hit

• Diagnoses moderate hypoxic-ischaemic encephalopathy (Sarnat stage 2) with neonatal seizures, on the basis of cord blood acidosis, the Apgar history, and the lethargy, hypotonia and depressed primitive reflexes. [1]
• Activates therapeutic hypothermia: target 33.5 to 34.5 °C for 72 hours, started within 6 hours of life, citing the TOBY (Azzopardi 2009) and NICHD (Shankaran 2005) trials and the Jacobs 2013 Cochrane meta-analysis for the reduction in death and major disability. [1]
• Checks blood glucose (already normal), gives phenobarbital 20 mg/kg IV as first-line antiseizure medication, and treats to an electrographic endpoint on continuous EEG. [4] [5] [8]

Merit

• Names the ACNS 2011 recommendation: continuous EEG for at least 24 hours after the last electrographic seizure, because most NICU seizures are subclinical. [8]
• For refractory seizures, re-screens for a metabolic and infective cause (ammonia, lactate, lumbar puncture with HSV PCR, MRI) before escalating further, citing the principle that a refractory neonatal seizure is often a missed cause. [5]
• Discusses the antiseizure-medication evidence: Painter 1999 (phenobarbital and phenytoin each ~45–50% cessation), Sharpe 2020 (levetiracetam non-inferior to phenobarbital), and the 2023 ILAE Task Force consensus favouring phenobarbital first line. [4] [5] [7]

Fail

• Withholds or delays cooling to "control the seizures first" — the 6-hour window closes regardless of seizure control. [1]
• Treats to a clinical endpoint alone, ignoring subclinical electrographic seizures. [8]
• Escalates antiseizure drugs in a refractory infant without re-screening for a treatable metabolic or infective cause such as HSV encephalitis or hypoglycaemia. [5]