Hypoxic-Ischaemic Encephalopathy
📝 Description:
Hypoxic-Ischaemic Encephalopathy (HIE) is brain injury caused by reduced oxygen 🫁 and blood flow ❤️ to the brain 🧠, most often during birth.
It is a leading cause of neonatal seizures, cerebral palsy, intellectual disability, and epilepsy.
Outcome depends on the severity of hypoxia and duration of insult.
🔎 Clinical Features
- 🛌 Altered consciousness - irritability, lethargy, coma.
- ⚡ Seizures within 24–48 hours after birth.
- 💪 Abnormal tone - hypotonia or hypertonia.
- 👶 Abnormal neonatal reflexes - absent Moro, weak sucking.
- 😮💨 Respiratory distress, apnoea, poor feeding.
📊 Sarnat Staging (Severity of HIE)
| Stage |
Features |
Prognosis |
| 🟢 I (Mild) |
Hyperalert, hypertonia, exaggerated reflexes, no seizures |
Usually full recovery ✅ |
| 🟡 II (Moderate) |
Lethargy, hypotonia, weak suck, seizures common, abnormal EEG |
Risk of long-term neurodevelopmental delay ⚠️ |
| 🔴 III (Severe) |
Stupor/coma, flaccid tone, absent reflexes, prolonged seizures, multi-organ dysfunction |
High risk of cerebral palsy, epilepsy, death 🚨 |
🧪 Diagnosis
- 📊 Apgar score: Persistently low at 1 & 5 minutes.
- 🩸 Arterial blood gases: Metabolic acidosis (pH < 7.0, base deficit > 12).
- 🧲 Brain MRI: Gold standard to define injury pattern.
- 📈 EEG/aEEG: Seizure detection + prognostic marker.
- 🧵 Umbilical cord gases: Confirm perinatal hypoxia.
🛠️ Management
- ❄️ Therapeutic hypothermia: Initiate within 6 hours, continue 72 hrs - reduces severity of injury in moderate/severe HIE.
- 💊 Seizure control: Anticonvulsants (phenobarbital 1st-line, levetiracetam increasingly used).
- 🫁 Respiratory & cardiovascular support: O₂, ventilation, fluids, inotropes if needed.
- 👩⚕️ Multidisciplinary input: Neonatology, neurology, physiotherapy, OT, speech therapy.
- 🌱 Neurodevelopmental follow-up: Early intervention programmes, family counselling.
📈 Prognosis
- 🟢 Mild HIE → usually full recovery.
- 🟡 Moderate HIE → variable outcomes: learning difficulties, epilepsy, motor delay.
- 🔴 Severe HIE → high risk of cerebral palsy, profound intellectual disability, refractory epilepsy, or death.
📌 Exam Pearls
- HIE = perinatal asphyxia → neonatal encephalopathy.
- Therapeutic hypothermia must start <6 hrs after birth to be effective.
- EEG/aEEG patterns are strong prognostic markers.
- Always classify with Sarnat staging - examiners love this framework.
