cerebral palsy and hypoxic-ischaemic encephalopathy

Overview

HIE results from perinatal asphyxia causing a two-phase brain injury. The latent phase (1-6 hours after resuscitation) is the critical therapeutic window - therapeutic cooling must begin within 6 hours to interrupt secondary energy failure.

Presentation - HIE

•Low APGAR scores - APGAR ≤5 at 10 minutes is a key threshold for cooling eligibility

•Altered tone - hypotonia/flaccidity in moderate-severe HIE

•Altered consciousness - irritability (mild) to coma (severe)

•Seizures - often subtle (lip smacking, cycling limb movements, apnoea)

•Respiratory irregularity - apnoea, bradycardia

Management - HIE (Therapeutic Cooling)

•Eligibility criteria: ≥36 weeks gestation, age <6 hours, pH <7.0 or base deficit ≥16 mmol/L, APGAR ≤5 at 10 minutes, Sarnat stage II-III encephalopathy

•Target temperature: 33.5-34.5°C for 72 hours via whole-body cooling blanket or selective cooling cap

•Mechanism: slows metabolic rate, reduces secondary energy failure cascade (nitric oxide, apoptosis, cerebral metabolism)

•Seizure control: phenobarbital IV

•Blood glucose - treat hypoglycaemia urgently (worsens neuronal injury)

🎯

Therapeutic cooling reduces combined risk of death or major neurodisability by ~25-30% (NNT ~7). Must start within 6 hours - after this window, neuroprotective benefit is lost. IV adrenaline is only appropriate if HR <60 bpm; sodium bicarbonate only if lactic acidosis confirmed on blood gas.

Investigations - HIE

🥇 First-line

•Arterial cord/neonatal blood gas - pH <7.0 or base deficit ≥16 mmol/L supports significant asphyxia

•Amplitude-integrated EEG (aEEG) - detects seizures, assesses background activity, supports cooling eligibility

•Bloods - FBC, CRP, blood culture, LFTs, renal function, coagulation (multiorgan dysfunction common)

🏆 Gold standard

•MRI brain at day 4-7 (after rewarming) - pattern of injury and prognosis

Cerebral Palsy (CP)

Non-progressive brain lesion acquired during brain development causing motor impairment; antenatal causes account for 80-90% of cases, perinatal asphyxia only ~10%.

Presentation - CP

•Delayed motor milestones - not sitting by 9 months, not walking by 18 months

•Hand preference before 12-18 months - suggests hemiplegia

•Abnormal tone - early hypotonia often evolves to hypertonia in spastic CP

•Persistent primitive reflexes - asymmetric tonic neck reflex beyond 6 months

•Comorbidities - epilepsy (30-40%), intellectual disability, visual/hearing impairment, dysphagia, GORD

Management - CP

•Spasticity first-line: physiotherapy/stretching, orthotics (ankle-foot orthoses)

•Spasticity second-line: botulinum toxin A injections (focal) every 3-6 months; baclofen oral or intrathecal pump (generalised/severe)

•Spasticity third-line: selective dorsal rhizotomy (spastic diplegia)

•Epilepsy: anti-seizure medications (30-40% of CP)

•GORD/nutrition: omeprazole or ranitidine; gastrostomy (PEG) for severe dysphagia

•Hip surveillance - essential; spastic quadriplegia carries 50% risk of hip displacement