Neurologic Disorders

Perinatal asphyxia

Therapeutic Hypothermia

Seizures

Sub-aponeurotic haemorrhage (SAH)

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Perinatal asphyxia

The biggest concern is hypoxic-ischaemic encephalopathy (HIE) or neonatal encephalopathy. Sometimes the baby is obviously encephalopathic from birth, with prolonged low Apgar’s, delayed onset of breathing, seizures, abnormal posturing etc. Sometimes the features develop more subtly. Any newborn with a one minute Apgar score of ≤5 should be checked neurologically, have a blood gas taken within one hour of birth (for metabolic acidosis), and be observed for at least 6 hours. Time of onset of respiration, as well as the 5 and 10 minute APGARS, should be noted. Apgar’s should be recorded every 10 minutes thereafter until they are >8. 

Any newborn with features of neonatal encephalopathy should be managed as follows:

• NPO initially, with 3 hourly dextrostix
• IV fluids at ⅔ maintenance
• Don’t overheat the baby (may cause ongoing damage to the brain). Nurse in crib not incubator!
• If seizures are observed – give anticonvulsant (phenobarbitone) loading dose
• Consider sepsis/meningitis as a possible cause of asphyxia. Always do a sepsis workup and start ampicillin/penicillin and an aminoglycoside. Lumbar puncture is done in atypical cases or if more than one seizure
• Apply an amplitude EEG

Therapeutic Hypothermia

Cooling of asphyxiated infants to body temperatures between 33-34ºC (therapeutic hypothermia) started within 6 hours of life, has been shown to reduce mortality and disability associated with asphyxia.
Therefore therapeutic hypothermia should be considered post-resuscitation of asphyxiated infants.

Criteria for Therapeutic Hypothermia:

A. All of the following:

• ≥ 36 weeks gestation
• Birth weight ≥ 2000g
• Able to begin cooling by 6 hours of age
• Absence of: congenital abnormalities or signs suggestive of syndromes or chromosomal abnormalities that involve brain dysgenesis; or uncontrolled bleeding, systemic hypotension, persistent pulmonary hypertension FiO₂>0.8

AND

B. Suspected intrapartum hypoxia based on the presence of ANY the following:

• First hour blood gas (cord/arterial/capillary/venous): pH ≤ 7
• or base deficit ≥ 16mmol/l
• 5 and 10 minute Apgar ≤ 5
• Ongoing resuscitation (assisted ventilation, chest compressions, or cardiac medications) for ≥ 10 min

AND

C. Moderate-severe neonatal encephalopathy based on ONE of the following:

• Abnormal amplitude-integrated EEG (aEEG) for at least 30 minutes duration defined by any of the following:
  • Moderate abnormal background (upper margin of the band above 10μV and lower margin below 5 μV)
  • Severe abnormal background (upper margin of the band below 10μV and lower margin below 5 μV)
  • Normal background with seizure activity
• If an aEEG is not available, moderate-severe encephalopathy can be defined clinically by:  
  • Thompson score > 7
    OR
  • Sarnat & Sarnat HIE stage 2 or 3

Protocol for Therapeutic Hypothermia:

• Start hypothermia as soon as possible but not later than at 6 hours of life, preferably in NICU/ High Care, but could be done in ward 16b in no beds are available
• Switch servo-controlled radiant warmer off
• Insert rectal probe by 4-5cm and secure to inner thigh
• Put the patient on the cooling machine
• Aim to keep rectal temperature at 33.5^oC
• Monitor vital signs hourly
• Treat patient according to unit protocol as problems are detected
• Rewarm after 72 hours of hypothermia

Seizures

Neonatal seizures may be subtle e.g. focal clonic movements, apnoeas, abnormal facial movements, horizontal nystagmus. Have a high index of suspicion for seizures.

Investigation:  dextrostix, U&E, Ca²⁺ Mg²⁺ PO^4-, sepsis work-up including lumbar puncture, cranial ultrasound.

Treatment: Treat correctable problems e.g. hypoxia, hypoglycaemia etc.

Start antibiotics usually Ampicillin & Gentamicin 
Phenobarbitone 20 mg/kg IV loading dose- may repeat dose at 10 mg/kg IV. If more than one seizure, start Phenobarbitone maintenance at 5 mg/kg PO nocte.
If still fitting may use Levetiracetam (Keppra) 30-50 mg/kg PO loading dose then 10-30 mg/kg/dose 12hrly as maintenance. 

Sub-aponeurotic haemorrhage (SAH)

Bleeding into the subaponeurotic potential space forms a boggy scalp mass on day one of life. It is commonly associated with vacuum extraction . SAH may initially be difficult to differentiate from caput, but can be distinguished by its larger size often extending into the nape of the neck, anterior to the ears, or onto the upper eyelids. It may also be tender and can cause anaemia and life-threatening haemodynamic instability.

Treatment:

• Vit K 2mg IVI slow bolus 
• Consider fresh frozen/dried plasma 10-20ml/kg IVI over 30 minutes
• Measure head circumference 3 hourly
• If SAH continues enlarging one may repeat treatment, consider blood transfusion, and investigate for bleeding disorder (particularly in males).

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Rahima Moosa Mother and Child Hospital - Neonatal Care Handbook 2023; Neurologic disorders; Perinatal asphyxia, Therapeutic hypothermia, Seizures, Sub-aponeurotic haemorrhage
Last checked for updates: January 2024