The hypoxic ischaemic encephalopathy score in predicting neurodevelopmental outcome in infants with birth asphyxia at the Muhimbili National Hospital.

Abstract

Background: Hypoxic ischaemic encephalopathy (HIE) is known to be associated with significant morbidity and mortality in the full term infant. It is evident from some studies that HIE in the long-term produces a spectrum of neurological disabilities and impairments. This study aimed at assessing the value of the HIE scoring system in predicting early neurodevelopmental outcome of the infants who suffered birth asphyxia. Objective: To assess the value of the HIE score in predicting neurodevelopmental outcome in infants with birth asphyxia at six months of age. Study design: Prospective cohort study. A numeric scoring system for the assessment of HIE during the neonatal period was tested for seven days (or any number of days before discharge or death). The highest score attained at any of these days was used to assess severity of birth asphyxia.

Materials and methods: One hundred and forty infants with a five minute Apgar score of <7 were studied. Eighty-two infants were evaluated at six months of age by taking a history from the mother about development and presence of convulsions. Amiel-Tison method of assessment of motor systems was used to assess the motor function. A modified neurodevelopmental assessment using the Griffith mental developmental charts was used to assess

Vll neurodevelopment at six months. Thirty infants (21 %) of the survivors were lost to follow-up. Outcome measures: Normal development, delayed development, morbidity (convulsions, abnormal muscle tone, cerebral palsy) or death. Results: Twenty- eight (20%) of the infants died during the neonatal period while 112 (80%) survived. The RR of dying during the neonatal period was 20 for moderate HIE and 46 for severe HIE. The PPV for

mortality

was

42.3%

for

moderate

HIE

and

93.8%

for severe HIE. NPV was 98% in both categories. Fifty-eight (70.7%) of the infants were normal at six months of age while 24 (29.3%) had a poor outcome. Of those who had abnormality some had more than one finding. The risk of poor outcome increased with increasing HIE score. Neurodevelopmental abnormalities detected during the SIX months follow-up were convulsions (17%), abnormal muscle tone (21%), delayed developmental age (17%) and cerebral palsy (8.5%). The HIE score had low sensitivity but it was highly specific In detecting the neurodevelopmental abnormalities. The positive and negative predictive values were found to be high. Twenty-three infants (14 boys and 9 girls) had microcephaly by six months of age. HIE score was found to be negatively correlated with the occipital frontal