Risk Factors Of Neonatal Hypoglycemic Brain Injury

Objective To explore the risk factors and imaging or electrophysiological characteristics of neonatal hypoglycemic brain injury by following up with patients diagnosed of neonatal hypoglycemia, so as to find an access to the early diagnosis,effective treatment and prognosis.Methods 71 patients with neonatal hypoglycemia,who were treated in NICU of Children's Hospital during 2002 to 2008,excluded kernicterus, serious inborn infection,complex congenital heart disease, maldevelopment or injury of the brain,and abnormal of chromosome as well, were tested with MRI,EEG,VEP,and intelligence test.The patients were divided into two groups.Group 1 and Group 2 represented for neonatal hypoglycemia with and without perinatal hypoxia ischemia,respectively.A controlled group was also designed to compare the intelligence degree with the hypoglycemic group.The results of the tests were compared with gestational age,birth weight,neonatal CT,MRI,EEG or VEP,the onset time or level of hypoglycemia first detected and the duration or episodes of hypoglycemia as well.Multi logistic regression was used to analyze the risk factors of neonatal hypoglycemic brain injury.Results(1) The incidence of mental retardation between hypoglycemic and controlled groups was of statistical differences.The independent risk factor of bypoglycemic brain injury was the first onset time＞12h(OR10.59) of hypoglycemia.(2)The most common neuroimaging characteristic of hypoglycemia is parietal-occipital lobe injured(about 30%).It is quite difficult for the brain to recover from the occipital abnormality,with OR 15.63.There seems to be a higher risk of patients with neonatal seizure,first onset time＞12h and episodes of hypoglycemia≥5 to become occipital injured,but none of them were independent risk factors.DWI technique can be more sensitive than traditional MR imaging in detecting hypoglycemic brain injuries.The abnormal signal of callous can be reversible.(3) There were no characteristics of neonatal EEG; The lower first onset blood glucose level,the more suppressed impact on the brain.Patients with neonatal EEG abnormalities were more vulnerable to the posterior cerebral damage later,with OR7.33,so that it is quite essential to treat them standardly.It is helpful of EEG in evaluating the level of hypoglycemia and predicting the posterior damage later. (4)The malformation of VEP at follow up seemed to be correlated well with mental retardation(OR 6.33).The independent risk factors of VEP malformation were none AGA(OR5.75),first onset BG≤1.1mmol/L(OR4.70),episodes of hypoglycemia≥5(OR4.70).It is useful of VEP to reflect visual function of the occipital lobes after hypoglycemic brain damage.Conclusions(1)For the babies with later first onset time(＞12h),lower first onset BG level(≤1.1mmol/L),it is of quite importance to maintain normal blood glucose and less episodes(≤4),so as to decrease the incidence of hypoglycemic brain damage.(2) It is necessary for the infants to have VEP,EEG and MRI soon after hypoglycemia in order to predict the severity and prognosis of hypoglycemic brain injury.