Temporal evolution of hypoxic-ischaemic brain lesions in asphyxiated full-term newborns as assessed by computerized tomography

The association between pro- and anti-inflammatory cytokine polymorphisms and periventricular leukomalacia in newborns with hypoxic-ischemic encephalopathy

Background

Periventricular leukomalacia (PVL) is a frequent consequence of hypoxic-ischemic injury. Functional cytokine gene variants that result in altered production of inflammatory (tumor necrosis factor-alpha [TNF-α] and interleukin-1beta [IL-1β]) or anti-inflammatory (interleukin-10 [IL-10]) cytokines may modify disease processes, including PVL.

Objective

The aim of this study was to evaluate if there is a relationship between the two proinflammatory polymorphisms (TNF-α-1031T/C and IL-1β-511C/T) and the anti-inflammatory polymorphism IL-10-1082G/A and PVL risk in Brazilian newborns with and without this injury.

Materials and methods

A cross-sectional case-control study performed at the Neonatal Intensive Care Unit of the Children’s Hospital and Maternity of the São José do Rio Preto Medical School (FAMERP). Fifty preterm and term newborns were examined as index cases and 50 term newborns as controls, of both sexes for both groups. DNA was extracted from peripheral blood leukocytes, and the sites that encompassed the three polymorphisms were amplified by polymerase chain reaction-restriction fragment length polymorphism.

Results

Gestational age ranged from 25 to 39 weeks, in the case group, and in the control group it ranged from 38 to 42.5 weeks (P<0.0001). Statistically significant association was found between TNF-α-1031T/C high expression genotype TC (odds ratio [OR], 2.495; 95% confidence interval [CI], 1.10–5.63; P=0.043) as well as between genotypes (TC + CC) (OR, 2.471; 95% CI, 1.10–5.55; P=0.044) and risk of PVL. Statistically significant association was found between IL-1β-511C/T high expression genotypes (CT + TT) (OR, 23.120; 95% CI, 1.31–409.4; P=0.003) and risk of PVL. Statistically significant association between IL-10-1082G/A high expression genotype GG (OR, 0.07407; 95% CI, 0.02–0.34; P<0.0001) as well as between IL-10-1082G high expression allele (OR, 0.5098; 95% CI, 0.29–0.91; P=0,030) and PVL reduced risk was observed. There was a statistically significant association between TC/CT/GA genotype combination and the risk of PVL (OR, 6.469; 95% CI, 2.00–20.92; P=0.001).

Conclusion

There is evidence of an association between the polymorphisms TNF-α-1031T/C, IL-1β-511C/T, and IL-10-1082G/A and PVL risk in this Brazilian newborn population studied.

Low Apgar scores and the definition of birth asphyxia

Nonreassuring fetal heart rate patterns, prolonged labor, meconium-stained fluid, a low 1-minute Apgar score, and mild to moderate acidemia have no predictive value for long-term neurologic injury without signs of encephalopathy and seizures. It is important to provide proper resuscitation, support infants, and allow time for evaluation. We have time and the tools to provide fairly predictive information to the families. It is important to use this knowledge wisely in communicating honestly with families, because difficult decisions undoubtedly will arise.

Cardiac arrest: long-term cognitive and imaging analysis

BACKGROUND

Neurological and cognitive sequelae resulting from cardiac arrest (CA), despite their potential personal and social impact, are usually not considered as major outcome measures in long-term analysis of survivors. The aim of this study is to analyze the contribution of neuropsychological testing and cerebral imaging to the development of a long-term classification of neurological impairment.

PATIENTS AND METHODS

A total of 19 patients admitted over a 3 years period in an eight-bed intensive care unit of a tertiary care hospital with a diagnosis of CA were alive and attended a 6-month follow-up consultation. Eleven of these patients agreed to participate in this study carried out between 1 and 3 years after CA. Patients were classified using the Cerebral Performance Categories (CPC), neurological examination, detailed cognitive testing and computerized tomography (CT) scan with qualitative and quantitative imaging analysis.

RESULTS

Six of the 11 patients had good cerebral performance. Verbal and visuo-spatial short-term memory scores were associated with CPC. All patients with at least moderate cerebral disability had abnormal verbal memory test results compared with only one survivor with CPC 1; visuo-spatial short-term memory was abnormal in four moderately affected survivors and normal in those with CPC 1. The bicaudate ratio evaluated in the CT scan was correlated with the verbal memory score while the III ventricle diameter correlated with the executive functions score, suggesting involvement of different brain areas in these functions.

CONCLUSIONS

Neuropsychological and CT scan measurements are proxy measures of long-term impairment of CA survivors, providing a dichotomized global evaluation of CA survivors in close agreement with CPC.

Neuron-specific enolase levels and neuroimaging in asphyxiated term newborns

The study was designed to investigate the cerebrospinal fluid and serum levels of neuron-specific enolase, along with cranial ultrasonography, magnetic resonance imaging (MRI), and electroencephalography (EEG), for predicting the clinical state and neurologic outcome of 26 asphyxiated term newborns. The babies were graded according to the Sarnat and Sarnat classification. Cerebrospinal fluid neuron-specific enolase levels of the 18 babies in the whole hypoxic-ischemic encephalopathy group were higher than the 8 babies in the "no encephalopathy" group. Cerebrospinal fluid neuron-specific enolase levels of 13 cases in the hypoxic-ischemic encephalopathy grade 2 and 3 groups (high-risk group) were higher than both the no encephalopathy and hypoxic-ischemic encephalopathy grade 1 groups when pooled. Cerebrospinal fluid neuron-specific enolase levels of the 7 newborns in the hypoxic-ischemic encephalopathy grade 3 group were also significantly higher than the 5 in the hypoxic-ischemic encephalopathy grade 1 group. The findings of cranial MRI, EEG, and cerebrospinal fluid neuron-specific enolase levels were correlated with each other and the clinical grade of the patients and also were predictive of the neurologic outcome at 1 year of age. Cerebrospinal fluid neuron-specific enolase levels, cranial MRI, and EEG are predictive of outcome of hypoxic-ischemic brain damage in asphyxiated newborns, and this predictivity would increase with the combination of these diagnostic parameters.

The pediatric neurologist as expert witness with particular reference to perinatal asphyxia

The frequency of litigation related to alleged medical malpractice is increasing in Canada. For the neurologist, involvement in such litigation most often takes place in the context of acting as an expert witness and, for the pediatric neurologist, the most common clinical situation for which expertise is requested is that of possible perinatal asphyxia. The medical expert's primary role is to provide necessary guidance and assistance to the court, which may permit the rendering of decisions that are scientifically valid. This article will review the attributes of the medical expert witness. Aspects of perinatal asphyxia cases under litigation that commonly require the assistance of pediatric neurology expertise such as etiology, timing, extent of disability and life expectancy will also be reviewed in detail. The aim is to provide for the neurologist a clearer understanding of the responsibilities inherent in this increasing professional role.

Neonatal neurologic prognostication: the asphyxiated term newborn

The pediatric neurologist is often requested to predict the neurologic outcome in an uncertain situation. A common and problematic clinical setting in which this occurs is the asphyxiated term newborn. This report reviews the predictive tools available for prognostication in this situation and formulates a practical paradigm that the authors hope will improve predictive accuracy and lessen uncertainty in this setting.

Multimodality evoked potentials as a prognostic tool in term asphyxiated newborns

Hypoxic-ischemic (HI) events may cause permanent brain damage, and it is difficult to predict the long-term neurological outcome of survivors. Multimodality evoked potentials (MEPs), using flash visual (fVEPs), somatosensory (SEPs), and brain-stem auditory evoked potentials (BAEPs) may assess the cerebral function in term neonates. MEPs were recorded in 40 hypoxic-ischemic term or near-term neonates during the first week of life in order to predict the neurological outcome. A 3 point grading system registered either mild, moderate, or severe abnormalities. At 24 months of corrected age, the infants were assessed with a blind protocol to determine neurological development. Grade 0 fVEPs and SEPs were associated with a normal neurological status with 100% (P < 0.001) of the infants. Abnormal SEPs or total grade (VEPs + SEPs) > I were not associated with normal outcomes (P < 0.0001). Normal BAEPs did not predict a normal outcome, but severely abnormal BAEPs did predict an abnormal outcome. A significant correlation was found between EP (VEPs + SEPs) grade (r = 0.9, P < 0.0001), Sarnat stage (r = 0.6, P < 0.001), and clinical outcome. This study confirmed that both fVEPs and SEPs are more accurate as prognostic indicators for term neonates. EPs (VEPs + SEPs) also are more accurate in predicting the ultimate neurological outcome compared with the Sarnat scoring.

Imaging of perinatal hypoxic-ischemic brain injury

This article reviews some physiological parameters that influence the location and degree of injury from hypoxia-ischemia. The ability of various imaging tests, particularly magnetic resonance imaging, to detect tissue changes after hypoxia-ischemia is discussed. Most importantly, we evaluate the extent of our knowledge regarding the correlations between imaging, pathophysiological processes, and clinical medicine.

Cranial ultrasound and magnetic resonance imaging in hypoxic-ischaemic encephalopathy: a comparison with outcome

Forty term infants with hypoxic-ischaemic encephalopathy were assessed during the neonatal period with cranial ultrasound and MRI, and the findings were compared with outcome at one year of age. 38 had abnormalities on ultrasound and all had changes on MRI. The incidence of changes in the basal banglia/thalami and periventricular white matter was much greater with MRI than with ultrasound. Changes in the basal ganglia and thalami on MRI were associated with a poor outcome if they had also been detected with ultrasound. However, MRI identified four small infarcts which were not detected by ultrasound. There was no consistent association between periventricular white matter change on MRI and outcome. Regular ultrasound scanning identified all infants with a poor outcome. A normal ultrasound or isolated findings of intraventricular haemorrhage, subarachnoid haemorrhage or transient flares were associated with a normal outcome in 13 of 14 infants.

Serial magnetic resonance imaging in neonatal hypoxic-ischemic encephalopathy

We prospectively performed magnetic resonance imaging (MRI) studies during the neonatal period, and at 4 and 8 months of age, on 15 term infants with hypoxic-ischemic encephalopathy, and compared the results with their neurodevelopmental outcome at 18 months of age. Cerebral palsy developed in nine infants, two infants were classified as having abnormalities of tone and delayed motor milestones that were suggestive of cerebral palsy, and four infants were normal. Structural abnormalities, delayed myelination, or a combination of the two were detected with MRI at 8 months of age in all nine infants with later development of cerebral palsy. Three of the four normal infants and one infant with suggestive abnormalities had normal serial MRI findings. Each of the remaining two infants (one normal, one with suggestive abnormalities) had isolated persistent ventricular dilation on all three MRI studies. Our results suggest that 8 months appears to be the earliest time at which MRI findings correlate well with later adverse neurodevelopmental outcome in this population.

Brain calcification in hypoxic-ischemic lesions: an autopsy review

Calcification of ischemic lesions in a child's brain is well recognized by pathologists; however, clinicians and radiologists usually associate cerebral calcification with infections, particularly the TORCH organisms. We illustrate this phenomenon in a 5-month-old infant with extensive, calcified, multicystic encephalomalacia without evidence of a cerebral infection. In order to ascertain the incidence of cerebral calcification in pure hypoxic-ischemic lesions, we retrospectively analyzed 486 consecutive autopsies. Ninety-nine patients had histologic evidence of cerebral hypoxic-ischemic lesions and hypoxia or ischemia. Thirty-nine of these patients displayed microscopic calcification; 23 patients had slight, 12 had minor, and 4 had prominent calcifications. Prominent calcification lesions were large enough to be detected by routine radiologic methods. Correlations between degree of calcification and the underlying disease process and between the gestational age and the length of survival were not statistically significant. This study illustrates the very frequent occurrence of brain calcification in ischemic brain lesions in children. It is necessary to include this diagnosis in the differential diagnosis of cerebral calcification.

Symmetrical bithalamic hyperdensities in asphyxiated full-term newborns: an early indicator of status marmoratus

Three severely asphyxiated full-term newborns showed tomographic findings of bilateral symmetrical hyperdensities restricted to the thalamic region. All these patients had a strikingly similar poor neurological outcome characterized by dystonia, severe mental retardation and acquired microcephaly. We presume that these bithalamic hyperdensities could be an early predictor of the later status marmoratus.

Cerebral blood flow velocity pattern in healthy and asphyxiated newborns: a controlled study

In a controlled study serial determinations of cerebral blood flow velocity using Doppler ultrasound and repeated real-time ultrasonographic- or computerized axial tomographic studies of the brain were performed in 17 (nearly) full-term newborns who experienced perinatal asphyxia and in 17 healthy matched controls during the first week of life. A higher cerebral blood flow velocity was found during the first 4 days of life, indicating a lower cerebrovascular resistance in the asphyxiated infants compared to the control infants. These haemodynamic changes coincided with cerebral oedema and neurological abnormalities. It is speculated that the changes in the cerebral circulation in asphyxiated infants are at least partly caused by cerebral oedema-induced increase of intracranial pressure due to severe perinatal asphyxia. Serial Doppler ultrasound investigations of the brain may be a useful non-invasive method for early detection and follow-up of the consequences of severe perinatal asphyxia.

Computed tomography of the brain in asphyxiated infants

Perinatal hypoxic-ischemic injury is an important cause of neurological deficit in infants. The hypoxic-ischemic process causes symmetrical periventricular and subcortical hypodense lesions which represent ischemic infarcts. It is important to be able to differentiate these hypodense lesions which represent ischemic infarcts from white matter which is not well myelinated. The temporal pattern of the change in the CT findings may be helpful in differentiating hypodensities due to ischemic infarct from immature myelination.

High density on computed tomography in infantile Krabbe's disease: a case report

In a child with a compatible clinical presentation and course of illness, Krabbe's disease was proven by white blood-cell galactocerebrosidase estimation in the homozygous range. A CT head scan performed at five months of age revealed symmetrical high density in the thalami, posterior limbs of the internal capsules and corona radiata. It also showed low density in the deep white-matter of the cerebral and cerebellar hemispheres and minor cerebral atrophy. Similar CT findings have been recorded in four other cases of infantile Krabbe's disease, and the authors consider that they are sufficient to alert the clinician to the probability of this diagnosis when the clinical signs are appropriate.