Acute neurological findings in a national cohort of neonates with severe neonatal hyperbilirubinemia

Neonatal hyperbilirubinemia and repercussions on neurodevelopment: A systematic review

BACKGROUND

Accumulation of bilirubin above normal levels is considered a neurological risk factor for both premature and full-term newborns. This systematic review aimed to determine the effect of neonatal hyperbilirubinemia on neurodevelopment in preterm and full-term newborns.

METHODS

PubMed, EMBASE, Cochrane Library, CINAHL, PsycINFO, Scopus and Lilacs databases were searched for articles published until 1 June 2022. The quality of cohort and case-control studies was assessed with the Newcastle-Ottawa Scale, and the MINCir scale was used to evaluate the methodological quality of therapy studies or the therapeutic procedures. Premature neonates without neurological conditions and those born at term with hyperbilirubinemia as the sole risk factor were included. Studies reporting one or more neurodevelopmental outcomes were included with an inter-group comparison of a hyperbilirubinemia group versus a non-hyperbilirubinemia or non-pathological hyperbilirubinemia group. The main outcomes were auditory function, visual function, cognitive function, motor function, behavior, global development and neurological risk.

RESULTS

The search identified 951 studies, 19 of which (n = 2210 newborns) were finally included. Fifteen of the cohort and case-control studies presented low risk of bias, and six studies showed high methodological quality. Within the preterm population, hyperbilirubinemia as the sole risk factor was not shown to affect neurodevelopment. Auditory, neurological and motor development alterations were found in the population of full-term newborns with hyperbilirubinemia, which were more evident during the first year of life.

CONCLUSIONS

Elevated bilirubin levels may be a trigger for the onset of neurodevelopmental disorders in full-term infants during the first year of life. More studies are warranted in the preterm population with hyperbilirubinemia to draw conclusions about its impact on their neurodevelopment.

BIND score: A system to triage infants readmitted for extreme hyperbilirubinemia

Extreme hyperbilirubinemia [EHB, total serum bilirubin (TB) >25 mg/dL]) can lead to death, acute bilirubin encephalopathy (ABE), exchange transfusion, and/or bilirubin-induced neurologic dysfunction (BIND). In specific low- to middle-income countries, an "epidemic" exists, therefore, a simplified triage management system is needed. Here, we studied a cohort of 72 infants readmitted for EHB (TB: 28.1 ± 2.5; range: 25-42 mg/dL). Of these, 15/72 (20.8%) newborns had BIND scores ≥4. Eleven (15.3%) infants with BIND scores of 4 to 6 developed moderate ABE, with 6/11 (54.5%) with TB of 28.1 ± 4.8 mg/dL having post-icteric sequelae. Eight infants (TB of 32.1 ± 3.5 mg/dL) had BIND scores >6 and developed adverse outcomes. One infant, who had Rh disease and a BIND score of 8 died. We report that the key determinants for adverse outcomes were TB >30 mg/dL and a BIND score ≥4 and may be useful for a systems approach to triage infants readmitted for EHB.

Can bilirubin/albumin ratio predict neurodevelopmental outcome in severe neonatal hyperbilirubinemia? A 3-month follow up study

Background

The risk of kernicterus and BIND may be in part determined by total serum bilirubin (TSB) and by the level of non-albumin bound free bilirubin, which can easily pass the blood–brain barrier. Free bilirubin (Bf) seems a more reliable predictor for bilirubin neurotoxicity. Bilirubin/albumin ratio (B/A) is considered a surrogate parameter for Bf and has been more useful than TSB. The aim of the study is to determine whether B/A ratio correlates with BIND in newborns with severe hyperbilirubinemia and if it can predict poor neurologic outcome at 3 months follow up.

Results

This prospective study included one hundred seventeen outborn neonates ≥ 35 weeks admitted in a tertiary care neonatal intensive care unit, between May and December 2012, with TSB ≥ 20 mg/dl or necessitating exchange transfusion. Total serum bilirubin and serum albumin were done on admission and bilirubin/albumin ratio was calculated. BIND score was calculated. At the age of 3 months, 112 neonates were followed up with a detailed neurological assessment. Babies who depicted any abnormal motor examination were subjected to brain stem auditory evoked response and MRI examination. Seven infants (6.2%) presented with kernicterus on follow up. BIND scores on admission, mean TSB, and bilirubin/albumin ratio was significantly higher in kernicteric infants compared with those having normal neurological outcome at 3 months of age (P 0.001). The lowest TSB level at which kernicterus occurred in our study was 31 mg/dl. Receiver operation characteristics analysis identified B/A ratio cut off value for predicting kernicterus of 9.6 with sensitivity of 100% and specificity of 91.4%, whereas TSB cut off value of 30 mg/dl showed sensitivity of 100% and specificity of 83%.

Conclusion

B/A ratio is a strong indicator for the risk of kernicterus. B/A is more specific than TSB and should be used in the early management of neonatal hyperbilirubinemia.

Diagnostic value of combination of cranial MRI, serum homocysteine and procalcitonin for hyperbilirubinemia complicated with brain injury in neonates

The present study aimed to explore the diagnostic value of the combination of cranial magnetic resonance imaging (MRI), serum homocysteine (HCY) and procalcitonin (PCT) for hyperbilirubinemia complicated with brain injury in neonates. One hundred and forty-nine children with hyperbilirubinemia admitted to Shandong Medical Imaging Research Institute from January 2014 to April 2016 were collected as research subjects, and were divided into a brain injury group (n=67) and a non-brain injury group (n=82) according to whether children suffered from brain injury. PCT levels were detected by electrochemiluminescence (ECL), and HCY levels by enzymatic cycling assay (ECA). The combination of cranial MRI, HCY and PCT was used to diagnose hyperbilirubinemia complicated with brain injury in neonates. The concentrations of HCY and PCT in the brain injury group were significantly higher than those in the non-brain injury group (P<0.001). According to the MRI examination results, the patients were divided into an MRI normal group and an MRI abnormal group. In the brain injury group, the serum HCY and PCT levels of the MRI abnormal group were significantly higher than those of the MRI normal group, with a statistically significant difference (P<0.05). In the non-brain injury group, the serum HCY and PCT levels of the MRI abnormal group were significantly higher than those of the MRI normal group, with a statistically significant difference (P<0.05). The sensitivity of the combined detection was significantly higher than that of single detection (P<0.05); the specificity was significantly higher than that of HCY detection (P<0.05), and the accuracy was significantly higher than that of MRI and HCY single detection (P<0.05). In conclusion, the combination of cranial MRI, HCY and PCT, which has a high diagnostic value for hyperbilirubinemia complicated with brain injury in neonates, is conducive to the early diagnosis and timely treatment of the disease and the reduction of sequelae.

Extreme neonatal hyperbilirubinemia and kernicterus spectrum disorder in Denmark during the years 2000-2015

OBJECTIVE

To determine the incidence and etiology of extreme neonatal hyperbilirubinemia, defined as total serum bilirubin (TSB) ≥450 µmol/L, and kernicterus spectrum disorder (KSD) in Denmark between 2000 and 2015.

STUDY DESIGN

We identified all infants born between 01.01.2000 and 31.12.2015 with TSB ≥450 µmol/L, ratio of conjugated to TSB <0.30, gestational age ≥35 weeks, and postnatal age ≤4 weeks, using Danish hospitals' laboratory databases.

RESULT

We included 408 infants. The incidence of extreme neonatal hyperbilirubinemia among infants with gestational age ≥35 weeks was 42/100,000 during the study period with a seemingly decreasing incidence between 2005 and 2015. Twelve of the 408 infants developed KSD, (incidence 1.2/100,000) Blood type ABO isohemolytic disease was the most common explanatory etiology.

CONCLUSIONS

Our study stresses the importance of a systematic approach to neonatal jaundice and ongoing surveillance of extreme neonatal hyperbilirubinemia and KSD.

Report about term infants with severe hyperbilirubinemia undergoing exchange transfusion in Southwestern China during an 11-year period, from 2001 to 2011

OBJECTIVES

This study was intended to explore the etiology and risk factors of severe neonatal hyperbilirubinemia and to analyze the adverse events associated with ECT (Exchange Transfusion), as well as to identify the factors related to the poor prognosis.

METHODS

All of the full-term neonates who had undergone ECT for hyperbilirubinemia at Children's Hospital of Chongqing Medical University from January 2001 to December 2011 were enrolled in this study. General demographic characteristics, comorbidities, pre- and post-exchange TSB(Total Serum Bilirubin) levels, duration and frequency of ECT, and clinical outcomes were recorded and analyzed anonymously.

RESULTS

Of 614 total infants, 368 patients (59.9%) with ABO incompatibility were identified, of whom 197 (53.5%) developed acute bilirubin encephalopathy (ABE) and 16 (4.3%) suffered a poor prognosis. The etiology was unidentified in 103 patients (16.8%), of whom 62 (60.1%) developed ABE and 9 (8.7%) had a poor prognosis. Identified adverse events secondary to ECT included thrombocytopenia (54.6%), hyperglycemia (42.8%), apnea (3.3%) and necrotizing enterocolitis (NEC) (1.3%). No ECT-related mortality was documented in this study.

CONCLUSIONS

The etiology, peak TSB level before ECT, and time of ECT had a significant impact on the outcome of severe neonatal hyperbilirubinemia. ABO incompatibility was the most common cause of extreme neonatal hyperbilirubinemia. Pathological weight loss could be involved in the development of extreme hyperbilirubinemia with an unidentified cause.

Revisiting the Criteria for Exchange Transfusion for Severe Neonatal Hyperbilirubinemia in Resource-Limited Settings

BACKGROUND

Exchange transfusion (ET) for severe neonatal hyperbilirubinemia (SNH) is frequently undertaken in low- and middle-income countries (LMIC), in sharp contrast to the prevailing practice in high-income countries. However, the criteria for initiating this procedure in settings with limited resources for treating infants with SNH have not been systematically explored.

OBJECTIVE

To identify key considerations for initiating ET in resource-poor countries to curtail its unnecessary use for the prevention of kernicterus.

METHODS

A review of the existing guidelines and literature on the management of neonatal hyperbilirubinemia worldwide was conducted to identify criteria and underlying factors for initiating ET.

RESULTS

There is a dearth of evidence from randomized clinical trials to support clear criteria for indicated ET worldwide. Because risk assessment for kernicterus based solely on the levels of total serum bilirubin (TSB) has often proved inadequate, a combination of plasma/serum bilirubin estimation and clinical evaluation for acute bilirubin encephalopathy (ABE) has been recommended for predicting the risk of kernicterus. However, there is a lack of consistency regarding the TSB levels for which ET should be initiated in relation to the clinical signs/symptoms of ABE and hemolytic disorders.

CONCLUSIONS

A decision-making framework that combines TSB thresholds and evidence of neurotoxicity is needed for evaluating the risk of kernicterus and prioritising infants for ET in LMICs to curtail unnecessary interventions.

Transcutaneous bilirubinometry

Although the modern era of transcutaneous bilirubin monitoring (TcB) began only about 35 years ago, this screening tool is now widely used in newborn nurseries and outpatient clinics, offices, and emergency departments to obtain a rapid and non-invasive estimate of the degree of hyperbilirubinemia. TcB devices have become more sophisticated, and major breakthroughs include the following: (a) ability to report a bilirubin value rather than an index value, (b) enhanced correction for chromophores other than bilirubin, and (c) technologic improvements including interface with electronic medical records. Good agreement with laboratory bilirubin measurement has been demonstrated, and the ability of TcB screening to predict and decrease the incidence of subsequent hyperbilirubinemia has been well-documented. To date, it has not been shown that this screening results in improved long-term outcomes.

Neonatal hyperbilirubinemia and Rhesus disease of the newborn: incidence and impairment estimates for 2010 at regional and global levels

BACKGROUND

Rhesus (Rh) disease and extreme hyperbilirubinemia (EHB) result in neonatal mortality and long-term neurodevelopmental impairment, yet there are no estimates of their burden.

METHODS

Systematic reviews and meta-analyses were undertaken of national prevalence, mortality, and kernicterus due to Rh disease and EHB. We applied a compartmental model to estimate neonatal survivors and impairment cases for 2010.

RESULTS

Twenty-four million (18% of 134 million live births ≥ 32 wk gestational age from 184 countries; uncertainty range: 23-26 million) were at risk for neonatal hyperbilirubinemia-related adverse outcomes. Of these, 480,700 (0.36%) had either Rh disease (373,300; uncertainty range: 271,800-477,500) or developed EHB from other causes (107,400; uncertainty range: 57,000-131,000), with a 24% risk for death (114,100; uncertainty range: 59,700-172,000), 13% for kernicterus (75,400), and 11% for stillbirths. Three-quarters of mortality occurred in sub-Saharan Africa and South Asia. Kernicterus with Rh disease ranged from 38, 28, 28, and 25/100,000 live births for Eastern Europe/Central Asian, sub-Saharan African, South Asian, and Latin American regions, respectively. More than 83% of survivors with kernicterus had one or more impairments.

CONCLUSION

Failure to prevent Rh sensitization and manage neonatal hyperbilirubinemia results in 114,100 avoidable neonatal deaths and many children grow up with disabilities. Proven solutions remain underused, especially in low-income countries.

Incidence of and risk factors for neonatal jaundice among newborns in southern Nepal

OBJECTIVE

To quantify the incidence of and risk factors for neonatal jaundice among infants referred for care from a rural, low-resource, population-based cohort in southern Nepal.

METHODS

Study participants were 18,985 newborn infants born in Sarlahi District in southern Nepal from May 2003 through January 2006 who participated in a cluster-randomised, placebo-controlled, community-based trial to evaluate the effect of newborn chlorhexidine cleansing on neonatal mortality and morbidity. Jaundice was assessed based on visual assessment of the infant by a study worker and referral for care. Adjusted relative risks (RR) were estimated to identify risk factors for referral for neonatal jaundice using Poisson regression.

RESULTS

The incidence of referral for neonatal jaundice was 29.3 per 1000 live births (95% confidence interval: 26.9, 31.7). Male sex, high birth weight, breastfeeding patterns, warm air temperature, primiparity, skilled birth attendance, place of delivery, prolonged labour, oil massage, paternal education and ethnicity were significant risk factors (P-values < 0.01). After multivariable adjustment, sex, birth weight, difficulty feeding, prolonged labour, primiparity, oil massage, ambient air temperature and ethnicity remained important factors. Among infants with difficulty feeding, exclusive breastfeeding was a risk factor for neonatal jaundice, whereas exclusive breastfeeding was protective among infants with no report of difficulty feeding.

CONCLUSIONS

Several known risk factors for neonatal jaundice in a low-resource setting were confirmed in this study. Unique observed associations of jaundice with ambient air temperature and oil massage may be explained by the opportunity for phototherapy based on the cultural practices of this study population. Future research should investigate the role of an infant's difficulty in feeding as a potential modifier in the association between exclusive breastfeeding and jaundice.

Should we screen newborns for glucose-6-phosphate dehydrogenase deficiency in the United States?

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, a common X-linked enzymopathy can lead to severe hyperbilirubinemia, acute bilirubin encephalopathy and kernicterus in the United States. Neonatal testing for G6PD deficiency is not yet routine and the American Academy of Pediatrics recommends testing only in jaundiced newborns who are receiving phototherapy whose family history, ethnicity, or geographic origin suggest risk for the condition, or for infants whose response to phototherapy is poor. Screening tests for G6PD deficiency are available, are suitable for use in newborns and have been used in birth hospitals. However, US birth hospitals experience is limited and no national consensus has emerged regarding the need for newborn G6PD testing, its effectiveness or the best approach. Our review of current state of G6PD deficiency screening highlights research gaps and informs specific operational challenges to implement universal newborn G6PD testing concurrent to bilirubin screening in the United States.

Neurodevelopment after moderate hyperbilirubinemia at term

BACKGROUND

The aim of this work was to investigate in a prospective study whether moderate hyperbilirubinemia in healthy term neonates is associated with an increase of minor neurological dysfunction (MND) and behavioral problems up to 18 mo.

METHOD

We enrolled 43 healthy term infants with a bilirubin level ≥ 220 µmol/l (BILI group) at 72-96 h postnatally at the University Medical Center Groningen (UMCG), including eight referrals for hyperbilirubinemia. Seventy healthy term infants born at the UMCG with bilirubin level <220 µmol/l served as comparisons (COMP group). We evaluated the neurologic condition neonatally and at 3 and 18 mo; behavior was evaluated at birth and 18 mo.

RESULTS

Rates of MND in BILI and COMP groups were similar at all ages. However, bilirubin levels of ≥ 300 µmol/l (n = 10) were associated with an increased risk of complex MND (odds ratio: 4.21; 95% confidence interval: 1.02-17.37). Neonatally, BILI infants were more often lethargic than COMP infants (odds ratio: 3.54; 95% confidence interval: 1.32-9.51); at 18 mo, they had higher hyperactivity scores (effect: 0.32; 95% confidence interval: 0.08-0.56).

CONCLUSION

Occurrence of complex MND at 18 mo in infants with moderate hyperbilirubinemia was not different from that in comparison infants, but bilirubin level ≥ 300 was associated with an increased risk of complex MND. This study also suggests that minor behavioral effects of moderate hyperbilirubinemia cannot be excluded.

Perinatal and early postnatal factors underlying developmental delay and disabilities

A delay in meeting developmental milestones may be secondary to perinatal events, involving complicated interactions between mother and fetus during delivery. Maternal factors including weight, diet, and morbidities can affect neonatal adaptation and later development. Prematurity, low birth weight, and previous intrauterine insults as well as complications during delivery of a previously normal fetus increase the risk for perinatal stress. In this article, the literature on perinatal and early postnatal factors that underlie risks for developmental delay and disabilities is reviewed. Studies that concern neuroprotective therapies and prediction of long-term neurologic outcome by clinical examination, neuroimaging techniques, and electroencephalographic studies are reviewed as well.

Risk factors for neurotoxicity in newborns with severe neonatal hyperbilirubinemia

OBJECTIVE

To evaluate the importance of total serum bilirubin (TSB) and neurotoxicity risk factors in predicting acute bilirubin encephalopathy (ABE) at admission or posttreatment bilirubin encephalopathy (BE) in infants with severe hyperbilirubinemia.

METHODS

We analyzed the interaction of TSB and risk factors as determinants of ABE and BE in 249 newborns admitted with a TSB level of ≥ 25 mg/dL (427 μmol/L) to Cairo University Children's Hospital during a 12-month period.

RESULTS

Admission TSB values ranged from 25 to 76.4 mg/dL. Forty-four newborns had moderate or severe ABE at admission; 35 of 249 infants (14%) had evidence of BE at the time of discharge or death. Rh incompatibility (odds ratio [OR]: 48.6) and sepsis (OR: 20.6) greatly increased the risk for ABE/BE, but TSB levels correlated poorly with the presence or absence of ABE or BE in these patients. The OR for ABO incompatibility with anemia (1.8) was not statistically significant. Low admission weight (OR: 0.83 per 100 g) increased the risk for BE, especially when other risk factors were present. The threshold TSB level that identified 90% of infants with ABE/BE was 25.4 mg/dL when neurotoxicity risk factors were present. In contrast, neurotoxicity was first observed at a TSB level of >31.5 mg/dL in 111 infants without risk factors.

CONCLUSIONS

Newborns without risk factors for neurotoxicity have a higher tolerance for hyperbilirubinemia than recognized in management guidelines. The risk for BE in hemolytic disease varies with etiology. The great variation in response to TSB indicates that biological factors other than TSB values are important in the pathogenesis of BE.

Severe neonatal hyperbilirubinemia and kernicterus: are these still problems in the third millennium?

Despite efforts to eliminate permanent and irreversible brain damage due to bilirubin encephalopathy and kernicterus, these conditions continue to accompany us into the third millennium. This phenomenon occurs not only in developing countries with emerging medical systems, but in Westernized countries as well. Comprehensive guidelines to detect newborns with jaundice and treat those in whom hyperbilirubinemia has already developed have been formulated in several countries, but have not been successful in completely eliminating the problem. In this appraisal of the situation we review selected aspects of bilirubin encephalopathy and/or kernicterus. We highlight recent reports of severe hyperbilirubinemia and kernicterus, discuss some of the factors responsible for the continuing appearance of these conditions, and briefly review what can be done to decrease bilirubin-related morbidity and mortality to the minimum.