Predictive and diagnostic measures for kernicterus spectrum disorder: a prospective cohort study.

BACKGROUND: Kernicterus spectrum disorder (KSD) resulting from neonatal hyperbilirubinemia remains a common cause of cerebral palsy worldwide. This 12-month prospective cohort study followed neonates with hyperbilirubinemia to determine which clinical measures best predict KSD. METHODS: The study enrolled neonates ≥35 weeks gestation with total serum bilirubin (TSB) ≥ 20 mg/dl admitted to Aminu Kano Hospital, Nigeria. Clinical measures included brain MRI, TSB, modified bilirubin-induced neurologic dysfunction (BIND-M), Barry-Albright Dystonia scale (BAD), auditory brainstem response (ABR), and the modified KSD toolkit. MRI signal alteration of the globus pallidus was scored using the Hyperbilirubinemia Imaging Rating Tool (HIRT). RESULTS: Of 25 neonates enrolled, 13/25 completed 12-month follow-up and six developed KSD. Neonatal BIND-M ≥ 3 was 100% sensitive and 83% specific for KSD. Neonatal ABR was 83% specific and sensitive for KSD. Neonatal HIRT score of 2 was 67% sensitive and 75% specific for KSD; this increased to 100% specificity and sensitivity at 12 months. BAD ≥ 2 was 100% specific for KSD at 3-12 months, with 50-100% sensitivity. CONCLUSIONS: Neonatal MRIs do not reliably predict KSD. BIND-M is an excellent screening tool for KSD, while the BAD or HIRT score at 3 or 12 months can confirm KSD, allowing for early diagnosis and intervention. IMPACT: The first prospective study of children with acute bilirubin encephalopathy evaluating brain MRI findings over the first year of life. Neonatal MRI is not a reliable predictor of kernicterus spectrum disorders (KSD). Brain MRI at 3 or 12 months can confirm KSD. The modified BIND scale obtained at admission for neonatal hyperbilirubinemia is a valuable screening tool to assess risk for developing KSD. The Barry Albright Dystonia scale and brain MRI can be used to establish a diagnosis of KSD in at-risk infants as early as 3 months.

Magnetic resonance spectroscopy and auditory brain-stem response audiometry as predictors of bilirubin-induced neurologic dysfunction in full-term jaundiced neonates.

The purpose of this research was to define the functions of MRS and ABR as predictors of bilirubin-induced neurologic dysfunction (BIND) in full-term neonates who required intervention (phototherapy and/or exchange transfusion). This prospective cohort study was done at the NICU of Tanta University Hospitals over a 2-year duration. Fifty-six full-term neonates with pathological unconjugated hyperbilirubinemia were divided according to MRS and ABR findings into 2 groups: group (1) included 26 cases with mild acute bilirubin encephalopathy (BIND-M score 1-4). Group (2) included 30 cases with neonatal hyperbilirubinemia only. In addition, 20 healthy neonates with similar ages were employed as the controls. When compared to group 2 and the control group, group 1's peak-area ratios of NAA/Cr and NAA/Cho were found to be significantly reduced (P < 0.05). As compared to group 2 and the control group, group 1's Lac/Cr ratio was significantly greater (P < 0.05), but the differences were not significant for group 2 when compared to the control group. Waves III and V peak latencies, I-III, and I-V interpeak intervals were significantly prolonged in group 1 in comparison to group 2 and controls (P < 0.05) with no significant difference between group 2 and control group.   Conclusion: When the symptoms of ABE are mild and MRI does not show any evident abnormalities, MRS and ABR are helpful in differentiating individuals with ABE from patients with neonatal hyperbilirubinemia.    Trial registration:  ClinicalTrials.gov , Identifier: NCT06018012. What is Known: • MRS can be used as a diagnostic and prognostic tool for the differential diagnosis of patients with acute bilirubin encephalopathy, from patients with neonatal hyperbilirubinemia What is New: • ABR is a useful diagnostic and prognostic tool in the care and management of neonates with significantly raised bilirubin. It can be used as early predictor of acute bilirubin encephalopathy in the earliest stage of auditory damage caused by bilirubin.

Unbound Bilirubin and Acute Bilirubin Encephalopathy in Infants Born Late Preterm and Term with Significant Hyperbilirubinemia.

OBJECTIVE: To compare the association of unbound bilirubin (UB), total serum bilirubin (TSB), and bilirubin:albumin molar ratio (BAMR) with acute bilirubin encephalopathy (ABE), as assessed by bilirubin-induced neurologic dysfunction (BIND) score, in infants with significant hyperbilirubinemia (TSB ≥20 mg/dL or underwent exchange transfusion). STUDY DESIGN: In this prospective cohort study, infants ≥34 weeks of gestational age with significant hyperbilirubinemia during the first 2 postnatal weeks were eligible, unless they had craniofacial malformations, chromosomal disorders, TORCH (toxoplasmosis, other infections, rubella, cytomegalovirus and herpes simplex) infections, surgery, or a family history of congenital deafness. TSB, serum albumin, and UB were measured at hospital admission using the colorimetric, bromocresol green, and modified peroxidase method, respectively. Infants were evaluated on admission for ABE using a standardized neurologic examination and assigned a BIND score by trained physicians. Infants with a total BIND score of 0 were deemed to not have ABE, whereas those with a score ≥1 were deemed to have ABE. RESULTS: A total of 151 infants were studied, among whom 37 (24.5%) had ABE. Of these, 19 had mild ABE (BIND score 1-3) and 18 had moderate-to-severe ABE (BIND score 4-9). On logistic regression, UB, but not TSB or BAMR, was associated with ABE (aOR 1.64; 95% CI 1.17-2.3). On ordered logistic regression, UB, but not TSB or BAMR, was associated with severity of ABE (aOR 1.76; 95% CI 1.28-2.4). CONCLUSIONS: Our findings of the association between UB and ABE indicate that BIND scoring may be useful for evaluation of ABE in infants ≥34 weeks of gestational age.

Prospective cohort study of neurodevelopmental outcomes following extreme neonatal hyperbilirubinaemia in Australia.

AIM: This study aimed to establish the incidence and nature of neurodevelopmental outcomes following extreme neonatal hyperbilirubinaemia in an Australian cohort. METHODS: A prospective cohort study of neurodevelopmental outcomes up to 3 years of age of infants born between 2010 and 2013 at ≥34 weeks gestation, with total serum bilirubin ≥450 µmol/L and/or clinical signs of acute bilirubin encephalopathy. Outcome measures comprised neurological examination, Bayley Scales of Infant and Toddler Development, 3rd edition and Ages and Stages Questionnaire, 3rd edition. RESULTS: The Australian estimated incidence of kernicterus is 0.35 per 100 000 live births. Within the follow-up cohort of 26, three children have clinical neurodevelopmental impairment: one has gross motor function classification system level 4 cerebral palsy, audiological deficiency and visual impairment; the second has gross motor function classification system level 1 cerebral palsy and the third has global developmental delay with autism spectrum disorder. Mean Bayley Scales of Infant and Toddler Development, 3rd edition scores were: cognition 10.3 (SD 1.5), receptive communication 9.4 (SD 1.8), expressive communication 9.2 (SD 2.4), fine motor 10.4 (SD 2.6) and gross motor 9.2 (SD 2.3). CONCLUSION: The Australian national rate of kernicterus compares favourably with global estimates. Future preventative strategies in this context include universal neonatal hyperbilirubinaemia assessment and mandated adverse outcome reporting and investigation.

Neonatal Hyperbilirubinemia: Evaluation and Treatment.

Neonatal jaundice due to hyperbilirubinemia is common, and most cases are benign. The irreversible outcome of brain damage from kernicterus is rare (1 out of 100,000 infants) in high-income countries such as the United States, and there is increasing evidence that kernicterus occurs at much higher bilirubin levels than previously thought. However, newborns who are premature or have hemolytic diseases are at higher risk of kernicterus. It is important to evaluate all newborns for risk factors for bilirubin-related neurotoxicity, and it is reasonable to obtain screening bilirubin levels in newborns with risk factors. All newborns should be examined regularly, and bilirubin levels should be measured in those who appear jaundiced. The American Academy of Pediatrics (AAP) revised its clinical practice guideline in 2022 and reconfirmed its recommendation for universal neonatal hyperbilirubinemia screening in newborns 35 weeks' gestational age or greater. Although universal screening is commonly performed, it increases unnecessary phototherapy use without sufficient evidence that it decreases the incidence of kernicterus. The AAP also released new nomograms for initiating phototherapy based on gestational age at birth and the presence of neurotoxicity risk factors, with higher thresholds than in previous guidelines. Phototherapy decreases the need for an exchange transfusion but has the potential for short- and long-term adverse effects, including diarrhea and increased risk of seizures. Mothers of infants who develop jaundice are also more likely to stop breastfeeding, even though discontinuation is not necessary. Phototherapy should be used only for newborns who exceed thresholds recommended by the current AAP hour-specific phototherapy nomograms.

Kernicterus on the Spectrum.

Kernicterus is the potential toxic sequela of extreme neonatal hyperbilirubinemia resulting from the passage of excess free, unconjugated bilirubin across the blood-brain barrier, irreversibly and selectively damaging vulnerable target brain cells including the basal ganglia, the cerebellum, and the auditory system. Kernicterus continues to plague the modern world. Not only does it continue to be uncontrolled in developing countries with underdeveloped medical systems, and health organizations rendered ineffective by the ravages of war, but it also remains prevalent in industrialized countries. In this review, we attempt to clarify the different and overlapping nomenclature used in the past to describe this entity and aim to offer a uniform approach to defining kernicterus spectrum disorder. We also discuss the different spectrum subtypes including motor-predominant kernicterus, auditory neural sensory dysfunction, subtle kernicterus, and kernicterus plus. In addition to reviewing several genetic factors that increase the risk of developing kernicterus, we also present some exciting potential therapeutic approaches.

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The American Academy of Pediatrics updated the guidelines for the management of hyperbilirubinemia in the newborn infants with a gestational age of ≥35 weeks in September 2022. Based on the evidence over the past 18 years, the guidelines are updated from the aspects of the prevention, risk assessment, intervention, and follow-up of hyperbilirubinemia in the newborn infants with a gestational age of ≥35 weeks. This article gives an interpretation of the key points in the guidelines, so as to safely reduce the risk of bilirubin encephalopathy and unnecessary intervention.

Technical Report: Diagnosis and Management of Hyperbilirubinemia in the Newborn Infant 35 or More Weeks of Gestation.

CONTEXT: Severe hyperbilirubinemia is associated with kernicterus. Informed guidance on hyperbilirubinemia management, including preventive treatment thresholds, is essential to safely minimize neurodevelopmental risk. OBJECTIVE: To update the evidence base necessary to develop the 2022 American Academy of Pediatrics clinical practice guideline for management of hyperbilirubinemia in the newborn infant ≥35 weeks' gestation. DATA SOURCE: PubMed. STUDY SELECTION: English language randomized controlled trials and observational studies. Excluded: case reports or series, nonsystematic reviews, and investigations focused on <35-weeks' gestation infants. DATA EXTRACTION: Topics addressed in the previous clinical practice guideline (2004) and follow-up commentary (2009) were updated with new evidence published through March 2022. Evidence reviews were conducted for previously unaddressed topics (phototherapy-associated adverse effects and effectiveness of intravenous immune globulin [IVIG] to prevent exchange transfusion). RESULTS: New evidence indicates that neurotoxicity does not occur until bilirubin concentrations are well above the 2004 exchange transfusion thresholds. Systematic review of phototherapy-associated adverse effects found limited and/or inconsistent evidence of late adverse effects, including cancer and epilepsy. IVIG has unclear benefit for preventing exchange transfusion in infants with isoimmune hemolytic disease, with a possible risk of harm due to necrotizing enterocolitis. LIMITATIONS: The search was limited to 1 database and English language studies. CONCLUSIONS: Accumulated evidence justified narrowly raising phototherapy treatment thresholds in the updated clinical practice guideline. Limited evidence for effectiveness with some evidence of risk of harm support the revised recommendations to limit IVIG use.

Neonatal Hyperbilirubinemia.

Neonatal hyperbilirubinemia (NH) is a common phenomenon. In most cases, NH is benign and transient. However, in severe NH cases, neonates can develop encephalopathy and kernicterus. With appropriate screening and treatment, these adverse sequelae can be prevented. This article aims to provide the reader with an in-depth understanding of (1) bilirubin metabolism, (2) risk factors for severe NH, (3) NH screening and treatment, (4) various etiologies of severe NH, and (5) consequences of severe, untreated NH. [Pediatr Ann. 2022;51(6):e219-e227.].

Bilirubin Encephalopathy.

PURPOSE OF REVIEW: Hyperbilirubinemia is commonly seen in neonates. Though hyperbilirubinemia is typically asymptomatic, severe elevation of bilirubin levels can lead to acute bilirubin encephalopathy and progress to kernicterus spectrum disorder, a chronic condition characterized by hearing loss, extrapyramidal dysfunction, ophthalmoplegia, and enamel hypoplasia. Epidemiological data show that the implementation of universal pre-discharge bilirubin screening programs has reduced the rates of hyperbilirubinemia-associated complications. However, acute bilirubin encephalopathy and kernicterus spectrum disorder are still particularly common in low- and middle-income countries. RECENT FINDINGS: The understanding of the genetic and biochemical processes that increase the susceptibility of defined anatomical areas of the central nervous system to the deleterious effects of bilirubin may facilitate the development of effective treatments for acute bilirubin encephalopathy and kernicterus spectrum disorder. Scoring systems are available for the diagnosis and severity grading of these conditions. The treatment of hyperbilirubinemia in newborns relies on the use of phototherapy and exchange transfusion. However, novel therapeutic options including deep brain stimulation, brain-computer interface, and stem cell transplantation may alleviate the heavy disease burden associated with kernicterus spectrum disorder. Despite improved screening and treatment options, the prevalence of acute bilirubin encephalopathy and kernicterus spectrum disorder remains elevated in low- and middle-income countries. The continued presence and associated long-term disability of these conditions warrant further research to improve their prevention and management.

Outcome Analysis of Severe Hyperbilirubinemia in Neonates Undergoing Exchange Transfusion.

OBJECTIVE: Severe neonatal hyperbilirubinemia can cause neurological disability or mortality if not effectively managed. Exchange transfusion (ET) is an efficient treatment to prevent bilirubin neurotoxicity. The purpose of this study was to evaluate outcomes in severe neonatal hyperbilirubinemia with ET and to identify the potential risk factors for poor outcomes. METHODS: Newborns of ≥28 weeks of gestational age with severe hyperbilirubinemia who underwent ET from January 2015 to August 2019 were included. Demographic data were recorded and analyzed according to follow-up outcomes at 12 months of corrected age. Poor outcomes were defined as death due to bilirubin encephalopathy or survival with at least one of the following complications: cerebral palsy, psychomotor retardation (psychomotor developmental index < 70), mental retardation (mental developmental index < 70), or hearing impairment. RESULTS: A total of 524 infants were eligible for recruitment to the study, and 62 infants were lost to follow-up. The outcome data from 462 infants were used for grouping analysis, of which 398 cases (86.1%) had normal outcomes and 64 cases (13.9%) suffered poor outcomes. Bivariate logistic regression analysis showed that peak total serum bilirubin (TSB) (odds ratio [OR] = 1.011, 95% confidence interval [CI] = 1.008-1.015, p = 0.000) and sepsis (OR = 4.352, 95% CI = 2.013-9.409, p < 0.001) were associated with poor outcomes of hyperbilirubinemia. Receiver operator characteristic curve analysis showed that peak TSB ≥452.9 µmol/L could predict poor outcomes of severe hyperbilirubinemia. CONCLUSION: Peak TSB and sepsis were associated with poor outcomes in infants with severe hyperbilirubinemia, and peak TSB ≥452.9 µmol/L could predict poor outcomes.

Kernicterus Spectrum Disorders Diagnostic Toolkit: validation using retrospective chart review.

BACKGROUND: Kernicterus Spectrum Disorders (KSDs) result from hyperbilirubinemia-induced brain injury. We developed a Toolkit (KSD-TK) to predict the likelihood of KSDs. This study aims to validate the KSD-TK by comparing it to clinical diagnoses made by the Kernicterus Clinic in the Division of Neurology. METHODS: Through retrospective chart review, we completed a KSD-TK for 37 patients evaluated between 2011 and 2019 using highest bilirubin, newborn risk factors, neonatal exam, follow-up exam, auditory testing, tooth enamel, and MRI brain results. KSD-TK results were compared to the clinical diagnoses given by a kernicterus expert (SS). RESULTS: Of 37 patients, 29 were clinically diagnosed with kernicterus, including 14/14 with KSD-TK scored as "definite", 14/15 "probable", and 1/2 with "possible" kernicterus. None of 6 patients with KSD-TK "not kernicterus" were clinically diagnosed with kernicterus. Combining KSD-TK "definite" and "probable", the KSD-TK has 96.6% sensitivity and 87.5% specificity. Each KSD-TK component had high sensitivity, but only three had specificity ≥0.75: auditory neuropathy spectrum disorder, abnormal movements and/or tone on follow-up exam, and abnormal globus pallidus and/or subthalamic nucleus on MRI. CONCLUSION: The KSD-TK is a promising screening tool for patients at risk for kernicterus. IMPACT: This study provides validation of a Kernicterus Spectrum Disorders (KSDs) Toolkit. The toolkit provides screening criteria for predicting KSD diagnosis. Scores of definite or probable have high sensitivity and specificity for KSDs. Abnormal auditory processing, exam, and MRI were most specific for KSDs.

Neonatal hyperbilirubinemia and bilirubin neurotoxicity in hospitalized neonates: analysis of the US Database.

OBJECTIVE: The objective of this study was to assess the prevalence and trends for neonatal hyperbilirubinemia, and the development of bilirubin neurotoxicity in the USA. STUDY DESIGN: We used a de-identified national dataset for the years 2002-2017. The study included all newborn inpatients with postnatal age ≤28 days. Cochran-Armitage trend test was used for trend analyses. Regression analyses were performed and adjusted odds ratios (aOR) were reported. RESULTS: The study included 57,989,476 infants; of them 53,259,758 (91.8%) were term infants and 4,725,178 (8.2%) were preterm infants. Bilirubin neurotoxicity decreased over the years in term infants (Z = 0.36, p = 0.03) without change in preterm infants (Z = 42.5, p = 0.12). Black neonates were less likely to be diagnosed with hyperbilirubinemia than White neonates (aOR = 0.77, 95% confidence interval (CI): 0.77-0.78, p < 0.001) and more likely to develop bilirubin neurotoxicity than White neonates (aOR = 3.0.5, 95% CI: 2.13-4.36, p < 0.001). Bilirubin neurotoxicity rate in the overall population was 2.4 per 100,000 live births. CONCLUSIONS: Bilirubin neurotoxicity has significantly decreased in term infants and did not change in preterm infants. Despite the less diagnosis of hyperbilirubinemia in Black newborns, they are disproportionately at increased risk of developing bilirubin neurotoxicity when compared to White newborns. IMPACT: In this article, we analyzed the National Inpatient Database. This is the largest study of its kind using data on 57,989,476 neonates. The article has multiple novel findings: (1) it demonstrated that utilization of phototherapy has increased significantly over the years, (2) the rate of kernicterus for neonates decreased in term infants and did not change in preterm babies, (3) kernicterus was mostly encountered in infants without isoimmunization jaundice, and (4) there is a clear racial disparity in neonatal jaundice; although Black newborns have less neonatal jaundice, they are at increased risk of developing kernicterus.

Early Neurodevelopmental Outcome of Neonates with Gestation 35 Weeks or More with Serum Bilirubin in Exchange Range Without Encephalopathy: A Prospective Observational Study.

OBJECTIVE: To describe early neurodevelopment outcomes of neonates with severe hyperbilirubinemia without acute bilirubin encephalopathy (ABE). METHODS: Neonates born at gestation ≥35 weeks, admitted to NICU with total serum bilirubin (TSB) in exchange range with no features of ABE, were followed up until the age of 6 months. Infants were assessed for impaired hearing and neurodevelopment at 3 months and 6 months of age. RESULTS: A total of 59 neonates were enrolled in the study. At 3 months of age, 7.6 percent of neonates were found to have hypotonia and motor delay, whereas 42.3 percent had abnormal brainstem evoked response audiometery. At 6 months, 6.4 percent of neonates were found to have persistent neurodevelopmental impairment. CONCLUSION: Severe hyperbilirubinemia is associated with impaired neurodevelopment and hearing even in infants without ABE. Peak TSB level strongly correlates with abnormal outcomes.

Neonatal Jaundice in Preterm Infants with Bilirubin Encephalopathy.

INTRODUCTION: The aim of this study is to clarify bilirubin parameters and its treatment in preterm infants with bilirubin encephalopathy (pBE). METHODS: We asked the responders to an earlier nationwide Japanese survey on pBE to provide additional information. pBE was diagnosed based on the criteria used in the nationwide survey. We collected data on serum total bilirubin (TB), direct bilirubin (DB), albumin, and unbound bilirubin (UB) levels during the first 8 weeks of life, and on phototherapy and exchange transfusion treatments. RESULTS: We obtained clinical data from 75 patients with pBE from 58 hospitals (response rate of 59%), who were born between 2002 and 2016. The average peak TB level was 12.6 mg/dL (215 µmol/L), and the average age at peak attainment was 19.7 days after birth. Albumin level was <2.5 g/dL in 44 patients, and the peak DB level was ≥2 mg/dL (34.2 µmol/L) in 20 patients. The average peak bilirubin/albumin (B/A) (mg/g) ratio was 3.8 (molar ratio of 0.475), and the average age at peak attainment was 18.6 days. The average peak UB level was 0.67 µg/dL (11.5 nmol/L). The median duration of phototherapy was 6 days, and the median day of the last session was 12. The peak TB level occurred after the last day of phototherapy in 30 of the 61 patients available for comparison. CONCLUSIONS: Most patients with pBE lacked marked elevations in serum TB levels and the B/A ratio, the peaks of which were sometimes delayed to >4 weeks after birth.

Acute bilirubin encephalopathy: Some lessons learned.

Acute bilirubin encephalopathy (ABE) is still an insufficiently addressed cause of mortality and long-term morbidity in low- and middle-income countries (LMICs). This article highlights that delayed or incorrect medical advice, inaccurate bilirubin measurements as well as ineffective phototherapy are some of the relevant causes predisposing jaundiced newborns to develop extreme hyperbilirubinemia [EHB, total serum/plasma bilirubin (TB) ≥ 25 mg/dL (428 µmol/L)] and subsequent ABE. Obstacles preventing state of the art management of such infants are also discussed. Prevention of ABE cannot occur without a system-based approach tailored to suit the needs and available resources of each community. Clear set protocols, rigorous training, monitoring, and accurate documentation together with simple innovative affordable technologies that can be locally produced, are essential to observe the change desired.

Neonatal Hyperbilirubinemia: An Updated Appraisal of National Guidelines.

Recent reports from several developed countries have documented a resurgence of bilirubin encephalopathy causing both healthcare and forensic issues. For these reasons, many national pediatric societies have issued recommendations on the diagnosis and the treatment of clinically significant neonatal hyperbilirubinemia. The differences among individual national documents may have an impact on neonatal healthcare. This paper shortly reviews the advantages and the shortcomings of the main international guidelines with a focus on the available evidence.