Screening and follow-up for neonatal hyperbilirubinemia: a review

Activation of Alternative Bilirubin Clearance Pathways Partially Reduces Hyperbilirubinemia in a Mouse Model Lacking Functional Ugt1a1 Activity

Bilirubin is a heme catabolite and Ugt1a1 is the only enzyme involved in the biological elimination of bilirubin. Partially functional or non-functional Ugt1a1 may result in neuronal damage and death due to the accumulation of unconjugated bilirubin in the brain. The understanding of the role of alternative bilirubin detoxification mechanisms that can reduce bilirubin toxicity risk is crucial for developing novel therapeutic strategies. To provide a proof-of-principle showing whether activation of alternative detoxification pathways could lead to life-compatible bilirubin levels in the absence of Ugt1a1 activity, we used Ugt1^−/− hyperbilirubinemic mice devoid of bilirubin glucuronidation activity. We treated adult Ugt1^−/− mice with TCPOBOP, a strong agonist of the constitutive androstane receptor (CAR). TCPOBOP treatment decreased plasma and liver tissue bilirubin levels by about 38%, and resulted in the transcriptional activation of a vast array of genes involved in bilirubin transport and metabolism. However, brain bilirubin level was unaltered. We observed ~40% degradation of bilirubin in the liver microsomes from TCPOBOP treated Ugt1^−/− mice. Our findings suggest that, in the absence of Ugt1a1, the activation of alternative bilirubin clearance pathways can partially improve hyperbilirubinemic conditions. This therapeutic approach may only be considered in a combinatorial manner along with other treatments.

Increased Total Serum Bilirubin Level Post-Ibuprofen Use Is Inversely Correlated with Neonates' Body Weight

Backgrounds: Drugs with the ability to displace bilirubin from albumin-binding sites subsequently leading to an increased bilirubin level may cause hyperbilirubinemia in neonates. Ibuprofen is commonly used to treat patent ductus arteriosus (PDA) in neonates, yet the use of ibuprofen has drawn mixed conclusions. We performed a retrospective study to determine how ibuprofen use influences the total serum bilirubin (TSB) level in neonates of differing birth weight (BW). Materials and methods: Neonates (including premature infants) born at Chang Gung Memorial Hospital, Taiwan during January 2004 to July 2020 were entered into this study. We recorded the phototherapy duration, including the initial day and end day, and determined the average influence of one-day phototherapy on TSB level. The highest monitored TSB level post-ibuprofen use minus the one measured prior to ibuprofen use was considered the TSB change following ibuprofen administration in this study, and the above-mentioned influence of daily phototherapy on the TSB level was used to correlate the results. Neonates with any of the following conditions were excluded: those who received ceftriaxone, those with intraventricular hemorrhage, and those infected with TORCH. Results: The average daily influence of phototherapy on the TSB level of neonates was −0.20 (−0.57~0.05) mg/dL, −0.28 (−0.84~0.13) mg/dL, −0.75 (−1.77~0.10) mg/dL, and −1.60 (−2.70~−0.50) mg/dL in neonates with BWs of <1 kg, 1−1.49 kg, 1.5−2.49 kg, and ≥2.5 kg, respectively, indicating that neonates with a BW ≥ 1.5 kg experienced a greater reduction in TSB level following phototherapy as compared with those with a BW < 1.5 kg. The average TSB increase following ibuprofen use in neonates was 3.38 ± 2.77 mg/dL, 2.04 ± 2.53 mg/dL, and 1.34 ± 2.24 mg/dL in neonates with BWs of <1 kg, 1−1.49 kg, and ≥1.5 kg, respectively, i.e., an elevated TSB change with a decreased neonate BW was noted post-ibuprofen use (p = 0.026, one-way analysis of variance (ANOVA)). Conclusions: As ibuprofen use is correlated with an apparent increase in TSB level in neonates with a lower BW, especially in those with a BW < 1 kg, iv acetaminophen can be an appropriate alternative to ibuprofen for ELBW neonates for the treatment of PDA if they are experiencing severe unconjugated hyperbilirubinemia.

Immunohematology testing using umbilical cord blood: review of the literature, survey of practice and guidance development

BACKGROUND

Following delivery, blood tests are performed on umbilical cord blood (CB) to avoid neonatal venipuncture. Despite widespread and longstanding CB testing, no guidelines exist to suggest which immunohematology tests should be performed on CB.

STUDY DESIGN AND METHODS

We performed a scoping review, surveyed national practice, and developed guidance statements concerning CB testing. Database searches identified relevant articles. A survey was sent to all Canadian hospitals and transfusion laboratories that perform perinatal testing. A national panel of experts was convened to develop guidance statements.

RESULTS

A total of 116 articles met the inclusion criteria and were summarized. Literature on CB testing is limited; few studies have investigated laboratory testing methodologies or validated CB test results with peripheral samples. The survey was completed by 580/597 institutions (97%); 85% were community hospitals and 16% had a neonatal intensive care unit. There is diversity in the types of CB tests performed and variability in practice. While most centers order appropriately, some laboratories routinely perform CB tests that are not clinically indicated (e.g., direct antiglobulin testing for all neonates) and other do not perform CB tests when results would be beneficial (e.g., phenotype on CB when mother has a clinically significant antibody). Fifteen guidance statements were developed.

DISCUSSION

This study highlights variability in CB testing, likely reflecting evidence gaps, methodology differences between studies, and lack of guidelines. CB tests should only be performed when indicated and validated on this sample type. The presented guidance statements aim to standardize practice and encourage judicious CB sampling.

Current and emerging technologies for the timely screening and diagnosis of neonatal jaundice

Neonatal jaundice is one of the most common clinical conditions affecting newborns. For most newborns, jaundice is harmless, however, a proportion of newborns develops severe neonatal jaundice requiring therapeutic interventions, accentuating the need to have reliable and accurate screening tools for timely recognition across different health settings. The gold standard method in diagnosing jaundice involves a blood test and requires specialized hospital-based laboratory instruments. Despite technological advancements in point-of-care laboratory medicine, there is limited accessibility of the specialized devices and sample stability in geographically remote areas. Lack of suitable testing options leads to delays in timely diagnosis and treatment of clinically significant jaundice in developed and developing countries alike. There has been an ever-increasing need for a low-cost, simple to use screening technology to improve timely diagnosis and management of neonatal jaundice. Consequently, several point-of-care (POC) devices have been developed to address this concern. This paper aims to review the literature, focusing on emerging technologies in the screening and diagnosing of neonatal jaundice. We report on the challenges associated with the existing screening tools, followed by an overview of emerging sensors currently in pre-clinical development and the emerging POC devices in clinical trials to advance the screening of neonatal jaundice. The benefits offered by emerging POC devices include their ease of use, low cost, and the accessibility of rapid response test results. However, further clinical trials are required to overcome the current limitations of the emerging POC's before their implementation in clinical settings. Hence, the need for a simple to use, low-cost POC jaundice detection technology for newborns remains an unsolved challenge globally.

Long-Term Effects of Biliverdin Reductase a Deficiency in Ugt1-/- Mice: Impact on Redox Status and Metabolism

Accumulation of neurotoxic bilirubin due to a transient neonatal or persistent inherited deficiency of bilirubin glucuronidation activity can cause irreversible brain damage and death. Strategies to inhibit bilirubin production and prevent neurotoxicity in neonatal and adult settings seem promising. We evaluated the impact of Bvra deficiency in neonatal and aged mice, in a background of unconjugated hyperbilirubinemia, by abolishing bilirubin production. We also investigated the disposal of biliverdin during fetal development. In Ugt1^−/− mice, Bvra deficiency appeared sufficient to prevent lethality and to normalize bilirubin level in adults. Although biliverdin accumulated in Bvra-deficient fetuses, both Bvra^−/− and Bvra^−/−Ugt1^−/− pups were healthy and reached adulthood having normal liver, brain, and spleen histology, albeit with increased iron levels in the latter. During aging, both Bvra^−/− and Bvra^−/−Ugt1^−/− mice presented normal levels of relevant hematological and metabolic parameters. Interestingly, the oxidative status in erythrocytes from 9-months-old Bvra^−/− and Bvra^−/−Ugt1^−/− mice was significantly reduced. In addition, triglycerides levels in these 9-months-old Bvra^−/− mice were significantly higher than WT controls, while Bvra^−/−Ugt1^−/− tested normal. The normal parameters observed in Bvra^−/−Ugt1^−/− mice fed chow diet indicate that Bvra inhibition to treat unconjugated hyperbilirubinemia seems safe and effective.

Combating the Hidden Health Disparity of Kernicterus in Black Infants: A Review

IMPORTANCE

Kernicterus is a devastating, permanently disabling neurologic condition resulting from bilirubin neurotoxicity. Black neonates account for more than 25% of kernicterus cases in the US, despite making up only approximately 14% of all births. This is a largely overlooked health disparity.

OBSERVATIONS

The black kernicterus health disparity exists despite a lower overall incidence of clinically significant hyperbilirubinemia among black neonates, a paradox recently explained by a previously unrecognized risk for hazardous hyperbilirubinemia. Aligned with national and global health initiatives to reduce or eliminate health disparities, this review highlights the multiple biologic and nonbiologic factors contributing to kernicterus risk in black infants and approaches to reduce this health disparity. This includes both parent-level and clinician-level kernicterus prevention strategies, with an emphasis on improving parental health literacy on neonatal jaundice and acute bilirubin encephalopathy and clinician awareness of the key factors that contribute to hazardous hyperbilirubinemia risk in this vulnerable group. Parent-level prevention strategies include efforts to improve their health literacy on neonatal jaundice and acute bilirubin encephalopathy and empower care seeking for jaundice. Clinician-level prevention strategies include efforts to eliminate community and institutional barriers that impede access to care, heighten clinician awareness of the factors that contribute to kernicterus risk in this vulnerable patient group, and strengthen newborn hyperbilirubinemia management and bilirubin surveillance.

CONCLUSIONS AND RELEVANCE

There are multiple opportunities for intervention to reduce black kernicterus risk. Although kernicterus is a rare disorder, the incidence among black infants is not a trivial matter nor are efforts to prevent kernicterus. While the multiple interacting biologic and nonbiologic contributors to increased kernicterus risk among black infants pose a considerable challenge to clinicians, there are opportunities for intervention to reduce this risk and health disparity. Continued study is imperative to understand the current scope of kernicterus and its occurrence in black neonates.

[An investigation of severe neonatal hyperbilirubinemia in 13 hospitals of Jiangsu Province, China]

OBJECTIVE

To investigate the incidence of severe neonatal hyperbilirubinemia and the management on the treatment and follow-up of this disease in Jiangsu Province, China.

METHODS

The neonates with severe hyperbilirubinemia who were admitted to 13 hospitals in Jiangsu Province from January to December, 2018, were enrolled as subjects. A retrospective analysis was performed on their mediacal data and follow-up data.

RESULTS

In 2018, 740 neonates with severe hyperbilirubinemia were reported from the 13 hospitals in Jiangsu Province, accounting for 2.70% (740/27 386) of the total number of neonates admitted to the department of neonatology. Among these neonates, 620 (83.8%) had severe hyperbilirubinemia, 106 (14.3%) had extremely severe hyperbilirubinemia, and 14 (1.9%) had hazardous hyperbilirubinemia. Four neonates (0.5%) were diagnosed with acute bilirubin encephalopathy. A total of 484 neonates (65.4%) were readmitted due to severe hyperbilirubinemia after discharge from the delivery institution, with a median age of 7 days, among whom 214 (44.2%) were followed up for jaundice at the outpatient service before readmission, with a median age of 6 days at the first time of outpatient examination. During hospitalization, 211 neonates (28.5%) underwent cranial MRI examinations, among whom 85 (40.3%) had high T1WI signal in the bilateral basal ganglia and the globus pallidus; 238 neonates (32.2%) underwent brainstem auditory evoked potential examinations, among whom 14 (5.9%) passed only at one side and 7 (2.9%) failed at both sides. The 17 neonates with acute bilirubin encephalopathy or hazardous hyperbilirubinemia were followed up. Except one neonate was lost to follow-up, and there were no abnormal neurological symptoms in the other neonates.

CONCLUSIONS

Neonates with severe hyperbilirubinemia account for a relatively high proportion of the total number of neonates in the department of neonatology. Jaundice monitoring and management after discharge from delivery institutions need to be strengthened. For neonates with severe hyperbilirubinemia, relevant examinations should be carried out more comprehensively during hospitalization and these neonates should be followed up comprehensively and systematically after discharge.

Air pollution exposure associates with increased risk of neonatal jaundice

Clinical experience suggests increased incidences of neonatal jaundice when air quality worsens, yet no studies have quantified this relationship. Here we reports investigations in 25,782 newborns showing an increase in newborn's bilirubin levels, the indicator of neonatal jaundice risk, by 0.076 (95% CI: 0.027-0.125), 0.029 (0.014-0.044) and 0.009 (95% CI: 0.002-0.016) mg/dL per μg/m3 for PM2.5 exposure in the concentration ranges of 10-35, 35-75 and 75-200 μg/m3, respectively. The response is 0.094 (0.077-0.111) and 0.161 (0.07-0.252) mg/dL per μg/m3 for SO2 exposure at 10-15 and above 15 μg/m3, respectively, and 0.351 (0.314-0.388) mg/dL per mg/m3 for CO exposure. Bilirubin levels increase linearly with exposure time between 0 and 48 h. Positive relationship between maternal exposure and newborn bilirubin level is also quantitated. The jaundice-pollution relationship is not affected by top-of-atmosphere incident solar irradiance and atmospheric visibility. Improving air quality may therefore be key to lowering the neonatal jaundice risk.

Sensitivity, Specificity, and Accuracy of Kramer Examination of Neonatal Jaundice: Comparison with Total Bilirubin Serum

Neonatal jaundice often occurs in the first week after birth. Early detection of neonatal jaundice can prevent kernicterus as a complication of high levels of bilirubin in neonates. Visual assessment is one of the examinations introduced by Kramer to assess the presence of neonatal jaundice. The purpose of this study was to determine the sensitivity, specificity, and accuracy of Kramer's visual assessment in the examination of neonatal jaundice. This study used cross-sectional design to examine 102 infants, with the sample selected by the convenience sampling method. A 2 × 2 table diagnostic test was employed in this study to analyze the data. The results of this study showed that visual assessment of neonatal jaundice obtained a sensitivity value of 76.92%, a specificity value of 89.47%, and an accuracy value of 86.27%. This research can contribute to the development of other non-invasive methods for assessing neonatal jaundice, and thereby contribute to a decrease in neonatal morbidity.

Effectiveness of universal hyperbilirubinemia screening on newborn health: a systematic review protocol

REVIEW QUESTION/OBJECTIVE

The objective of this review is to assess the effectiveness of the universal hyperbilirubinemia screening program on common newborn health outcomes.Specifically, the review will assess: the incidence of severe hyperbilirubinemia/kernicterus/exchange transfusion, rate of readmission due to jaundice, length of hospital stay on birth admission, rate and utilization of phototherapy during birth hospitalization, and jaundice related emergency visits.

Albumin administration prevents neurological damage and death in a mouse model of severe neonatal hyperbilirubinemia

Therapies to prevent severe neonatal unconjugated hyperbilirubinemia and kernicterus are phototherapy and, in unresponsive cases, exchange transfusion, which has significant morbidity and mortality risks. Neurotoxicity is caused by the fraction of unconjugated bilirubin not bound to albumin (free bilirubin, Bf). Human serum albumin (HSA) administration was suggested to increase plasma bilirubin-binding capacity. However, its clinical use is infrequent due to difficulties to address its potential preventive and curative benefits, and to the absence of reliable markers to monitor bilirubin neurotoxicity risk. We used a genetic mouse model of unconjugated hyperbilirubinemia showing severe neurological impairment and neonatal lethality. We treated mutant pups with repeated HSA administration since birth, without phototherapy application. Daily intraperitoneal HSA administration completely rescued neurological damage and lethality, depending on dosage and administration frequency. Albumin infusion increased plasma bilirubin-binding capacity, mobilizing bilirubin from tissues to plasma. This resulted in reduced plasma Bf, forebrain and cerebellum bilirubin levels. We showed that, in our experimental model, Bf is the best marker to determine the risk of developing neurological damage. These results support the potential use of albumin administration in severe acute hyperbilirubinemia conditions to prevent or treat bilirubin neurotoxicity in situations in which exchange transfusion may be required.

Safe and symptomatic medicinal use of surface-functionalized Mn3O4 nanoparticles for hyperbilirubinemia treatment in mice

Aim: Testing the potential of citrate-capped Mn3O4 nanoparticles (NPs) as a therapeutic agent for alternative rapid treatment of hyperbilirubinemia through direct removal of bilirubin (BR) from blood in mice. Materials & methods: NPs were synthesized and the mechanism of BR degradation in presence and absence of biological macromolecules were characterized in vitro. To test the in vivo BR degradation ability of NPs, CCl4-intoxicated mice were intraperitoneally injected with NPs. Results: We demonstrated ultrahigh efficacy of the NPs in symptomatic treatment of hyperbilirubinemia for rapid reduction of BR in mice compared with conventional medicine silymarin without any toxicological implications. Conclusion: These findings may pave the way for practical clinical use of the NPs as safe medication of hyperbilirubinemia in human subjects.

How to use: transcutaneous bilirubinometry

The National Institute for Health and Clinical Excellence neonatal jaundice guidelines recommend checking the bilirubin level in all infants with visible jaundice. The gold standard for this measurement is total serum bilirubin (TSB). Transcutaneous bilirubinometry (TcB) is an alternative to TSB that has been validated for clinical use through extensive study. TcB provides many advantages over TSB including instantaneous measurements without requiring a painful lab draw. For infants >35&emsp14;weeks gestation, TcB can reliably identify infants at risk for severe hyperbilirubinaemia and can decrease the number of TSB measurements obtained. However, paediatric providers should be aware of limitations in clinical use of TcB including decreasing accuracy at higher bilirubin levels, lack of independently validated nomograms for interpretation and limited research regarding its use during phototherapy.

Total serum bilirubin exceeding exchange transfusion thresholds in the setting of universal screening

OBJECTIVE

To describe the incidence and predictors of total serum bilirubin (TSB) levels that meet or exceed American Academy of Pediatrics (AAP) exchange transfusion (ET) thresholds in the setting of universal screening.

STUDY DESIGN

We conducted a retrospective cohort analysis of electronic data on 18 089 newborns ≥35 weeks gestation born at Northern California Kaiser Permanente Medical Care Program hospitals implementing universal TSB screening in 2005 to 2007, with chart review for subjects with TSB levels reaching the AAP threshold for ET.

RESULTS

The outcome developed in 22 infants (0.12%); 14 (63.6%) were <38 weeks gestation. Only one infant received an ET; none of the infants had documented sequelae. The first TSB was at least high-intermediate risk on the AAP risk-nomogram for all 22 infants and high-risk for those ≥38 weeks, but was less than the phototherapy level in 15 infants (68%). Of these 15 infants, 2 failed phototherapy and 13 did not have a TSB repeated in <24 hours. However, re-testing all infants at high-intermediate risk or greater would have required 2166 additional bilirubin tests.

CONCLUSION

Screening was sensitive but not specific for predicting exchange threshold.