Audiologic impairment associated with bilirubin-induced neurologic damage

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.

Globus pallidus/putamen T1WI signal intensity ratio in grading and predicting prognosis of neonatal acute bilirubin encephalopathy

Purpose

This study sought to investigate the relationship between the globus pallidus/putamen T1 weighted image (T1WI) signal intensity ratio (G/P ratio) and the acute bilirubin encephalopathy (ABE) in neonates, and to develop a new strategy for the grading and prognosis of ABE based on the G/P ratio.

Methods

A total of 77 full-term neonates with ABE were scored according to bilirubin-induced neurological dysfunction and divided into mild, moderate, and severe groups. Cranial magnetic resonance imaging examinations were performed and the G/P ratio was recorded. The follow-up reexaminations were carried out at 6 months, 1 year, and 2 years after the initial examination. The neonates were then divided into two groups, the good prognosis group and the kernicterus spectrum disorder (KSD) group, according to the evaluation of Gesell Developmental Schedules and Brainstem Audio Electric Potential at 6 months.

Main findings

The differences of G/P ratios were statistically significant, not only among the mild, moderate, and severe ABE groups for the initial examinations but also between the KSD and the good prognosis groups for the follow-up reexaminations. Therefore, the ABE grading model and prognosis predicting model could be established based on the G/P ratio. In the KSD group, the area under the receiver operating characteristic curve of the G/P ratio-based predicting model was 93.5%, the optimal critical point was 1.29, the sensitivity was 88.2%, and the specificity was 93.3%.

Conclusions

The G/P ratio can be used as an indicating parameter for both the clinical grading of neonatal ABE and the assessment of neonatal ABE prognosis. Specifically, the G/P ratio greater than 1.29 indicates a KSD of neonatal ABE.

Hyperbilirubinemia Among Infants Born Preterm: Peak Levels and Association with Neurodevelopmental Outcomes

OBJECTIVE

To describe the distribution of peak bilirubin levels among infants born before 29 weeks of gestation in the first 14 days of life and to study the association between quartiles of peak bilirubin levels at different gestational ages and neurodevelopmental outcomes.

STUDY DESIGN

Multicenter, retrospective, nationwide cohort study of neonatal intensive care units in the Canadian Neonatal Network and Canadian Neonatal Follow-Up Network, including neonates born preterm at 220/7 to 286/7 weeks of gestation born between 2010 and 2018. Peak bilirubin levels were recorded during the first 14 days of age. Main outcome was significant neurodevelopmental impairment, defined as cerebral palsy with Gross Motor Function Classification System ≥3, or Bayley III-IV scores of <70 in any domain, or visual impairment, or bilateral hearing loss requiring hearing aids.

RESULTS

Among 12 554 included newborns, median gestational age was 26 weeks (IQR 25-28) and birth weight was 920 g (IQR 750-1105 g). The median peak bilirubin values increased as gestational age increased (112 mmol/L [6.5 mg/dL] at 22 weeks and 156 mmol/L [9.1 mg/dL] at 28 weeks). Significant neurodevelopmental impairment was identified in 1116 of 6638 (16.8%) of children. Multivariable analyses identified an association between peak bilirubin in the highest quartile and neurodevelopmental impairment (aOR 1.27, 95% CI 1.01-1.60) and receipt of hearing aid/cochlear implant (aOR 3.97, 95%CI: 2.01-7.82) compared with the lowest quartile.

CONCLUSION

In this multicenter cohort study, peak bilirubin levels in neonates of <29 weeks of gestation increased with gestational age. Peak bilirubin values in the highest gestational age-specific quartile were associated with significant neurodevelopmental and hearing impairments.

Hyperbilirobinemia and Its Effect on Auditory Perception and Speech Intelligibility in Cochlear Implanted Children (Cochlear Implantation Outcomes in Children Who Have Experienced Hyperbilirobinemia)

The goal of this study was to investigate the probable difference in auditory perception and speech intelligibility performance amongst cochlear implanted children who experienced hyperbilirubinemia or auditory neuropathy in comparison to the cochlear implanted children with unknown etiology for hearing loss. This case-control study was carried out on 106 cochlear implanted children with mean age of 32.36 ± 11.98 months who were purposively selected and allocated into four groups. Out of the total, 30 had no specific etiology for hearing loss, while the others had experienced auditory neuropathy or hyperbilirubinemia with/without blood exchange. The auditory perception and speech intelligibility performance of all the participants who had received auditory verbal therapy were assessed after 6 and 12 months of rehabilitation. Then, the data was analyzed, using the Statistical Package for Social Sciences-version 21(SPSS-21). Results indicated poor auditory perception and speech intelligibility performance of the cochlear implanted children with hyperbilirubinemia and blood exchange (P ≤ 0.05), while the participants in the control group with no specific etiology for hearing loss, the children with hyperbilirubinemia with no blood exchange, and those who suffered from auditory neuropathy performed better, respectively. Also, a significant correlation between auditory neuropathy and hyperbilirubinemia was observed. Despite lower improvement of auditory perception and speech intelligibility of the hearing impaired children who were experiencing moderate to severe degrees of hyperbilirubinemia or auditory neuropathy, cochlear implantation is highly recommended not only for children with unknown etiology for severe hearing loss but also for this group of hearing impaired children.

Surface plasmon-enhanced fluorescence and surface-enhanced Raman scattering dual-readout chip constructed with silver nanowires: Label-free clinical detection of direct-bilirubin

It has been found that the direct/total bilirubin ratio (D/T-BIL) is related to the survival rate of COVID-19 pneumonia. The presence of an excessive amount of bilirubin in human blood also causes liver and neurological damage, leading to death. Therefore, upon considering the adverse impact of the presence of excessive bilirubin in human blood, it has become highly imperative to detect bilirubin in a fast and label-free manner. Herein, we designed and constructed a random-crossed-woodpile nanostructure from silver nanowires to form a 3-dimensional plasmonic hotspot-rich (3D-PHS) nanostructure and successfully used it to detect direct bilirubin (D-BIL) in human blood in a label-free manner. The 3D-PHS nanochip provides rich spatial hot spots that are simultaneously responsive to SERS and SPEF effects and consequently, successfully used to measure and characterize D-BIL with a detection limit of ∼10 nM, requiring only 10μL of human serum for rapid screening, which is the first time D-BIL has been detected in a clinically relevant range. This demonstrates a simple, label-free, pretreatment-free potential biosensing technology that can be used in health care units, and further, in the efficient detection of point-of-care testing with a portable spectrometer.

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.

Prenatal glucocorticoid administration enhances bilirubin metabolic capacity and increases Ugt1a and Abcc2 gene expression via glucocorticoid receptor and PXR in rat fetal liver

AIM

Jaundice is especially common in premature infant born before 35 weeks. Because the premature infant liver is not fully developed at birth it may be incomplete the bilirubin metabolism. The purpose was to evaluate the metabolism and the excretion of bilirubin in the premature infant rat liver following prenatal glucocorticoid (GC) administration.

METHODS

Dexamethasone (DEX) was administered subcutaneously to pregnant Wistar rats for two consecutive days on gestational days 17 and 19. The fetus were delivered by cesarean section in gestational days 19 and 21. The mRNA levels and protein levels of bilirubin-metabolic enzymes and transporters in the fetal liver tissues were analyzed using RT-PCR immunohistochemistry staining and ELISA, respectively. We evaluated that the effect of bilirubin-metabolic enzymes in the primary fetal rat hepatocytes treated with DEX after pretreated with glucocorticoid receptor (GR, Nr3c1) and Pxr (Nr1i2) siRNA.

RESULTS

Ugt1a1 and Bsep (Abcb11) mRNA levels were significantly increased in the fetuses by prenatal GC administration. The mRNA levels of nuclear transcription factors Nr1i2, Car (Nr1i3), and Rxrα (Nr2b1) were also significantly increased in the fetuses by prenatal GC administration. In addition, DEX increased Nr1i2, Ugt1a1, and Abcc2 (Mrp2) mRNA levels in the primary fetal hepatocytes. The Nr3c1 or Nr1i2 siRNA-mediated knockdown suppressed the increases of Ugt1a1, and Abcc2 mRNA levels induced by DEX, indicating that DEX are mediated by GC receptor and PXR in primary fetal hepatocytes.

CONCLUSIONS

These results suggest that prenatal GC administration increases bilirubin-metabolic ability, in the premature liver, which may prevent jaundice in neonates.

Clinical Assessment of Neuroinflammatory Markers and Antioxidants in Neonates with Hyperbilirubinemia and Their Association with Acute Bilirubin Encephalopathy

Objective: To assess the oxidant and antioxidant status in neonates with and without hyperbilirubinemia and their association with early manifestations of acute bilirubin encephalopathy (ABE), in addition to eliciting the possible oxidative effects of phototherapy. Methods: This prospective observational study was conducted with 104 full-term newborns at Menoufia University Hospitals from January 2020 to January 2021 to help resolve the debate regarding whether bilirubin is an antioxidant. The cases group (Group I) included 52 full-term newborns (37−40 weeks) with hyperbilirubinemia during the neonatal period, while the control group (Group II) included 52 healthy, full-term age and sex-matched newborns who did not have hyperbilirubinemia. The cases group was further subdivided into Group Ia (n = 12), which included newborns who presented with neurological manifestations suggesting early ABE, and Group Ib (n = 40), which included newborns with no signs suggestive of ABE. All newborns were subjected to clinical and neurological examinations, as well as laboratory investigations. Results: Comparing the specific biological markers between the Group 1 subgroups before phototherapy, the mean plasma levels of prostaglandin-Em, prostaglandin E2, and TSB were significantly higher in Subgroup I(a) (all p < 0.05). After phototherapy, Subgroup I(a) patients had significantly higher levels of prostaglandin-Em, DSB, and TSB (p < 0.05). The biological marker levels improved after phototherapy in terms of TAC (0.811 vs. 0.903), MDA (8.18 vs. 5.13), prostaglandin-Em (37.47 vs. 27.23), prostaglandin E2 (81.09 vs. 31.49), DSB (1.21 vs. 0.55), and TSB (16.63 vs. 8.26; p-value < 0.05). Conclusion: Our study showed that an elevated level of serum bilirubin increases oxidative stress and decreases antioxidant capacity. The reduction in bilirubin levels by phototherapy is associated with a decrease in oxidative stress markers (MDA, PGEm, and PGE2) and an upsurge in TAC, highlighting the absence of oxidative stress effects arising from phototherapy. Neonates with neurological manifestations suggesting ABE had higher levels of oxidative stress markers and lower levels of total antioxidant capacity than those without.

Stannsoporfin with phototherapy to treat hyperbilirubinemia in newborn hemolytic disease

OBJECTIVE

To evaluate the efficacy and safety of tin mesoporphyrin (SnMP) in neonates with hyperbilirubinemia (HB) due to hemolysis.

STUDY DESIGN

This multicenter, placebo-controlled phase 2b study (NCT01887327) randomized newborns (35-42 weeks) with hemolysis started on phototherapy (PT) to placebo (Ctrl), SnMP 3.0 mg/kg, or SnMP 4.5 mg/kg given once IM within 30 min of initiation of PT.

RESULTS

In all, 91 patients were randomized (Ctrl: n = 30; 3 mg/kg SnMP: n = 30; 4.5 mg/kg SnMP: n = 31). At 48 h TSB significantly increased in Ctrl by 17.5% (95% CI 5.6-30.7; p = 0.004) and significantly decreased by -13% (95% CI -21.7 to -3.2; p = 0.013) in the 3.0 mg/kg and by -10.5% (95% CI -19.4 to -0.6; p = 0.041) in the 4.5 mg/kg group. Decreases in SnMP groups were significant (p < 0.0001) vs Ctrl.

CONCLUSION

SnMP with PT significantly reduced TSB by 48 h. SnMP may be useful as a treatment for HB in neonates with hemolysis.

Prevalence, risk factors, and audiological characteristics of auditory neuropathy

OBJECTIVE

The objective of this study was to determine the prevalence, risk factors, and audiological characteristics of auditory neuropathy spectrum disorder (ANSD) in the pediatric population.

DESIGN

A retrospective review of medical charts was conducted for children visiting two hospitals in Saudi Arabia.

STUDY SAMPLE

Medical records of 1025 patients with sensorineural hearing loss (SNHL) were reviewed. We analyzed the databases for results of audiological examinations, risk factors, and outcomes of intervention including hearing aid (HA) and cochlear implantation (CI).

RESULTS

Out of 1025 children with SNHL, 101 patients (9.85%) were identified to have ANSD. Audiological characteristics of the ANSD group revealed a severe-to-profound degree of hearing loss, all showed type A tympanogram and absent reflexes, absent auditory brainstem response (ABR) findings with present cochlear microphonic while otoacoustic emissions were absent in 54.5% of patients. The most prevalent risk factors for ANSD in this group were family history of hearing loss, consanguinity, hyperbilirubinemia, and low birth weight. Pure tone and speech detection thresholds improved significantly with CI compared to HA use in this sample of patients with ANSD.

CONCLUSION

This study shows that ANSD is not extremely rare among Saudi children with severe to profound hearing loss, with a prevalence of 9.85%.

Congenital Deafness and Recent Advances Towards Restoring Hearing Loss

Congenital hearing loss is the most common birth defect, estimated to affect 2-3 in every 1000 births. Currently there is no cure for hearing loss. Treatment options are limited to hearing aids for mild and moderate cases, and cochlear implants for severe and profound hearing loss. Here we provide a literature overview of the environmental and genetic causes of congenital hearing loss, common animal models and methods used for hearing research, as well as recent advances towards developing therapies to treat congenital deafness. © 2021 The Authors.

Association between Hyperbilirubinemia and Hearing Screen Failure in the Neonatal Intensive Care Unit in Infants Born Preterm

OBJECTIVE

To characterize the association between hyperbilirubinemia and a failed newborn hearing screen in infants born at 22-32 weeks of gestation.

STUDY DESIGN

We included infants with gestational ages of 22-32 weeks who were discharged from neonatal intensive care units in the US from 2002 to 2017 with available newborn hearing screen results obtained after 34 weeks postmenstrual age. We excluded infants with severe birth asphyxia or craniofacial abnormalities. We identified 95 672 infants from 313 neonatal intensive care units. We used multivariable logistic regression to examine the association between maximum total bilirubin at <21 days postnatal age with failed hearing screen, adjusting for important demographic and clinical risk factors.

RESULTS

The median gestational age and birth weight were 30 weeks (IQR, 28-32 weeks) and 1330 g (IQR, 1010-1630 g), respectively. The median maximum total bilirubin was 8.3 mg/dL (IQR, 6.7-10.0 mg/dL), and 5275 infants (6%) failed their newborn hearing screen. On adjusted analysis, each 1 mg/dL increase in maximum total bilirubin was associated with a small, but significant, increase in odds of a failed hearing screen (OR, 1.03; 95% CI, 1.02-1.04).

CONCLUSIONS

An increased maximum total bilirubin level was independently associated with hearing screen failure. Further prospective studies are needed to understand whether this increased risk of hearing screen failure translates to increased risk of hearing loss.

[Childhood hearing screening: achievements, difficulties, and possible ways to improve]

Hearing impairment is the most common sensory impairment that is seen among adults and children. The frequency of congenital hearing loss is well-known due to implementation of newborn hearing screening. Hearing may change throughout a lifetime due to different factors and, therefore, the number of hearing impaired children increases with age. Introduction of universal newborn hearing screening has enabled earlier detection of hearing loss including unilateral and minimal disorders. Nevertheless, despite significant progress made in this field, there is still a group of hearing impairments that stay undiagnosed timely. Auditory neuropathy spectrum disorders, late-onset hearing loss, low-frequency and minimal hearing impairment are sometimes missed in newborn hearing screening or they manifest later. These types of hearing disorders are covered in detail in this review as well as possible ways of increasing the effectiveness of early diagnosis.

[Role of pyroptosis in bilirubin-induced microglial injury]

OBJECTIVE

To study whether pyroptosis is involved in the bilirubin-induced injury of primary cultured rat cortical microglial cells.

METHODS

Primary cultured rat cortical microglial cells were randomly administered with 30 μmol/L bilirubin (bilirubin group), 30 μmol/L bilirubin following 30 μmol/L VX-765 pretreatment (VX-765+bilirubin group), or an equal volume of dimethyl sulfoxide (control group). Modified MTT assay was used to measure the viability of microglial cells. Western blot was used to measure the expression of the pyroptosis-related proteins Caspase-1 and gasdermin D (GSDMD). Lactate dehydrogenase (LDH)-release assay was used to evaluate the cytotoxicity of microglial cells. EtBr/EthD2 with different molecular weights (394 Da/1 293 Da) was used to measure the size of plasma membrane pores. ELISA was used to measure the level of the inflammatory factor interleukin-1β (IL-1β) in culture supernatant.

RESULTS

After bilirubin stimulation, the viability of microglial cells decreased and LDH release increased, both in a time-dependent manner. Compared with the control group, the bilirubin group had a significantly higher positive rate of small-molecule EtBr passing through the cell membrane (P<0.001), while there was no significant difference in the pass rate of large-molecule EthD2 between groups (P>0.05). The expression of activated Caspase-1 significantly increased at 0.5 hour after bilirubin stimulation (P<0.05), and that of activated GSDMD significantly increased at 6 hours after bilirubin stimulation (P<0.05). The release of IL-1β significantly increased at 6 hours after bilirubin stimulation and reached the peak at 24 hours (P<0.001). Compared with the bilirubin group, the VX-765+bilirubin group had a significant increase in cell viability (P<0.05) and significant reductions in the expression of activated GSDMD, the pass rate of EtBr, and the release of LDH and IL-1β (P<0.05).

CONCLUSIONS

Pyroptosis is involved in bilirubin-induced injury of primary cultured microglial cells.

Hyperbilirubinemia impact on newborn hearing: a literature review

The increase in bilirubin levels in newborns can cause toxic effects on the auditory system, which can lead to hearing loss. This review aimed to verify the impact of hyperbilirubinemia in the hearing of newborns, relating audiological findings to serum levels of bilirubin. A literature review was conducted during October 2017, using the terms "hyperbilirubinemia", "jaundice", "infant", "newborn" and "hearing loss", on databases CAPES journals, MEDLINE and BIREME (SciELO, BBO). 827 studies were identified and 59 were selected for full-text reading, resulting in the selection of seven articles that met the inclusion criteria and were considered relevant to the sample of this study. All the reviewed studies performed brainstem auditory evoked potential as the main test for audiological evaluation. Changes in the audiological findings of neonates with hyperbilirubinemia were observed in all studies. There was no consensus on the serum bilirubin levels that may cause auditory changes; however, the relationship between hearing disorders and blood levels of bilirubin was positive. We identify the need to establish reference values for bilirubin levels considered critical for the occurrence of hearing disorders as well as the audiological follow-up of neonates with hyperbilirubinemia.

Long-term Effects of Indirect Hyperbilirubinemia on Auditory and Neurological Functions in Term Newborns

Objective:

The aim of this study was to investigate the long-term effects of hyperbilirubinemia on neurological and hearing function in otherwise healthy term newborns with neonatal indirect hyperbilirubinemia.

Method:

This study was performed prospectively in 41 term newborns hospitalized for indirect hyperbilirubinemia. Patients with no signs of hemolysis were categorized in 3 groups based on stabil levels as sTB <20 mg/dl, 20-24.9 mg/dl, and =>25 mg/dl. Patients with total bilirubin level =>20 mg/dl and hemolytic disease were classified as the fourth group. The relationship between maximum sTB level, duration of exposure to sTB levels >20 mg/dl and etiology of jaundice with neurological and auditory functions was investigated. Detailed neurological examination, Denver II developmental screening test and hearing tests (otoacoustic emissions, OAE and auditory brainstem responses, ABR) were performed to all patients between 18-24 months of age.

Results:

Neurodevelopmental disorder was found in 5 (12.2%) patients. Hemolytic disease was detected in two of these patients. Hearing loss was found in 4 (9.8%) of the patients. Two of these patients had auditory neuropathy spectrum disorder and the other two had cochlear hearing loss. The sTB levels of all these patients were above 25 mg/dl. No neurological disorder or hearing loss was found in the patients who had stabil of <25 mg/dl. Exposure time to sTB levels above 20 mg/dl was significantly longer in patients with neurological dysfunction and pathologic ABR results (p:0.007, p:0.007; p<0.05).

Conclusion:

This study demonstrates that kernicterus may develop in term newborns with severe hyperbilirubinemia (sTB>25 mg/dl) without any finding of significant hemolysis. Not only the bilirubin level but also the duration of exposure to high bilirubin levels may be effective in the development of bilirubin neurotoxicity. The high rate of hearing loss in our patients emphasizes the importance of screening for infants with severe hyperbilirubinemia using comprehensive auditory evaluation for early diagnosis of possible hearing loss.

Bilirubin Induced Encephalopathy

Hyperbilirubinemia is one of the most common neonatal disorders. Delayed diagnosis and treatment of the pathologic and progressive indirect hyperbilirubinemia lead to neurological deficits, defined as bilirubin induced encephalopathy (BIE) (2). The incidence of this disorder in underdeveloped countries is much more than developed areas. All neonates with the risk factors for increased the blood level of indirect bilirubin are at risk for BIE, especially preterm neonates which are prone to low bilirubin kernicterus . BIE can be transient and acute (with early, intermediate and advanced phases)or be permanent, chronic and lifelong ( with tetrad of symptoms including visual (upward gaze palsy), auditory (sensory neural hearing loss), dental dysplasia abnormalities, and extrapyramidal disturbances (choreoathetosis cerebral palsy).Beside the abnormal neurologic manifestations of the jaundiced neonates ,brain MRI is the best imaging modality for the confirmation of the diagnosis. Although early treatment of extreme hyperbilirubinemia by phototherapy and exchange transfusion can prevent the BIE, unfortunately the chronic bilirubin encephalopathy does not have definitive treatment.

The spectrum of bilirubin neurotoxicity in term and near-term babies with hyperbilirubinemia: Does outcome improve with time?

BACKGROUND

While neonatal jaundice is generally a common benign condition; severe hyperbilirubinemia has a devastating potential for brain injury.

AIM

To detect the impact of severe neonatal hyperbilirubinemia on motor and mental development and its progress over time in the first year of life using the Bayley scales of infant development (BSID) II.

STUDY DESIGN AND PATIENTS

177 term/near-term infants admitted for neonatal hyperbilirubinemia to the NICU of Cairo University Children's Hospital were enrolled. Clinical examination, BIND score and laboratory tests were performed at admission. Neurodevelopmental assessment using BSIDΙΙ was performed at 3 months for 147/177 neonates, and at 6 months and 12 months for 139/177 neonates. Auditory brainstem evoked potential was recorded at 3 months of age and repeated if abnormal.

OUTCOME MEASURES

Psychomotor (PDI) and mental developmental indices (MDI) using BSIDII. Auditory impairment using Auditory Brainstem Response (ABR).

RESULTS

TSB levels ranged from 10 to 63 mg/dL (179.6-1077 μmol/L) with a mean of 25.52 ± 6.5 mg/dL (436 ± 112.9 μmol/L) and BIND scores ranged from 0 to 7. By one year of age, 19/139 patients were affected; 8 had classic kernicterus, 3 had isolated auditory impairment, 1 had severe motor and mild mental delay and 7 had mild motor delay. TSB level and BIND score had positive correlation with auditory impairment and lower scores for PDI (which improved with time) and MDI (which remained stationary). Duration of exposure to hyperbilirubinemia negatively affected neurodevelopmental scores.

CONCLUSION

The impact of severe hyperbilirubinemia is mainly on motor and auditory impairment. Mild mental delay was detected by BSIDII in few patients. Neurodevelopmental outcome improves over time.

Bilirubin-induced neurotoxic and ototoxic effects in rat cochlear and vestibular organotypic cultures

Exposure to high levels of bilirubin in hyperbilirubinemia patients and animal models can result in sensorineural deafness. However, the mechanisms underlying bilirubin-induced damage to the inner ear, including the cochlear and vestibular organs, remain unknown. The present analyses of cochlear and vestibular organotypic cultures obtained from postnatal day 3 rats exposed to bilirubin at varying concentrations (0, 10, 50, 100, or 250 μM) for 24 h revealed that auditory nerve fibers (ANFs) and vestibular nerve endings were destroyed even at low doses (10 and 50 μM). Additionally, as the bilirubin dose increased, spiral ganglion neurons (SGNs) and vestibular ganglion neurons (VGNs) exhibited gradual shrinkage in conjunction with nuclei condensation or fragmentation in a dose-dependent manner. The loss of cochlear and vestibular hair cells (HCs) was only evident in explants treated with the highest concentration of bilirubin (250 μM), and bilirubin-induced major apoptosis most likely occurred via the extrinsic apoptotic pathway. Thus, the present results indicate that inner ear neurons and fibers were more sensitive to, and exhibited more severe damage following, bilirubin-induced neurotoxicity than sensory HCs, which illustrates the underlying causes of auditory neuropathy and vestibulopathy in hyperbilirubinemia patients.

[Epidemiology of hearing loss in children of the first year of life]

The aim of this study was the investigation of the epidemiology of permanent hearing impairment in the children of first year of life in the Russian Federation after the implementation of the newborn universal hearing screening program. The prevalence of hearing loss in children in the first year of life was estimated at 2.5 per 1,000 based on the official statistical data and reports of hearing rehabilitation centres in 2016. A cohort of 405 children born in 2012 was examined at the age from 0 to 4 years of life. Among them 276 children were diagnosed with permanent congenital and prelingual hearing loss. 88% of the cases were bilateral, sensorineural hearing loss confirmed in 84% of the cases. The genetic cause of hearing loss was revealed in 58% of the patients assessed for the presence of GJB2 gene mutations. In preterm infants, the permanent hearing loss was detected in 70% of the cases. The comprehensive audiological assessment before 3 months of life was conducted only in 32% of the children; this finding is not consistent with the international newborn hearing screening recommendations. Only 70% of the cases of congenital and preverbal hearing loss were diagnosed during the first year of life.

Ethnopharmacological Approaches for Therapy of Jaundice: Part I

Jaundice is a very common symptom especially in the developing countries. It is associated with several hepatic diseases which are still major causes of death. There are many different approaches to jaundice treatment and the growing number of ethnomedicinal studies shows the plant pharmacology as very promising direction. Many medicinal plants are used for the treatment of jaundice, however a comprehensive review on this subject has not been published. The use of medicinal plants in drug discovery is highly emphasized (based on their traditional and safe uses in different folk medicine systems from ancient times). Many sophisticated analytical techniques are emerging in the pharmaceutical field to validate and discover new biologically active chemical entities derived from plants. Here, we aim to classify and categorize medicinal plants relevant for the treatment of jaundice according to their origin, geographical location, and usage. Our search included various databases like Pubmed, ScienceDirect, Google Scholar. Keywords and phrases used for these searches included: "jaundice," "hyperbilirubinemia," "serum glutamate," "bilirubin," "Ayurveda." The first part of the review focuses on the variety of medicinal plant used for the treatment of jaundice (a total of 207 medicinal plants). In the second part, possible mechanisms of action of biologically active secondary metabolites of plants from five families for jaundice treatment are discussed.

Ethnopharmacological Approaches for Therapy of Jaundice: Part I

Jaundice is a very common symptom especially in the developing countries. It is associated with several hepatic diseases which are still major causes of death. There are many different approaches to jaundice treatment and the growing number of ethnomedicinal studies shows the plant pharmacology as very promising direction. Many medicinal plants are used for the treatment of jaundice, however a comprehensive review on this subject has not been published. The use of medicinal plants in drug discovery is highly emphasized (based on their traditional and safe uses in different folk medicine systems from ancient times). Many sophisticated analytical techniques are emerging in the pharmaceutical field to validate and discover new biologically active chemical entities derived from plants. Here, we aim to classify and categorize medicinal plants relevant for the treatment of jaundice according to their origin, geographical location, and usage. Our search included various databases like Pubmed, ScienceDirect, Google Scholar. Keywords and phrases used for these searches included: “jaundice,” “hyperbilirubinemia,” “serum glutamate,” “bilirubin,” “Ayurveda.” The first part of the review focuses on the variety of medicinal plant used for the treatment of jaundice (a total of 207 medicinal plants). In the second part, possible mechanisms of action of biologically active secondary metabolites of plants from five families for jaundice treatment are discussed.

Prediction of 3- to 5-Month Outcomes from Signs of Acute Bilirubin Toxicity in Newborn Infants

OBJECTIVE

To evaluate the ability of the bilirubin-induced neurologic dysfunction (BIND) score to predict residual neurologic and auditory disability and to document the relationship of BIND score to total serum bilirubin (TSB) concentration.

STUDY DESIGN

The BIND score (assessing mental status, muscle tone, and cry patterns) was obtained serially at 6- to 8-hour intervals in 220 near-term and full-term infants with severe hyperbilirubinemia. Neurologic and/or auditory outcomes at 3-5 months of age were correlated with the highest calculated BIND score. The BIND score was also correlated with TSB.

RESULTS

Follow-up neurologic and auditory examinations were performed for 145/202 (72%) surviving infants. All infants with severe acute bilirubin encephalopathy (BIND scores 7-9) either died or suffered residual neurologic and auditory impairment. Of 24 cases with moderate encephalopathy (BIND 4-6), 15 (62.5%) resolved following aggressive intervention and were normal at follow-up. Three of 73 infants with mild encephalopathy (BIND scores 1-3) but severe jaundice (TSB ranging 33.5-38 mg/dL; 573-650 µmol/L) had residual neurologic and/or auditory impairment. A BIND score ≥4 had a specificity of 87.3% and a sensitivity of 97.4% for predicting poor neurologic outcomes (receiver operating characteristic analysis). BIND scores trended higher with severe hyperbilirubinemia (r² = 0.54, P < .005), but 5/39 (13%) infants with TSB ≥36.5 mg/dL (624 µmol/L) had BIND scores ≤3, and normal outcomes at 3-5 months.

CONCLUSIONS

The BIND score can be used to evaluate the severity of acute bilirubin encephalopathy and predict residual neurologic and hearing dysfunction.

Bilirubin-Induced Neurological Dysfunction: A Clinico-Radiological-Neurophysiological Correlation in 30 Consecutive Children

The clinical expression of bilirubin-induced neurological dysfunction varies according to severity and location of the disease. Definitions have been proposed to describe different bilirubin-induced neurological dysfunction subtypes. Our objective was to describe the severity and clinico-radiological-neurophysiological correlation in 30 consecutive children with bilirubin-induced neurological dysfunction seen over a period of 5 years. Thirty children exposed to acute neonatal bilirubin encephalopathy were included in the study. The mean peak total serum bilirubin level was 625 μmol/L (range 480-900 μmol/L). Acoustic brainstem responses were abnormal in 73% (n = 22). Pallidal hyperintensity was observed on magnetic resonance imaging in 20 children. Peak total serum bilirubin levels correlated with motor severity (P = .03). Children with severe motor impairment were likely to manifest severe auditory neuropathy (P < .01). We found that in a resource-constrained setting, classical kernicterus was the most common bilirubin-induced neurological dysfunction subtype, and the majority of children had abnormal acoustic brainstem responses and magnetic resonance imaging.

Diagnosis and Management of Congenital Sensorineural Hearing Loss

Hearing loss is the most common sensory disorder in the USA. The diagnosis of congenital hearing loss starts with newborn hearing screening, which is best performed with auditory brainstem evoked responses in order to avoid the risk of missing auditory neuropathy spectrum disorder. A careful history and physical exam can occasionally help reveal the etiology for congenital hearing loss. Imaging studies, either CT temporal bones or MRI of the internal auditory canals without gadolinium, and genetic testing, in particular for connexin 26, connexin 30, and Pendred syndrome, are the most useful diagnostic tests. Management of congenital hearing loss involves early fitting of amplification. Early cochlear implantation, preferably before 2 years of age, should be strongly considered for children with bilateral severe hearing loss.

Bilirubin-Induced Audiologic Injury in Preterm Infants

Although hyperbilirubinemia is extremely common among neonates and is usually mild and transient, it sometimes leads to bilirubin-induced neurologic damage (BIND). The auditory pathway is highly sensitive to the effects of elevated total serum/plasma bilirubin (TB) levels, with damage manifesting clinically as auditory neuropathy spectrum disorder. Compared to full-term neonates, preterm neonates are more susceptible to BIND and suffer adverse effects at lower TB levels with worse long-term outcomes. Furthermore, although standardized guidelines for management of hyperbilirubinemia exist for term and late preterm neonates, similar guidelines for neonates less than 35 weeks gestational age are limited.

Auditory neuropathy--neural and synaptic mechanisms

Sensorineural hearing impairment is the most common form of hearing loss, and encompasses pathologies of the cochlea and the auditory nerve. Hearing impairment caused by abnormal neural encoding of sound stimuli despite preservation of sensory transduction and amplification by outer hair cells is known as 'auditory neuropathy'. This term was originally coined for a specific type of hearing impairment affecting speech comprehension beyond changes in audibility: patients with this condition report that they "can hear but cannot understand". This type of hearing impairment can be caused by damage to the sensory inner hair cells (IHCs), IHC ribbon synapses or spiral ganglion neurons. Human genetic and physiological studies, as well as research on animal models, have recently shown that disrupted IHC ribbon synapse function--resulting from genetic alterations that affect presynaptic glutamate loading of synaptic vesicles, Ca(2+) influx, or synaptic vesicle exocytosis--leads to hearing impairment termed 'auditory synaptopathy'. Moreover, animal studies have demonstrated that sound overexposure causes excitotoxic loss of IHC ribbon synapses. This mechanism probably contributes to hearing disorders caused by noise exposure or age-related hearing loss. This Review provides an update on recently elucidated sensory, synaptic and neural mechanisms of hearing impairment, their corresponding clinical findings, and discusses current rehabilitation strategies as well as future therapies.

Newborn hearing screening programme in Belgium: a consensus recommendation on risk factors

Background

Understanding the risk factors for hearing loss is essential for designing the Belgian newborn hearing screening programme. Accordingly, they needed to be updated in accordance with current scientific knowledge. This study aimed to update the recommendations for the clinical management and follow-up of newborns with neonatal risk factors of hearing loss for the newborn screening programme in Belgium.

Methods

A literature review was performed, and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system assessment method was used to determine the level of evidence quality and strength of the recommendation for each risk factor. The state of scientific knowledge, levels of evidence quality, and graded recommendations were subsequently assessed using a three-round Delphi consensus process (two online questionnaires and one face-to-face meeting).

Results

Congenital infections (i.e., cytomegalovirus, toxoplasmosis, and syphilis), a family history of hearing loss, consanguinity in (grand)parents, malformation syndromes, and foetal alcohol syndrome presented a ‘high’ level of evidence quality as neonatal risk factors for hearing loss. Because of the sensitivity of auditory function to bilirubin toxicity, hyperbilirubinaemia was assessed at a ‘moderate’ level of evidence quality. In contrast, a very low birth weight, low Apgar score, and hospitalisation in the neonatal intensive care unit ranged from ‘very low’ to ‘low’ levels, and ototoxic drugs were evidenced as ‘very low’. Possible explanations for these ‘very low’ and ‘low’ levels include the improved management of these health conditions or treatments, and methodological weaknesses such as confounding effects, which make it difficult to conclude on individual risk factors. In the recommendation statements, the experts emphasised avoiding unidentified neonatal hearing loss and opted to include risk factors for hearing loss even in cases with weak evidence. The panel also highlighted the cumulative effect of risk factors for hearing loss.

Conclusions

We revised the recommendations for the clinical management and follow-up of newborns exhibiting neonatal risk factors for hearing loss on the basis of the aforementioned evidence-based approach and clinical experience from experts. The next step is the implementation of these findings in the Belgian screening programme.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-015-0479-4) contains supplementary material, which is available to authorized users.