Relationship between exposure to icterogenic agents, glucose-6-phosphate dehydrogenase deficiency and neonatal jaundice in Nigeria

Neonatal Jaundice: Knowledge and Practices of Healthcare Providers and Trainees in Southwest Nigeria

Severe neonatal jaundice (SNNJ) is a leading cause of neonatal morbidity and mortality in low- and middle-income countries (LMICs). Risk mitigation and management modalities for SNNJ have led to marked reduction in complications in high-income countries but not in LMICs likely in part due to knowledge gaps among healthcare providers. This study, a cross-sectional study conducted in Ogbomosho, Nigeria, aimed to identify SNNJ knowledge and practices among Nigerian healthcare providers/trainees. Healthcare providers/trainees completed a structured questionnaire. Healthcare providers/trainees included are nurse midwives (33.4%), nurses (18.6%), nursing students (15.2%), traditional birth attendants (TBAs) (12.7%), physicians (10.2%), and medical students (9.9%). Most physicians were aware of the common causes of SNNJ; however, knowledge deficits in other groups were notable. Despite most providers endorsing that glucose-6-phosphate dehydrogenase deficiency can cause SNNJ (91% of physicians, 60% of nurses, 71% of midwives, 81% of medical students, 43% of nursing students, 7% of TBAs), very few providers recognized that it is common, ranging from 3% in nurses up to a high of 47% among medical students. Gaps in provider knowledge regarding preventative measures and sequela were also noted. These data identified significant knowledge gaps regarding the etiology of SNNJ among healthcare providers/trainees, which can lead to missed opportunities in effective prevention and treatment. These deficits must be addressed if we are to eliminate tragic and preventable complications from SNNJ in Nigeria and other LMICs.

Risk factors for neonatal hyperbilirubinemia: a systematic review and meta-analysis

BACKGROUND

Hyperbilirubinemia is the most common cause of neonatal hospitalization and, although it generally has a good prognosis, a significant percentage of neonatal patients maintain a high bilirubin level, which can lead to severe complications, including lifelong disability such as growth retardation, encephalopathy, autism and hearing impairment. The study of risk factors for neonatal hyperbilirubinemia has been controversial. Therefore, we evaluated the risk factors of neonatal hyperbilirubinemia using a meta-analysis.

METHODS

Relevant English and Chinese studies that discussed risk factors for neonatal hyperbilirubinemia were retrieved from the PubMed, EMBASE, Medline, Central, China National Knowledge Infrastructure (CNKI), Wanfang and China Science Digital Library (CSDL). The literature took newborns as the research object, set up a control group, and observed the relationship between exposure factors and neonatal hyperbilirubinemia. The combined effect size was expressed by odds ratio (OR) and 95% confidence interval (CI). The Chi-square test was used to test heterogeneity of the studies, and if it existed, subgroup analyses were used to explore the source of heterogeneity, and the random-effects model was selected for the combined analysis. The fixed-effects model was chosen for the combined analysis if there was no heterogeneity. Publication bias was assessed using Egger's test and funnel plot.

RESULTS

Risk factors for neonatal hyperbilirubinemia were exclusive breastfeeding (BF: OR =1.74, 95% CI: 1.42, 2.12, Z=5.43, P<0.00001); glucose-6-phosphate dehydrogenase deficiency (G6PD: OR =1.62, 95% CI: 1.44, 1.81, Z=8.39, P<0.00001); maternal-fetal ABO blood group incompatibility (OR =1.64, 95% CI: 1.42, 1.89, Z=6.75, P<0.00001); and preterm birth (PTB: OR =1.31, 95% CI: 1.17, 1.47, Z=4.60, P<0.00001); there was no heterogeneity or publication bias among the studies (BF: χ²=5.34, P=0.25, I²=25%; G6PD: χ²=4.40, P=0.49, I²=0%; ABO: χ²=1.91, P=0.75, I²=0%; PTB: χ²=0.81, P=0.67, I²=0%).

CONCLUSIONS

Exclusive breastfeeding, G6PD deficiency, ABO incompatibility and premature birth were confirmed as risk factors for neonatal hyperbilirubinemia. Pregnant women with risk factors should be monitored more closely and clinical intervention should be given in a timely manner.

Maternal Instruction About Jaundice and the Incidence of Acute Bilirubin Encephalopathy in Nigeria

OBJECTIVE

To evaluate whether teaching mothers about neonatal jaundice will decrease the incidence of acute bilirubin encephalopathy among infants admitted for jaundice.

STUDY DESIGN

This was a multicenter, before-after and cross-sectional study. Baseline incidences of encephalopathy were obtained at 4 collaborating medical centers between January 2014 and May 2015 (Phase 1). Structured jaundice instruction was then offered (May to November 2015; Phase 2) in antenatal clinics and postpartum. Descriptive statistics and logistic regression models compared 3 groups: 843 Phase 1 controls, 338 Phase 2 infants whose mothers received both antenatal and postnatal instruction (group A), and 215 Phase 2 infants whose mothers received no instruction (group B) either because the program was not offered to them or by choice.

RESULTS

Acute bilirubin encephalopathy occurred in 147 of 843 (17%) Phase 1 and 85 of 659 (13%) Phase 2 admissions, which included 63 of 215 (29%) group B and 5 of 338 (1.5%) group A infants. OR for having acute bilirubin encephalopathy, comparing group A and group B infants adjusted for confounding risk factors, was 0.12 (95% CI 0.03-0.60). Delayed care-seeking (defined as an admission total bilirubin ≥18 mg/dL at age ≥48 hours) was the strongest single predictor of acute bilirubin encephalopathy (OR 11.4; 6.6-19.5). Instruction decreased delay from 49% to 17%. Other major risk factors were home births (OR 2.67; 1.69-4.22) and hemolytic disease (hematocrit ≤35% plus bilirubin ≥20 mg/dL) (OR 3.03; 1.77-5.18). The greater rate of acute bilirubin encephalopathy with home vs hospital birth disappeared if mothers received jaundice instruction.

CONCLUSIONS

Providing information about jaundice to mothers was associated with a reduction in the incidence of bilirubin encephalopathy per hospital admission.

Patterns of acute bilirubin encephalopathy in Nigeria: a multicenter pre-intervention study

BACKGROUND

Acute bilirubin encephalopathy (ABE) is an important cause of neonatal morbidity in Nigeria, accounting for 5-14% of neonatal deaths. Most newborns with severe ABE have irreversible damage before receiving treatment emphasizing the need for timely pre-admission monitoring and referral. There is limited evidence that educational interventions targeting mothers and health care providers will reduce delayed care.

OBJECTIVE

To provide baseline data on the incidence of ABE and associated pre-admission risk factors in five centers of Nigeria in order to evaluate the effect of subsequent educational interventions on outcome.

STUDY DESIGN

The incidence of ABE among newborns treated for hyperbilirubinemia was documented prospectively. Bivariate analysis and multivariate logistic regression were used to evaluate risk factors for acute bilirubin encephalopathy and reasons for regional differences in its occurrence.

RESULTS

Of 1040 infants, 159 treated for hyperbilirubinemia (15.3%) had mild to severe bilirubin encephalopathy (including 35 deaths), but the incidence ranged from 7 to 22% between centers. Logistic regression identified four common predictors: total serum bilirubin (odds ratio 1.007 per mg/dl rise), out-of-hospital births (OR 2.6), non-alloimmune hemolytic anemia (OR 2.8), and delayed care seeking (OR 4.3).

CONCLUSION

The high occurrence of bilirubin encephalopathy in Nigeria is due in large part to a delay in seeking care. A planned intervention strategy will target conditions leading to severe hyperbilirubinemia and delay.

Markers of oxidative stress in umbilical cord blood from G6PD deficient African newborns

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked disorder that affects as many as 400 million people worldwide, making it the most common enzymatic defect. Subjects with G6PD deficiency are more likely to develop neonatal hyperbilirubinemia potentially leading to kernicterus and are at increased risk for acute hemolytic anemia when exposed to pro-oxidant compounds such as anti-malarial drugs. We collected umbilical cord blood from 300 males born in Uganda to assess for novel markers of systemic oxidative stress. We determined that 10.7% of the samples collected were G6PD A- deficient (G202A/A376G) and when these were compared with unaffected controls, there was significantly higher 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentration, elevated ferritin, increased leukocyte count and higher small molecule antioxidant capacity. These data suggest increased baseline oxidative stress and an elevated antioxidant response in umbilical cord blood of patients with G6PD deficiency.

A modified Bilirubin-induced neurologic dysfunction (BIND-M) algorithm is useful in evaluating severity of jaundice in a resource-limited setting

Background

Severe neonatal jaundice with associated acute bilirubin encephalopathy occurs frequently in low- and middle-income countries, where advanced diagnostic technology is in short supply. In an effort to facilitate the physical diagnosis of acute bilirubin encephalopathy, we pilot-tested a modified bilirubin induced neurologic dysfunction scoring algorithm in a group of pediatric trainees (residents) and their mentors (consultants) in a resource-constrained setting.

Methods

Jaundiced Nigerian infants were examined by consultant and resident pediatricians. The modified bilirubin induced neurologic dysfunction score assigned by residents was compared with the clinical diagnosis of acute bilirubin encephalopathy by expert consultants. Demographic information was obtained. Known risk factors were also evaluated among infants with and without acute bilirubin encephalopathy in addition to exploratory analyses. Data were analyzed by Statistical Analysis System; statistical significance was set at p < 0.05.

Results

Three hundred and thirty three paired modified bilirubin induced neurologic dysfunction scores (333) were analyzed and showed excellent agreement (weighted Kappa coefficient 0.7969) between residents and consultants. A modified bilirubin induced neurologic dysfunction score greater than or equal to 3 was highly predictive of a clinical diagnosis of acute bilirubin encephalopathy, with sensitivity of 90.7%, specificity of 97.7%, positive predictive value of 88.9%, and negative predictive value of 98.2%. Exposure to mentholated products was strongly associated with increased risk of acute bilirubin encephalopathy among those with known glucose-6-phosphate dehydrogenase deficiency (odds ratio = 73.94; 95% confidence interval = 5.425-infinity) as well as among those whose G6PD phenotype was unknown (odds ratio = 25.88; 95% confidence interval = 2.845-235.4).

Conclusions

The modified bilirubin induced neurologic dysfunction score for neonatal jaundice can be assigned reliably by both residents and experienced pediatricians in resource-limited settings as reflected in the algorithm’s sensitivity and specificity. It may be useful for predicting the development and severity of acute bilirubin encephalopathy in neonates.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-015-0355-2) contains supplementary material, which is available to authorized users.

Early neonatal bilirubin, hematocrit, and glucose-6-phosphate dehydrogenase status

OBJECTIVE

To document the patterns of bilirubin and hematocrit values among glucose-6-phosphate dehydrogenase (G6PD)-deficient and G6PD-normal Nigerian neonates in the first week of life, in the absence of exposure to known icterogenic agents.

METHODS

The G6PD status of consecutive term and near-term neonates was determined, and their bilirubin levels and hematocrits were monitored during the first week of life. Infants were stratified into G6PD deficient, intermediate, and normal on the basis of the modified Beutler's fluorescent spot test. Means of total serum bilirubin (TSB) and hematocrits of the 3 groups of infants were compared.

RESULTS

The 644 neonates studied comprised 353 (54.8%) boys and 291 (45.2%) girls and 540 (83.9%) term and 104 (16.1%) near-term infants. They consisted of 129 (20.0%) G6PD-deficient, 69 (10.7%) G6PD-intermediate, and 446 (69.3%) G6PD-normal neonates. The G6PD-deficient and G6PD-intermediate infants had higher mean TSB than their G6PD-normal counterparts at birth and throughout the first week of life (P < .001). Mean peak TSB levels were 14.1 (9.48), 10.2 (3.8), and 6.9 (3.3) mg/dL for G6PD-deficient, G6PD-intermediate, and G6PD-normal neonates, respectively. Peak TSB was attained on approximately day 4 in all 3 groups, and trends in TSB were similar. Mean hematocrits at birth were similar in the 3 G6PD groups. However, G6PD-deficient and -intermediate infants had higher declines in hematocrit, bilirubin levels, and need for phototherapy than G6PD-normal infants (P < .001).

CONCLUSIONS

The G6PD-deficient and G6PD-intermediate neonates had a higher risk of neonatal hyperbilirubinemia and would therefore need greater monitoring in the first week of life, even without exposure to known icterogenic agents.

Predictors of acute bilirubin encephalopathy among Nigerian term babies with moderate-to-severe hyperbilirubinaemia

OBJECTIVE

To determine predictors of acute bilirubin encephalopathy (ABE) among term infants presenting with moderate-to-severe hyperbilirubinaemia.

METHODS

Babies with total serum bilirubin >15 mg/dl at the point of admission were studied in a Nigerian tertiary health facility using bivariate and multivariate analysis.

RESULTS

Out of 152 babies, 75 (49.3%) had ABE: 73 had ABE at presentation while two developed ABE after admission. Bivariate analysis showed that body weight <2.5 kg, outside delivery, low maternal education, low socio-economic status, severe anaemia, glucose-6-phosphate dehydrogenase deficiency and metabolic acidosis were significantly associated with ABE. Multivariate analysis also showed that only outside delivery, weight <2.5 kg, presence of severe anaemia and acidosis were the predictors of ABE in this cohort of term babies.

CONCLUSION

The identified predictors of ABE are modifiable and can be used to draw up screening tools for term babies at risk of ABE especially in the developing world.

(TA)n UDP-glucuronosyltransferase 1A1 promoter polymorphism in Nigerian neonates

Nigerian neonates have a high incidence of bilirubin encephalopathy. Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is prevalent in this population. (TA)7 promoter polymorphism in the gene encoding the bilirubin conjugating enzyme UDP-glucuronosyltransferase 1A1 (UGT1A1) potentiates hyperbilirubinemia in G-6-PD deficient neonates. We studied (TA)n allele frequency to determine, at least in part, its contribution to the frequency and severity of hyperbilirubinemia. DNA was extracted from umbilical cord blood of sequentially born Nigerian neonates and the (TA)n UGT1A1 promoter sequence determined. The (TA)n allele distribution was compared with reported adults of varying African ancestry and Sephardic Jewish neonates. Among 88 Nigerian neonates, (TA)6 and (TA)7 alleles were almost equally distributed (0.46 and 0.43, respectively). Some individuals with (TA)5 and (TA)8 sequences were encountered. Allele distribution was similar to that of the African ancestry population but differed from the Sephardic Jewish newborns, in whom the (TA)6/(TA)7 distribution was 0.65/0.35. Whereas 45% of Nigerian alleles and 50% of African ancestry alleles, respectively, included a (TA)7 or (TA)8 sequence, only 35% of Jewish alleles were (TA)7 (p < 0.001), and no (TA)8 alleles were encountered. The high frequency of (TA)n promoter polymorphism, coupled with G-6-PD deficiency, may contribute to the pathogenesis of extreme neonatal hyperbilirubinemia in Nigeria.

Transcutaneous bilirubin measurements and serum total bilirubin levels in indigenous African infants

OBJECTIVE

The objective of this study was to determine whether transcutaneous bilirubin (TcB) measurements correlate with serum total bilirubin (STB) levels in indigenous, darkly pigmented African newborns with varying degrees of skin pigmentation, some of which had developed kernicterus.

METHODS

Jaundiced infants who were < or =2 weeks of age and admitted to Baptist Medical Center-Eku (Eku; n = 29) and Jos University Teaching Hospital (Jos; n = 98) in Nigeria were studied. TcB measurements using the BiliChek were made simultaneously with blood sampling for STB measurements by spectrophotometry before phototherapy.

RESULTS

Using linear regression analysis, we found that measurements of TcB correlated well with those of STB with r values of.90 and.88 for Eku and Jos, respectively. Mean bias and imprecision of TcB measurements as compared with STB measurements for the total population was 0.5 +/- 7.6 mg/dL using the method of Bland and Altman. At STB > or 12 mg/dL, correlation (r =.84) and bias and imprecision (-1.2 +/- 8.6 mg/dL) of measurements were only slightly poorer. Furthermore, when infants were grouped by degree of skin pigmentation, correlations of TcB and STB measurements remained strong.

CONCLUSIONS

From these results, we can conclude that TcB measurements are a useful and reliable index for estimating STB levels in pigmented neonates, including those with hyperbilirubinemia and kernicterus. In the absence of reliable STB measurements, the relatively simple and noninvasive TcB measurements can be an important adjunct in directing phototherapy and exchange transfusions, thereby preventing bilirubin-induced morbidity and mortality in low-technology clinical environments.

Delayed development of sensorineural hearing loss after neonatal hyperbilirubinemia: a case report with brain magnetic resonance imaging

Sensorineural hearing loss has long been known to be a clinical consequence of kernicterus. Brainstem auditory evoked potentials (BAEPs) that occur in hyperbilirubinemic infants, can be reversed in the neonatal period by exchange transfusion. The case was reported in an infant with neonatal hyperbilirubinemia from hemolysis due to glucose-6-phosphate dehydrogenase (G6PD) deficiency and napthalene exposure. BAEPs showed that the baby had normal hearing at 30 decibels at 13 days of age, after exchange transfusions, but had developed profound bilateral sensorineural hearing loss by 7 months of age. The brain magnetic resonance imaging (MRI) findings at 7 months are also presented.

Glucose-6-phosphate dehydrogenase deficiency and carboxyhemoglobin concentrations associated with bilirubin-related morbidity and death in Nigerian infants

Our objective was to determine whether glucose-6-phosphate dehydrogenase (G6PD) deficiency and elevated carboxyhemoglobin (COHb) levels correlated with bilirubin-related morbidity and mortality rates. For this purpose, we studied 55 clinically jaundiced infants admitted to a rural mission hospital in southern Nigeria. Total serum bilirubin levels (range, 80 to 1016 mumol/L (4.7 to 59.4 mg/dl)) correlated with the percentage COHb concentrations (COHb = 0.45 + 0.08 Total serum bilirubin; r = 0.72). Infants were divided into two groups of equal size around the median COHb concentration (COHb range, 0.43% to 5.93% (median = 1.40%), with ambient carbon monoxide of 0.65 +/- 0.03 microL/L). The COHb levels > or = 1.40% were associated with the need for exchange transfusion (15/28, or 54%, vs 5/27, or 19%; p < 0.01) and with an increased incidence of clinical findings compatible with kernicterus (9/28, or 32%, vs 0/27, or 0%; p < 0.01). Mortality rate was 29% (8/29) among infants with higher COHb levels, and 7% (2/28) in those with lower levels (p = 0.08). Thirty-one percent (14/45) of the clinically jaundiced infants tested had G6PD deficiency. Thirty-six percent of the infants with G6PD deficiency died with presumed kernicterus, compared with only 3% (1/31) of the infants with a normal G6PD screening test result (p < 0.01). These data suggest that G6PD deficiency and increased bilirubin production, as indexed by COHb, are associated with jaundice-related morbidity and death in Nigerian infants.