RESUMEN
Extreme levels of bilirubin in newborn is a major cause of lifelong neurodevelopmental impairment, which places a financial burden on healthcare resources and caregivers. To determine the incidence, aetiology and short-term outcomes of extreme hyperbilirubinaemia in term infants born in a resource-limited setting. This is a retrospective observational study looking at term neonates with a birth weight ≥2500 g, born in the Western health subdistrict of Cape Town, South Africa, between 1 January 2019 and 31 December 2020, who were exposed to a serum bilirubin level of ≥430 µmol/L in the first week of life and received care in the public health system. Extreme hyperbilirubinaemia occurred in 59 term infants. The incidence was 74 cases per 100 000 (<0.01%) live births equating to 1 case in every 1345 live births. The cause of hyperbilirubinaemia was identified in 51 of the cases (86%), the most common being ABO incompatibility (31/51, 61%), followed by glucose-6-phosphate dehydrogenase deficiency (11/51, 22%). Twelve infants (20 %) underwent an exchange transfusion. Six infants were encephalopathic. Forty-seven infants (80%) were readmitted after initial post-natal discharge, with a mean age of readmission of 113 h old (SD 31 h). The incidence of extreme hyperbilirubinaemia in the Western health subdistrict of Cape Town is higher than in high-income settings. Further work should focus on training of healthcare workers and education of caregivers, for the early detection of significant hyperbilirubinaemia to prevent neurological complications caused by bilirubin toxicity.
Asunto(s)
Bilirrubina , Humanos , Recién Nacido , Sudáfrica/epidemiología , Estudios Retrospectivos , Incidencia , Femenino , Masculino , Bilirrubina/sangre , Hiperbilirrubinemia Neonatal/epidemiología , Hiperbilirrubinemia Neonatal/etiología , Hiperbilirrubinemia Neonatal/terapia , Deficiencia de Glucosafosfato Deshidrogenasa/epidemiología , Deficiencia de Glucosafosfato Deshidrogenasa/complicacionesRESUMEN
OBJECTIVE: To determine the relationship between R563Q, a mutation of the renal epithelial sodium channel, and hypertension. METHODS: Hypertensive patients with low renin and aldosterone, hypokalemia or resistant hypertension were selected for DNA analysis. Genomic DNA encoding the C-terminal domain of the epithelial sodium channel beta subunit from hypertensives and controls was amplified by polymerase chain reaction and screened for the R563Q mutation by digestion with Sfc1 restriction enzyme, or sequenced. RESULTS: A previously undescribed mutation, R563Q, of the beta epithelial sodium channel was found in 10 of 139 black hypertensives, but was not present in any of 103 black normotensives, a significant (P = 0.0058) difference in frequency. The frequency of the mutation in the subgroup of black low-renin, low-aldosterone hypertensives (four of 14) was significantly (P = 0.0001) greater than in normotensives, and was also greater (P = 0.041) than in normal-high renin hypertensives, suggesting that R563Q is an activating mutation of the epithelial sodium channel. R563Q was also found in seven out of 250 mixed ancestry hypertensives, and was significantly (P = 0.017) associated with low-renin, low-aldosterone hypertension in this population group. The mutation was found in one of 100 mixed ancestry normotensives but not in any of 136 white hypertensives. Of the 18 R563Q patients, 11 had severe hypertension, leading to renal failure in two cases, while only two had hypokalaemia. CONCLUSIONS: R563Q, a new variant of the beta epithelial sodium channel, is associated with low-renin, low-aldosterone hypertension, in South African black and mixed-ancestry patients. Only a minority of individuals with the R563Q allelle fully express the Liddle's syndrome phenotype.