Description
Neonatal jaundice, a common condition in newborns, occurs due to elevated bilirubin levels in the blood. Risk factors include prematurity, blood type incompatibility between the mother and baby, and inadequate feeding. While mild cases often resolve on their own, treatment options for more severe jaundice include phototherapy, which helps break down bilirubin, and in extreme cases, exchange transfusion. Early detection and management are crucial to prevent potential complications, such as kernicterus, a type of brain damage associated with very high bilirubin levels.
Résumé
- Neonatal jaundice, a common medical intervention in newborns, is clinically assessed as yellowish skin and sclera discoloration, while hyperbilirubinemia is a lab-defined condition of elevated blood bilirubin levels. All newborns universally experience jaundice to some degree.
- Bilirubin metabolism, the breakdown of heme from hemoglobin, culminates in bilirubin production. Hemoxysinase, a rate-limiting enzyme, converts heme to bilirubin, with variations linked to ethnicity and familial factors. Bilirubin, binding to albumin for safe transport, prevents cellular damage before liver conjugation and excretion.
- Newborns are predisposed to jaundice due to higher RBC mass, ineffective erythropoiesis with shorter RBC lifespan, and immature UDP conjugating enzymes leading to reduced liver conjugation capacity. Enterohepatic circulation, where bilirubin is reabsorbed due to limited gut bacteria activity, further exacerbates jaundice.
- Risk factors for neonatal jaundice vary across populations and include ethnicity (Asian babies), geography (high altitude), season (summer dehydration), family history, genetic conditions (G6PD deficiency), maternal conditions (diabetes, obesity), maternal medications (oxytocin), and blood group discrepancies (Rh incompatibility). Prematurity, low birth weight, and male sex also increase risk.
- Physiological jaundice, a normal occurrence in healthy newborns, appears after 24-48 hours, peaks in a few days, and diminishes within 7-10 days. Asian babies may experience slightly higher bilirubin levels. Exaggerated physiologic jaundice is diagnosed when bilirubin levels reach up to 17 mg/dL.
- Untreated hyperbilirubinemia can lead to bilirubin encephalopathy, caused by free bilirubin crossing the blood-brain barrier and damaging immature neuronal cells. Acute bilirubin encephalopathy can progress to kernicterus, resulting in long-term neurological deficits such as athetosis, dystonia, deafness, gaze palsies, and dental hypoplasia.
- Primary prevention of hyperbilirubinemia involves identifying risk factors for hemolysis, such as Rh incompatibility. Universal screening for jaundice involves predischarge risk assessment, a predischarge bilirubin screening, and promoting breastfeeding.
- Clinical assessment of jaundice involves visual examination using Kramer's rule, estimating bilirubin levels based on cephalocaudal progression of skin staining. However, it depends on observer skill, lighting conditions, and baby's skin color, leading to potential inaccuracies. Transcutaneous bilirubinometers offer a non-invasive alternative, reliably measuring bilirubin levels up to 15 mg/dL.
- Laboratory assessment includes cause-specific tests to identify underlying conditions such as hemolysis, RBC morphology abnormalities, or thyroid dysfunction. Bilirubin to albumin ratio can be measured, with a ratio of >8 in term infants, or >7 in late preterm infants suggesting increased risk of free bilirubin.
- Management includes phototherapy, which uses blue light to isomerize bilirubin for excretion, and, in severe cases, exchange transfusion. IVIG is used in Rh incompatibility to block maternal antibodies, while IV fluids can improve phototherapy efficacy in dehydrated or low birth weight babies. Follow-up is crucial to monitor for rebound hyperbilirubinemia.
- Emerging technologies involve artificial intelligence and machine learning for jaundice assessment using mobile phone cameras, potentially improving accuracy and accessibility of diagnosis.
Exemple de certificat
À propos des intervenants
Dr Saikiran Deshabhotla
Néonatologiste consultant principal, hôpital Fernandez, Hyderabad
Divulgation financière
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