Do all infants with unconjugated hyperbilirubinemia require phototherapy?

From the Guidelines

Not all infants with unconjugated hyperbilirubinemia require phototherapy, as treatment decisions depend on the infant's bilirubin level, age in hours, and risk factors. According to the most recent and highest quality study 1, phototherapy is an essential intervention for severe hyperbilirubinemia, especially in neonates at high risk. The timing of intervention is guided by performing serial measurements of total serum/plasma bilirubin (TSB) concentrations and screening for the presence of intrinsic risk factors for bilirubin neurotoxicity.

Key Considerations for Phototherapy

• Phototherapy is typically initiated when bilirubin levels exceed specific thresholds based on nomograms that consider the infant's age and risk status 1.
• For example, a term infant without risk factors might not need phototherapy until bilirubin levels reach 15-18 mg/dL at 48-72 hours of life, while a preterm or high-risk infant might require treatment at lower levels (10-12 mg/dL) 1.
• Many cases of mild jaundice can be managed with increased feeding frequency to enhance bilirubin excretion, particularly in breastfed infants.
• Close monitoring is essential for all jaundiced infants, with follow-up bilirubin measurements scheduled according to the initial level and trajectory.

Phototherapy Mechanism and Effectiveness

• Phototherapy works by converting unconjugated bilirubin into water-soluble isomers that can be excreted without liver conjugation, preventing the potential neurotoxic effects of high bilirubin levels that could lead to kernicterus 1.
• The effectiveness of phototherapy depends on the efficacy of the device used and the net gradient between an infant’s rates of bilirubin production and elimination 1.
• Phototherapy needs to be delivered in measurable doses (irradiance), which makes it conceptually similar to pharmacotherapy 1.

Clinical Guidelines for Phototherapy

• The American Academy of Pediatrics provides clinical practice guidelines for the management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation, which include the use of phototherapy 1.
• The guidelines recommend intensive phototherapy at thresholds based on gestational age, neurotoxicity risk factors, and age of the infant in hours 1.
• Clinicians should evaluate the underlying cause or causes of hyperbilirubinemia in infants who require phototherapy, and glucose-6-phosphate dehydrogenase enzyme activity should be measured in any infant with jaundice of unknown cause whose TSB rises despite intensive phototherapy 1.

From the Research

Unconjugated Hyperbilirubinemia Treatment

• Not all infants with unconjugated hyperbilirubinemia require phototherapy, as the condition can resolve spontaneously in some cases 2.
• Phototherapy is the mainstay of treatment for neonatal hyperbilirubinemia, and its effectiveness in lowering total serum bilirubin levels has been demonstrated in several studies 2, 3.
• The use of intensive phototherapy has been shown to be effective in preventing neurological complications and achieving a sustained reduction of bilirubin levels, making it a viable alternative to exchange transfusion in some cases 2.
• Other treatment options, such as metalloporhyrins, clofibrate, bile salts, laxatives, and bilirubin oxidase, are being explored as potential pharmacological therapies for unconjugated hyperbilirubinemia, but more research is needed to determine their safety and efficacy 4.
• Albumin administration has been shown to prevent neurological damage and death in a mouse model of severe neonatal hyperbilirubinemia, and may be a potential treatment option in certain cases 5.

Determining the Need for Phototherapy

• Transcutaneous bilirubin (TcB) measurements can be used to identify infants who may require phototherapy, but the predictive performance of TcB varies across different treatment criteria 6.
• The number of infants requiring phototherapy can vary significantly depending on the treatment criteria used, highlighting the need for careful evaluation and consideration of individual patient needs 6.
• TcB may be useful in identifying infants who do not require phototherapy, but may also identify a high proportion of false positives, which can be burdensome in resource-limited settings 6.