A 2-day-old girl is being evaluated in the newborn nursery. The patient was born at 38 weeks gestation to a 28-year-old primigravida via spontaneous vaginal delivery. The pregnancy was uneventful. Maternal blood type is B, Rh-D positive, and the patient's blood type is O, Rh-D positive. Apgar scores were 8 and 9 at 1 and 5 minutes, respectively. The patient is breastfeeding exclusively and has had 3 wet diapers in the last day. She passed meconium yesterday. The mother noticed mild yellowing of the skin after the last feed. Vital signs are normal. The patient is currently asleep. The anterior fontanelle is open, soft, and flat. There is a firm fluid collection in the left parietal scalp, localized within suture lines. The tympanic membranes are normal bilaterally. The oropharynx is clear and moist. Cardiopulmonary examination is unremarkable. The abdomen is soft with normal bowel sounds. The liver is palpable 2 cm below the costal margin. Skin examination shows jaundice, and there is mild scleral icterus. Which of the following is this patient's greatest risk factor for developing severe hyperbilirubinemia?
Neonatal indirect hyperbilirubinemia | |
Cause | Examples |
↑ Bilirubin |
|
↓ Bilirubin |
|
↑ Enterohepatic |
|
G6PD = glucose-6-phophatase dehydrogenase; RBC = red blood cell. | |
Nearly all newborns develop varying degrees of jaundice with indirect hyperbilirubinemia due to physiologically increased bilirubin production, decreased bilirubin clearance, and increased enterohepatic circulation. Risk factors for severe hyperbilirubinemia include the following:
In this case, the patient has localized scalp swelling that is contained within the suture lines, findings consistent with a cephalohematoma. A cephalohematoma results from birth trauma and typically self-resolves within weeks. However, as the red blood cells within the closed space begin to break down in the first few days of life, unconjugated bilirubin is resorbed and can lead to severe hyperbilirubinemia.
Exclusive breastfeeding is also a potential risk factor for hyperbilirubinemia but typically relates to inadequate milk supply (ie, lactation failure jaundice), leading to weight loss, dehydration, and increased enterohepatic circulation. This patient's 3 wet diapers on day 2 of life are normal and suggest sufficient hydration and milk supply.
(Choices A and D) Jaundice that develops at age >24 hours, as in this case, is often physiologic and is not a risk factor for severe disease. In contrast, the onset of jaundice at age <24 hours is always pathologic and often due to congenital infection or hemolysis (eg, ABO incompatibility). Moreover, ABO incompatibility typically affects newborns with blood type A or B, not type O, who are born to mothers with blood type O due to transplacental transfer of anti-A or anti-B antibodies.
(Choice B) Neonatal hepatomegaly (liver edge >3 cm below costal margin) raises concern for a congenital infection or cholestatic condition, both of which increase the risk of hyperbilirubinemia. This patient has a normal abdominal examination for her age.
(Choice C) In contrast to a term infant like this patient, preterm infants (gestational age <37 weeks) are at increased risk for hyperbilirubinemia; pathogenesis relates to the relative immaturity of the liver (which results in decreased bilirubin conjugation) as well as decreased enteral feeds (which increase enterohepatic circulation).
Educational objective:
Although all newborns have physiologic indirect hyperbilirubinemia, risk factors for severe hyperbilirubinemia include ABO incompatibility, cephalohematoma, prematurity, and jaundice at age <24 hours. Cephalohematoma can lead to jaundice due to the release of unconjugated bilirubin from excessive red blood cell breakdown.