Neonatal Indirect Hyperbilirubinemia (>35 weeks) (Kutilda, 1/5/2022)

Many thanks to Dr. Pumi Kutilda who is such a dedicated teacher for our residents and gave an excellent detail-packed, graphic-filled presentation on Neonatal Indirect Hyperbilirubinemia this week. 

A recording of her presentation is available HERE.

Abbreviations used below: Total serum bilirubin (TsB), Transcutaneous bilirubin (TcB), gestational age (GA), Red blood cells (RBC), Risk factors (RF)

• Severe hyperbilirubinemia TsB >20 mg/dl (during first 28 days)
• Critical hyperbilirubinemia TsB>25 mg/dl  (during first 28 days)
• Cholestasis is defined as Direct bilirubin >1 mg/dl (need be checked only ONCE)
• RBC lifespan in newborns is 70-80 days (compared to 120 for adults)
• the lower the GA, the lower the RBC lifespan-- which puts preemies at higher risk
• High levels of free unconjugated bilirubin (not bound to albumin) crosses the blood brain barrier (specifically the globus pallidus) and causes neurological effects (i.e. kernicterus)
• this is why babies w/low albumin (<3) are at higher risk for hyperbilirubinemia 
  

History and Physical Exam are essential in diagnosis and management

• Prematurity 
•  <35 weeks GA, be sure to use the Preemie Bili Tool
•  >35 weeks GA use the regular Bili Tool 
• Polycythemia
• Known Hemolysis
• History of dehydration, suboptimal breastfeeding, poor latch, etc
• Constipation

Work up for Neonatal Hyperbilirubinemia

CBC + Diff, reticulocyte count + blood smear (retic count is critical because determines whether or not there is hemolysis, may need to be done serially), albumin, BMP/CMP, Direct bilirubin (just once to rule out conjugated hyperbilirubinemia), CBG/ABG + lactate (if hypoxic), G6PD (if hemolysis identified), Urine Culture (silent infection), thyroid function tests (if persistent jaundice >2 weeks)

See Pumi's excellent graphic for representation of how the peripheral blood smear can determine diagnosis

Where do we go wrong with diagnosing hyperbilirubinemia?

• missed hemolytic disease (e.g. G6PD deficiency)
• not repeating reticulocyte count

Physical Exam

lethargy, s/sx dehydration, hypertonia, "scared" upward gaze, high pitched cry

Screening and Management

1) Promote breastfeeding 

            Should be based on feeding cues

            No forced or supplemental feeding <24 hours (very minimal intake first 24 hours)

            Amount to feed is based on time after birth (H)

                    12-24 hours: 5-10ml q2-3 hour

                    24-48 hours: 10-30ml q2-3 hours

                    48-72 hours: 15-30ml q2-3 hour

                    72-96 hours: >30ml >8 times/day

2) Risk factor assessment 

    MOST important RF: gestation age <38 weeks, sibling who required phototherapy, visible jaundice first 24 hours, maternal coomb's positive

    LESS important RF: male, non-white (esp SE Asian), exclusive breastfeeding, cephalohematoma or significant bruising

Absence of these risk factors means extremely low risk for severe hyperbilirubinemia

    

3) Hour specific TcB screening: @12 hours, 24 hours (plotted on hour specific nomogram)

4) Assess adequate intake via both weight measurements AND stool patterns

                                #stools + # urine             weight loss %

                                    <24 hours 1+1                     <3%

                                    48 hours 2+2                        <7%

                                    72 hours 3+3                        7%

5) Risk factors for phototherapy: GA + hemolytic disease, suspected sepsis, asphyxia, acidosis, serum albumin <3

Added Pearls

• Both ibuprofen and naproxen increase bilirubin so are not used in newborns (indomethacin is used instead, eg PFO closure)
• To avoid degradation and ensure accurate measurements, blood should be carefully handled,  drawn into clouded red tube, and sent to lab to evaluated right away (<2 hours)
• Of note, TcB using one of two specific machines (JM103, JM105-- one of which we have at SSRRH) correlates VERY well with TsB except when TsB gets very high (>17). 
• We should be considering the TcB results as quite accurate as long as TcB is <13. 
• IF TcB>13, TsB indicated right away
• Home phototherapy (via bili blanket) is an option for medically stable patients (no neurotoxicity risk factors, no hemolysis, feeding well and well appearing). Costs about $200 delivery and $85/day. Patients have to pay up front but are generally reimbursed by their insurance
• There are new guidelines from UCSF (Northern California Neonatal Consortium), not active at SSRRH yet but soon will be. Keep your eye out