NEONATAL JAUNDICE
DEFINITION:
A disorder caused by an excess of unconjugated or conjugated
bilirubin in the newborn period.
EPIDEMIOLOGY:
- incidence: ?
- age of onset:
- risk factors:
- see differential diagnosis
DIFFERENTIAL DIAGNOSIS FOR UNCONJUGATED HYPERBILIRUBINEMIA:
DIFFERENTIAL DIAGNOSIS OF CONJUGATED HYPERBILIRUBINEMIA:
PATHOPHYSIOLOGY:
- end product of heme degradation
- majority derived from RBC's
- 8-10 mg/kg/day produced
- 1g Hb = 35 mg bilirubin
- two types:
- unconjugated (indirect) - prehepatic, enterohepatic
- conjugated (direct) - hepatic
2. Physiological Jaundice:
3. Non-Physiological Jaundice:
- see differential diagnosis
CLINICAL FEATURES:
- appears on Day 2
- peaks on Days 2-5
- disappears after Day 7 (term infants)
- disappears after Day 14 (premature infants)
- of term babies:
- 60% are jaundiced within the first week
- 95% have a bilirubin < 260 umol/L
- visible jaundice occurs at levels > 85 umol/L
2. Non-Physiologic Jaundice
- within 24 hours
- total bilirubin > 225 umol/L
- direct bilirubin > 35 umol/L or > 30-40% of total
- rate of rise > 85 umol/L in a 24 hour period
- persists > 7 days (term) or > 14 days (preterm)
3. Approach
INVESTIGATIONS:
- bilirubin (total and direct)
- blood groups and Rh (mother and infant)
- CBC (Hct, Hb, Platelets)
- Coombs test
- peripheral blood smear/morphology
- reticulocyte count
2. Second Line
- septic work-up
- cultures (blood, CSF, urine), chest x-ray
- screen for hypothyroidism
- screen for inborn errors of metabolism
- urine for organic and amino acids
- plasma for amino acids
- alkaline denaturation of Hb test of emesis
- - PT, PTT, haemoglobin electrophoresis
MANAGEMENT:
- interrupt breast-feeding
- stimulate enterohepatic circulation
2. Phototherapy
- based on birth weight and age of patient
- white or blue lights, single or double bank
- principle: photoisomerization
3. Exchange Transfusion
- direct removal of bilirubin
4. Medications
- phenobarbital trial to induce glucuronyl transferase
activity
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