JAUNDICE


See also under "Neonatal Hyperbilirubinemia", Primary Biliary Cirrhosis

I. Bilirubin pathway:

II. Assays for bilirubin:

  1. "Direct": Serum + H2SO4---> color change
  2. "Total": Serum + H2SO4 + CH3OH or Urea-->color change
  3. "Indirect" bili is calculated from total & direct; direct tends to be overestimated & inderect underestimated; nl people have no conj. bili in blood, but dir. test spuriously shows it as 15-20% of total; so if dir. bili is <20% of TB, no real conj. bili in blood!
  4. Delta-Bilirubin = Bili. covalently bound to albumin; occurs in chronic jaundice where albumin synth'd in setting of hyperbilirubinemia. Persists about 2wk after hyperbili resolved (lifetime of albumin). So when source of hyperbili (e.g., stone) is removed, total bilirubin decreases but plateaus at elevated level. If suspect, try urine bili--will be neg., since delta-bili not filtered @ glomerulus
  5. HIDA scan (only useful for evaluating patency of cystic duct); no GB filling = cholecystitis (stone, septic inflamm., or pancreatic Ca)

III. PATTERNS OF ABNORMAL SERUM BILIRUBIN

Condition Total bili Direct bili
Normal <1.0 <0.2
Gilbert's d. <4.0 <0.8
Criegler-Najar I 5 <1.0
Criegler-Najar II ? ?
Hemolytic Jaundice <5.0 <1.0
Common bile duct obstruction 20-40 <20-40
Combined disease 100 <100
  1. Gilbert's Dis: Sl. decrease in glucuronyl transferase; accentuated by stress. Also decreased RBC survival time, nonspecific complaints, e.g. abd. pain. Inherited; can also be acquired in hepatitis
  2. Criegler-Najar: Type I = total, Type II = partial, absence of glucuronyl transferase; pts die in infancy in type I
  3. Combined disease = liver + kidneys; conj. bili is filtered @ glomerulus