Y2 W18 S1 - Jaundice

Front 1

Jaundice: Where do most of the bilirubin come from?

Back 1

85% of daily production (0.2-0.3gm) from senescent RBC breakdown by macrophages in spleen, liver, and bone marrow.

The rest (15%) comes from:
turnover of hepatic heme,
hemoproteins (P450s etc.), or
premature destruction in bone marrow.

Front 2

Jaundice:

Differentiate between unconjugated and conjugated bilirubin.

Back 2

Unconjugated bilirubin
- Exists as tightly-bound albumin complexes
- Cannot be excreted in urine
(even at high levels).
- A small amount of albumin-free unconjugated bilirubin exists in plasma (toxic to tissues)

Conjugated bilirubin (bilirubin glucoronides)
- Water-soluble,
- Nontoxic
- Loosely bound to albumin.
- Can be freely excreted in urine

Front 3

MECHANISM: Jaundice

Back 3

Jaudice is evident when plasma levels rise above 2.0-2.5mg/dL
(normal is 0.3 - 1.2mg/dL).

Jaudice occurs in
1) Excessive hepatic production of bilirubin,
2) reduced hepatocyte uptake,
3) impaired conjugation,
= High unconjugated bilirubin

4) decreased hepatocellular excretion,
5) impaired bile flow.
= High conjugated bilirubin