Bile pigments like bilirubin and biliverdin are produced from the breakdown of hemoglobin. Bilirubin is transported to the liver bound to albumin and conjugated with glucuronic acid before being excreted in bile. Elevated levels of bilirubin in blood causes jaundice. Jaundice can be prehepatic from excessive hemolysis, hepatic from liver toxicity, or posthepatic from biliary obstruction. Diagnosis involves liver function tests to differentiate the type based on conjugated and unconjugated bilirubin levels, urine and stool color, and other markers.

2. Presented By:
Md. Sohrab Ali Mollah
Reg. no. 13-05-3052
Course Title: Clinical Pathology and Necropsy
Course Code: PBL 501

3. Pigment
 Bile pigments are endogenous(formed
inside the body), coloured compounds –
breakdown products of the blood pigment
haemoglobin – that are excreted in bile
 The two most important bile pigments are-
 Bilirubin, which is orange or yellow, and
 It’s oxidized form Biliverdin, which is green.

4. Formation of BILIRUBIN
Globin
(Protein)
Heme
(pigment)
Iron+Porphyrins
Open Chained Porphyrin
Biliverdin (Greenish Yellow)
Bilirubin

5. Formation of UROBILINOGEN
 Bound to albumin, bilirubin is then transported
from the mononuclear phagocytic cells to the
liver via the circulation.
 In the hepatocyte, the pigment is cleaved from
albumin, conjugated with glucuronic acid and
excreted in the bile as bilirubin-glucuronide by
the help of enzyme uridine diphosphoglucose
glucuronyl transferase.
 The conjugated bilirubin in the intestine is
reduced by bacteria to urobilinogen
(mesobilirubinogen and stercobilinogen).

6. Fate of BILIRUBIN

7. CLINICAL OCCURRENCE
 Normal Serum Bilirubin: 0.3-1.0 mg/dL
(SI Units: 5.1-17 mmol/L).
 Increased Bilirubin: Hyperbilirubinemia
 Unconjugated Hyperbilirubinemia
 Conjugated Hyperbilirubinemia
 Decreased Bilirubin: Hypobilirubinemia

8. Hyperbilirubinemia
(Jaundice)
 It is an important disorder clinically and
postmortem in which the levels of bilirubin
reach such a high concentration in the blood
that all tissues of the body have yellow
tinge.

9. Hyperbilirubinemia
(Jaundice)
General Signs and symptoms
 The main symptom of jaundice is a yellow
discoloration of the white part of the eyes and of the
skin.
 The conjunctiva of the eye are one of the first tissues
to change color as bilirubin levels rise in jaundice.
This is sometimes referred to as scleral icterus.
However, the sclera themselves are not "icteric"
(stained with bile pigment) but rather the
conjunctival membranes that overlie them.

10. Figure: Jaundice in a Foal Figure: Jaundice in a Sheep
Figure: Jaundice in a DogFigure: Jaundiced-cat

11. Hyperbilirubinemia
(Jaundice)
 Depending on the causative mechanism,
Jaundice (Hyperbilirubinemia) is divided
into 3 types:
i. Hemolytic Jaundice (Prehepatic)
ii. Toxic icterus (hepatic) and
iii.Obstructive icterus (posthepatic)

12. Hyperbilirubinemia
(Jaundice)
 Hemolytic Jaundice (Prehepatic)
Hemolytic jaundice results from excessive
hemolysis of erythrocytes, ordinarily in the
circulating blood

13. Hyperbilirubinemia
(Jaundice)
 Toxic Jaundice (Hepatic)
Toxic jaundice is caused by toxic
substances acting on cells of the liver and
producing hydropic changes, fatty
changes, and necrosis and subsequent
release of conjugated and unconjugated
bilirubin into the bloodstream

14. Hyperbilirubinemia
(Jaundice)
 Obstructive Jaundice (Post-hepatic)
Occurs subsequent to obstruction to
the normal flow of bile anywhere in the
biliary system. This results in the
accumulation of conjugated bilirubin in
the bloodstream and in the urine

15. Hypobilirubinemia
 Lower than normal bilirubin levels are
usually not a concern

16. DIAGNOSIS OF ICTERUS
 The hyperbilirubinemia subsequently causes
increased levels of bilirubin in the extracellular
fluid. Concentration of bilirubin in blood plasmosis
normally below 1.2mg/dL (<25µmol/L). A
concentration higher than 2.5mg/dL (>50µmol/dL)
leads to Jaundice

17. DIAGNOSIS OF ICTERUS
 In mild cases the clinical discoloration may
be equivocal; therefore, laboratory tests
are often required to establish a definitive
diagnosis of jaundice. No single test can
differentiate between various
classifications of Jaundice. A combination
of liver function tests is essential to arrive
at a diagnosis

18. Table of Diagnostic Tests
Function test
Pre-hepatic
Jaundice
Hepatic
Jaundice
Post-
hepatic
Jaundice
Total Bilirubin Normal/ Increased Increased
Conjugated Bilirubin Normal Increased
Unconjugated Bilirubin Normal/ Increased Increased Normal
Urobilinogen Normal/ Increased Decreased
Decreased/
Negative
Urine color Normal
Dark
(Urobilinogen+
Conjugated
Bilirubin)
Dark
(Conjugated
Bilirubin)
Stool color Normal Normal/Pale Pale
Alkaline Phosphatase levels
(ALP)
Normal Increased
Alanine Transferase (ALT) and
Aspartate Tranferase (AST)
levels
Normal Increased
Conjugated Bilirubin in Urine Not present Present
Splenomegaly Present Present Absent

19. TEST FOR BILE PIGMENTS
 For diagnosis of bile ointments in case of
mild case, laboratory tests are required.
Such as-
i. Icterus Index
ii. Direct Bilirubin Determination Test
iii.Van den Bergh reaction
iv.Fouchet’s test
v. Ehrlich’s test