Jaundice biochemical profile

1. BIOCHEMICAL PROFILE OF
JAUNDICE
DR MUHAMMAD MUSTANSAR

2. Introduction
• Bilirubin is the orange-yellow pigment derived from
senescent red blood cells.
• It is a toxic waste product in the body.
• It is extracted and biotransformed mainly in the liver, and
excreted in bile and urine.
• It is a bile pigment
• Elevations in serum and urine bilirubin levels are normally
associated with Jaundice.

3. Erythrocytes become “old” as they lose their flexibility
and become pikilocytes (spherical), increasingly rigid
and fragile. Once the cell become fragile, they easily
destruct during passage through tight circulation
spots, especially in spleen, where the intra-capillary
space is about 3 micron as compared to 8 micron of
cell size
RBCs useful life span is 100 to 120 days,After
which they become trapped and fragment in smaller
circulatory channels, particularly in those of the spleen.
For this reason, the spleen is sometimes called the “red
blood cell graveyard.”
Dying erythrocytes are engulfed and destroyed by
macrophages.

4. Formation of Bilirubin
• Primary site of synthesis:-
SPLEEN: The Graveyard
of Red Blood Cells
• Secondary site of synthesis:-
LIVER & BONE MARROW

5.  An average person TOTAL BILIRUBIN
produces about 4
mg/kg of bilirubin
per day. 85% 15%
HEMOGLOBIN RBC PRECURSORS
 The daily bilirubin FROM SENESCENT DESTROYED IN THE
RBC’S DESTROYED IN BONE MARROW
production from all RETICULOENDOTHELIAL
sources in man CELLS OF
averages from 250 LIVER, SPLEEN & CATABOLISM OF
to 300 mg. BONE MARROW HEME-CONTAINING
PROTEINS (MYOGLOBIN,
CYTOCHROMES &
PEROXIDASES)

6. Extravascular Pathway for RBC Destruction
(Liver, Bone marrow,
& Spleen)
Phagocytosis & Lysis
Hemoglobin
Globin Heme Bilirubin
Amino acids Fe2+
Amino acid pool Recycled Excreted

7. Pathophysiology
RBCs
Breakdown
Hemoglobin Produces
& Breakdown
Heme
Heme
Oxygenase
Biliverdin
Biliverdin
Reductase
Bilirubin

8. • The globin is recycled or converted into amino acids, which
in turn are recycled or catabolized as required.
• Heme is oxidized, with the heme porphyrin ring being
opened by the endoplasmic reticulum enzyme, heme
oxygenase.
• The oxidation occurs on a specific carbon producing
equimolar amounts of the biliverdin, iron , and carbon
monoxide (CO). This is the only reaction in the body that is
known to produce CO.
• Most of the CO is excreted through the lungs, with the
result that the CO content of expired air is a direct measure
of the activity of heme oxygenase in an individual.

9. In the first reaction, a
bridging methylene
group is cleaved by
heme oxygenase to
form Linear Biliverdin
from Cyclic Heme
molecule. Heme Oxygenase
Oxidation
Fe 2+ is released from
the ring in this process.
I III IV II

10. Heme Oxygenase
I
C NADPH
IV Fe2+ II
O2 O2
III

11. IV III II I
Biliverdin

12. H
NADPH
Bilirubin

13. I III IV II
• In the next reaction, a second
bridging methylene (between
rings III and IV) is reduced by
biliverdin reductase,
producing bilirubin.
Reduction Biliverdin Reductase
I III IV II

14. • biliverdin causing a change in the color of the molecule
from blue-green (biliverdin) to yellow-red (bilirubin).
• The latter catabolic changes in the structure of tetrapyrroles
are responsible for the progressive changes in color of a
hematoma, or bruise, in which the damaged tissue changes
its color from an initial dark blue to a red-yellow and finally
to a yellow color before all the pigment is transported out of
the affected tissue.
• Peripherally arising bilirubin is transported to the liver in
association with albumin, where the remaining catabolic
reactions take place.

15. Bilirubin is not very water-soluble, so most of it is carried to the liver bound to
albumin.

16. In cells of the liver, bilirubin undergoes modification to
In cells of the liver, bilirubin undergoes modification to
increase its water solubility so that it can be excreted more
increase its water solubility so that it can be excreted more
easily.
easily.
a.Bilirubin is conjugated to two
a.Bilirubin is conjugated to two
molecules of glucuronic acid, creating
molecules of glucuronic acid, creating
bilirubin diglucuronide.
bilirubin diglucuronide.
b. Bilirubin diglucuronide is transported
b. Bilirubin diglucuronide is transported
out of the hepatocytes into the bile
out of the hepatocytes into the bile
canaliculi and is thus excreted in bile.
canaliculi and is thus excreted in bile.

17. In Blood Unconjugated bilirubin
• The bilirubin synthesized in – Lipid soluble
spleen, liver & bone marrow – : limits excretion
is unconjugated bilirubin. – 1 gm albumin binds 8.5
mg bilirubin
• It is hydrophobic in nature so – Fatty acids & drugs can
it is transported to the liver displace bilirubin
as a complex with the – Indirect positive reaction
plasma protein, albumin. in van den Bergh test

18. Role of Blood Proteins in the
Metabolism of Bilirubin
1. Albumin
Dissolved in Blood

19. Blood
Liver
Ligandin Ligandin
(-) charge (-) charge
Ligandin Prevents bilirubin from
going back to plasma

20. In Endoplasmic Reticulum
In the microsomes of the endoplasmic reticulum,
unconjugated bilirubin is converted to water soluble
mono- or di- conjugates by sequential covalent
coupling with glucuronic acid.

21. Bilirubin is conjugated in
a two step process to
form bilirubin mono- &
di- glucuronide

22. Conjugation with Glucoronates
BILIRUBIN DIGLUCORONIDE

23. Heme oxygenase Biliverdin
Heme
Biliverdin reductase
Bilirubin
BILIRUBIN PHYSIOLOGY

27. Excretion of Bilirubin

28. In the Intestine
• In the small intestine, conjugated bilirubins are poorly
reabsorbed, but are partly hydrolyzed back to unconjugated
bilirubin by catalytic action of bacterial ß-glucuronidases.
• In the distal ileum and colon, anaerobic flora mediate further
catabolism of bile pigments:
a) hydrolysis of conjugated bilirubin to unconjugated bilirubin by
bacterial β-glucuronidases;
b) multistep hydrogenation (reduction) of unconjugated bilirubin to
form colorless urobilinogens; and
c) oxidation of unconjugated bilirubin to brown colored
mesobilifuscins.

29. • Urobilinogens is a collective
term for a group of 3
tetrapyrroles;
– Stercobilinogen (6H)
– Mesobilinogen (8H)&,
– Urobilinogen (12H)
• Upto 20 % of urobilinogen
produced daily is reabsorbed
from the intestine & enters the
entero-hepatic circulation.
Urobilinogen Structure

30. • Most of the reabsorbed urobilinogen is taken up by the liver
& is re-excreted in the bile.
• A small fraction (2 % - 5 %) enters the general circulation &
appears in the urine.
• In the lower intestinal tract, the 3 urobilinogens
spontaneously oxidize to produce the corresponding bile
pigments;
– Stercobilin
– Mesobilin &
– Urobilin;
which are orange-brown in color and are the major
pigments of stool.

33. JAUNDICE

34. SYMPTOMS
o Yellowing of the skin, scleras (white of the eye), and
mucous membranes (jaundice)
o Detectable when total plasma bilirubin levels exceed
2mg/100mL
AHHH!!! I have symptoms
of hyperbilirubinemia!!!

35. Clinical Significance
Hyperbilirubinemia & Types of Jaundice
• Hyperbilirubinemia : Increased plasma concentrations
of bilirubin (> 3 mg/dl) occurs when there is an
imbalance between its production and excretion.
• Recognized clinically as jaundice.
• Also known as icterus, a yellow discoloration of the
skin, sclerae and mucous membrane.

36. • Jaundice becomes clinically evident when the serum
bilirubin level exceeds 2.5mg/dL.
• Several types of Jaundice:
– Hemolytic
– Hepatocellular
– Obstructive
• Symptoms:
– Yellow discoloration of the skin, sclerae and mucous
membranes
– Itching (pruritus) due to deposits of bile salts on the skin
– Stool becomes light in color
– Urine becomes deep orange and foamy

37. Different Causes of Jaundice
• Excessive Production of Bilirubin
• Reduced Hepatocyte Uptake
• Impaired Bilirubin conjugation
• Impaired Bile Flow

38. Classification
Jaundice
Pre-hepatic Hepatic Post-Hepatic

41. Prehepatic (hemolytic) jaundice
• Results from excess production
of bilirubin (beyond the livers
ability to conjugate it) following
hemolysis
• Excess RBC lysis is commonly
the result of autoimmune
disease; hemolytic disease of the
newborn (Rh- or ABO-
incompatibility); structurally
abnormal RBCs (Sickle cell
disease); or breakdown of
extravasated blood
• High plasma concentrations of
unconjugated bilirubin (normal
concentration ~0.5 mg/dL)

42. Hepatic jaundice
• Impaired uptake, conjugation,
or secretion of bilirubin
• Reflects a generalized liver
(hepatocyte) dysfunction
• In this case,
hyperbilirubinemia is usually
accompanied by other
abnormalities in biochemical
markers of liver function

43. • Hemolytic jaundice arises as a
consequence of excessive destruction
of RBCs.
• – This overloads the capacity of the RE
system to metabolize heme.
• – Failure to conjugate bilirubin to
glucuronic acid causes accumulation of
bilirubin in the unconjugated form in the
blood.

44. • Hepatocellular jaundice arises from
liver disease, either inherited or
acquired.
• – Liver dysfunction impairs conjugation of
bilirubin.
• – Consequently, unconjugated bilirubin
spills over into the blood.
• –In addition, urobilinogen is elevated in
the urine.

45. Ongoing liver damage with liver cell necrosis
followed by fibrosis and hepatocyte
regeneration results in cirrhosis. This
produces a nodular, firm liver. The nodules
seen here are larger than 3 mm and, hence,
this is an example of "macronodular"

46. Obstructive jaundice
Definition :
Is a condition
characterized by
Yellow discoloration
of the skin , sclera &
mucous membrane as
a result of an elevated
Sr. Bilirubin conc. due
to an obstructive cause.

47. Posthepatic(Obstructive) jaundice
• Caused by an obstruction of
the biliary tree.
• Plasma bilirubin is conjugated,
and other biliary metabolites,
such as bile acids accumulate
in the plasma.
• Characterized by pale colored
stools (absence of fecal
bilirubin or urobilin), and dark
urine (increased conjugated
bilirubin).
• In a complete obstruction,
urobilin is absent from the
urine.

48. • • Obstructive jaundice, as the name implies,
is caused by blockage of the bile duct by a
gallstone or a
• tumor (usually of the head of the pancreas).
• – This prevents passage of bile into the intestine
and consequently conjugated bilirubin builds up
in the blood.
• – Patients with this condition suffer severe
abdominal pain associated with the
obstruction (if due togallstone) and their feces
are gray in color due to lack of stercobilin.

49. Pre-hepatic Hepatic Post hepatic
cause Excessive break down Infective Bile Duct Obstruction
Of RBC’s Liver Damage
Malaria,HS
Gilbert Syndrome
Serum Bilirubin unconjugated Both conj+unconj. conjugated
Urine bilirubin Absent Bilirubinemia + As in hepatic jaundice
Achloric jaundice Deep yellow urine ++
Urine Increases Decreases Absent(-)
urobilinogen Because of increased Because of decreased
stercobilinogen stercobilinogen
Fecal Markedly increased Reduced Absent
stercobilinogen Dark brown stool Pale coloured stool clay colored stool
20-250mg/day
Fecal fat 5-6% normal Increased 40-50% As hepatic jaundice
Bulky,pale greasy foul
smelling faeces
Liver functions normal Impaired SGOT/SGPT Normal
Alkaline phosphatase++
Vonden burg test Indirect+ biphasic Direct+

50. Diagnoses of Jaundice

51. Neonatal Jaundice
• Common, particularly in premature infants.
• Transient (resolves in the first 10 days).
• Due to immaturity of the enzymes involved in bilirubin
conjugation.
• High levels of unconjugated bilirubin are toxic to the
newborn – due to its hydrophobicity it can cross the
blood-brain barrier and cause a type of mental
retardation known as kernicterus
• If bilirubin levels are judged to be too high, then
phototherapy with UV light is used to convert it to a
water soluble, non-toxic form.

52. • If necessary, exchange blood transfusion is used to remove
excess bilirubin
• Phenobarbital is oftentimes administered to Mom prior to
an induced labor of a premature infant – crosses the
placenta and induces the synthesis of UDP glucuronyl
transferase
• Jaundice within the first 24 hrs of life or which takes longer
then 10 days to resolve is usually pathological and needs
to be further investigated

53. CLINICAL FEATURES
• Severe unconjugated hyperbilirubinemia at birth
Prior to phototherapy:
• Kernicterus
• Death in infancy

54. Phototherapy
•Phototherapy is usually not needed
unless the bilirubin levels rise very
quickly or go above 16-20 mg/dl in
healthy, full term babies.
• During phototherapy, the
treatment of choice for
jaundice, babies are placed
under blue lights that convert
the bilirubin into compounds
that can be eliminated from
the body.

55. Phototherpy for
infants

56. Bilirubin Toxicity - Kernicterus
• Kernicterus or brain encephalopathy refers to the yellow
staining of the deep nuclei (i.e., the kernel) of the brain
namely, the basal ganglia.
• It is a form of permanent brain damage caused by
excessive jaundice.
• The concentration of bilirubin in serum is so high that it can
move out of the blood into brain tissue by crossing the fetal
blood-brain barrier.
• This condition develops in newborns with prolonged
jaundice due to:
– Polycythemia
– Rh incompatibility between mother & fetus

57. Inherited Disorders of Bilirubin
Metabolism
• Gilbert’s Syndrome
• Crigler-Najjar (Type I)
• Crigler-Najjar (Type II)
• Lucey-Driscoll
• Dubin-Johnson
• Rotor’s Syndrome

58. Algorithm for differentiating the familial causes of
Hyperbilirubinemia
Isolated increased serum bilirubin
Ruling out of hemolysis, subsequent fractionation of the bilirubin
Conjugated Unconjugated
Possibility of following syndromes
Possibility of the
based on the bilirubin concentration:
following syndromes:
• Gilbert’s - <3 mg/dl
• Dublin-Johnson
• Crigler-Najjar (Type I) - >25 mg/dl
• Rotor
• Crigler-Najjar (Type II) - 5 to 20 mg/dl
• Lucey-Driscoll - Transiently ~ 5 mg/dl

59. Crigler-Najjar Syndrome (Type I)
• Crigler-Najjar Syndrome (Type I) is a rare genetic disorder
caused by complete absence of UDP-
glucuronyltransferase and manifested by very high levels of
unconjugated bilirubin.
• It is inherited as an autosomal recessive trait.
• Most patients die of severe brain damage caused by
kernicterus within the first year of life.
• Early liver transplantation is the only effective therapy.

60. Crigler-Najjar Syndrome (Type II)
• This is a rare autosomal dominant disorder.
• It is characterized by partial deficiency of UDP-
glucuronyltransferase.
• Unconjugated bilirubin is usually 5 – 20 mg/dl.
• Unlike Crigler-Najjar Type I, Type II responds
dramatically to Phenobarbital & a normal life can be
expected.

61. Gilbert’s Syndrome
• Gilbert’s syndrome is also called as familial non-hemolytic
non-obstructive jaundice.
• mild unconjugated Hyperbilirubinemia.
• It affects 3% – 5% of the population. It is often misdiagnosed
as chronic Hepatitis.
• The concentration of Bilirubin in serum fluctuates between 1.5
& 3 mg/dl.
• In this condition the activity of hepatic glucuronyltransferase is
low as a result of mutation in the bilirubin-UDP-
glucuronyltransferase gene(UGT1A1).

62. Dubin-Johnson Syndrome
• It is a benign, autosomal recessive
condition characterized by jaundice
with predominantly elevated
conjugated bilirubin and a minor
elevation of unconjugated bilirubin.
• Excretion of various conjugated
anions and bilirubin into bile is
impaired, reflecting the underlying
defect in canalicular excretion.
• The Liver has a characteristic
greenish black appearance and liver
biopsy reveals a dark brown melanin-
like pigment in hepatocytes and
kupffer cells.

63. Rotor’s Syndrome
• It is another form of conjugated hyperbilirubinemia.
• It is similar to dubin-johnson syndrome but without
pigmentation in liver.