BIOCHEMICAL PROFILE OF JAUNDICE

1. DR MUHAMMAD MUSTANSAR FJMC
LAHORE — . BIOCHEMICAL PROFILE OF JAUNDICE
• 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 flexibilityand
become pikilocytes (spherical), increasingly rigidand fragile. Once the cell
become fragile, they easilydestruct during passage through tight
circulationspots, especially in spleen, where the intra-capillaryspace is
about 3 micron as compared to 8 micron ofcell 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
bymacrophages.
• 4. Formation of Bilirubin• Primary site of synthesis:- SPLEEN: The
Graveyard of Red Blood Cells• Secondary site of synthesis:- LIVER &
BONE MARROW
• 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¬ An average person TOTAL BILIRUBIN produces about
4 mg/kg of bilirubin per day. 85% 15% HEMOGLOBIN RBC

2. PRECURSORS¬5. & 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 HemeHemeOxygenase 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, abridging methylenegroup is cleaved
byheme oxygenase toform Linear Biliverdinfrom Cyclic Hememolecule.
Heme Oxygenase OxidationFe 2+ is released fromthe ring in this process.
I III IV II
• 10. Heme Oxygenase I C NADPHIV Fe2+ II O2 O2 III
• 11. IV III II I Biliverdin
• 12. HNADPHBilirubin

3. • 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 toalbumin.
• 16. In cells of the liver, bilirubin undergoes modification to In cells
of the liver, bilirubin undergoes modification toincrease its water solubility
so that it can be excreted more increase its water solubility so that it can be
excreted moreeasily. easily.a.Bilirubin is conjugated to twoa.Bilirubin is
conjugated to twomolecules of glucuronic acid, creatingmolecules of
glucuronic acid, creatingbilirubin diglucuronide.bilirubin diglucuronide.b.
Bilirubin diglucuronide is transportedb. Bilirubin diglucuronide is
transportedout of the hepatocytes into the bileout of the hepatocytes into
the bilecanaliculi 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

4. • 18. Role of Blood Proteins in the Metabolism of Bilirubin 1. Albumin
Dissolved in Blood
• 19. BloodLiver Ligandin Ligandin (-) charge (-) charge Ligandin
Prevents bilirubin from going back to plasma
• 20. In Endoplasmic ReticulumIn the microsomes of the
endoplasmic reticulum,unconjugated bilirubin is converted to water
solublemono- or di- conjugates by sequential covalentcoupling with
glucuronic acid.
• 21. Bilirubin is conjugated ina two step process toform bilirubin
mono- &di- glucuronide
• 22. Conjugation with Glucoronates BILIRUBIN DIGLUCORONIDE
• 23. Heme oxygenase BiliverdinHeme Biliverdin reductase
BilirubinBILIRUBIN PHYSIOLOGY
• 24. Excretion of Bilirubin
• 25. 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.
• 26. • 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

5. • 27. • 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.
• 28. JAUNDICE
• 29. SYMPTOMSo 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!!!
• 30. Clinical SignificanceHyperbilirubinemia & 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.
• 31. • 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
• 32. Different Causes of Jaundice • Excessive Production of
Bilirubin • Reduced Hepatocyte Uptake • Impaired Bilirubin conjugation •
Impaired Bile Flow
• 33. Classification JaundicePre-hepatic Hepatic Post-Hepatic

6. • 34. 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)
• 35. 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
• 36. • 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.
• 37. • 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.
• 38. Ongoing liver damage with liver cell necrosisfollowed by
fibrosis and hepatocyteregeneration results in cirrhosis. Thisproduces a
nodular, firm liver. The nodulesseen here are larger than 3 mm and,
hence,this is an example of "macronodular"
• 39. Obstructive jaundiceDefinition : Is a conditioncharacterized
byYellow discolorationof the skin , sclera &mucous membrane asa result of
an elevatedSr. Bilirubin conc. dueto an obstructive cause.
• 40. Posthepatic(Obstructive) jaundice • Caused by an obstruction
of the biliary tree. • Plasma bilirubin is conjugated, and other biliary

7. 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.
• 41. • • 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.
• 42. Pre-hepatic Hepatic Post hepaticcause Excessive break down
Infective Bile Duct Obstruction Of RBC’s Liver Damage Malaria,HS Gilbert
SyndromeSerum Bilirubin unconjugated Both conj+unconj.
conjugatedUrine bilirubin Absent Bilirubinemia + As in hepatic jaundice
Achloric jaundice Deep yellow urine ++Urine Increases Decreases
Absent(-)urobilinogen Because of increased Because of decreased
stercobilinogen stercobilinogenFecal Markedly increased Reduced
Absentstercobilinogen Dark brown stool Pale coloured stool clay colored
stool20-250mg/dayFecal fat 5-6% normal Increased 40-50% As hepatic
jaundice Bulky,pale greasy foul smelling faecesLiver functions normal
Impaired SGOT/SGPT Normal Alkaline phosphatase++Vonden burg test
Indirect+ biphasic Direct+
• 43. Diagnoses of Jaundice
• 44. 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

8. 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.
• 45. • 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
• 46. CLINICAL FEATURES• Severe unconjugated
hyperbilirubinemia at birthPrior to phototherapy:• Kernicterus• Death in
infancy
• 47. Phototherapy•Phototherapy is usually not neededunless the
bilirubin levels rise veryquickly or go above 16-20 mg/dl inhealthy, full term
babies.• During phototherapy, thetreatment of choice forjaundice, babies
are placedunder blue lights that convert the bilirubin into compoundsthat
can be eliminated fromthe body.
• 48. Phototherpy forinfants
• 49. 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
• 50. Inherited Disorders of Bilirubin Metabolism • Gilbert’s
Syndrome • Crigler-Najjar (Type I) • Crigler-Najjar (Type II) • Lucey-Driscoll
• Dubin-Johnson • Rotor’s Syndrome

9. • 51. 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 syndromesPossibility 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
• 52. 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.
• 53. 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.
• 54. 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).
• 55. 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,

10. 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.
• 56. Rotor’s Syndrome• It is another form of conjugated
hyperbilirubinemia.• It is similar to dubin-johnson syndrome but without
pigmentation in liver.