10

Question 1

It is a transient, physiologic jaundice,
because

Answer 1

the activity of hepatic bilirubin
UDP-glucuronyl transferase (UGT) is low at
birth. UGT reaches adult levels in about 4
weeks.

Question 2

Elevated unconjugated bilirubin, in excess of
the binding capacity of albumin (20–25
mg/dl), can cause?

Answer 2

can penetrate blood-brain barrier and
diffuse into the basal ganglia.
• If left untreated → toxic encephalopathy, or
kernicterus → can causes mental retardation.

Question 3

Neonatal; Physiologic Jaundice:

They are treated with

Answer 3

blue fluorescent light (phototherapy) that converts bilirubin to
more water-soluble photo-isomers → can be
excreted into bile without conjugation.

Question 4

Crigler-Najjar Syndrome Types I & II:
• Both types are due to defects in

Answer 4

UDP- glucuronyl transferase activity.

Question 5

the severe form of Crigler-Najjar Syndrome?

Answer 5

Type I is the severe form → serum bilirubin over 20 mg/dL → brain damage that reflects the complete absence of the enzyme activity.
Phototherapy ↓ plasma bilirubin levels somewhat, but phenobarbital has no beneficial effect.
• The disease is often fatal within the first 15 months of life.

In type II, some of the enzyme activity is retained→ more benign course.
Serum bilirubin tends not to exceed 20 mg/dL and the patients respond to treatment with large doses of phenobarbital.

Question 6

Gilbert’s Syndrome:

It is due to

Answer 6

• Benign unconjugated hyperbilirubinemia with normal liver
chemistries.
• It is due to low activity of bilirubin UDP-glucuronyl transferase

Question 7

Common Liver Chemistry Tests
Synthetic Functions of the Liver:

Answer 7

o Albumin: 3.4 - 4.7mg/dL, 40% of albumin is present in plasma & 60% is present in extracellular spaces ,, essential for maintenance of osmotic blood pressure Important for transport of many substances

oTotal Plasma Proteins: 7.0 - 7.5 g/dL The major plasma proteins: albumin, globulins & fibrinogen.

oProthrombin Time: One of coagulation factors that is synthesized in liver in the presence of vitamin K. Prothrombin is transformed into thrombin by clotting factor X. Thrombin then transforms fibrinogen → fibrin. Fibrin in combination with platelets → forms a clot.

The most common tests used as prognostic factors are:
PT, albumin & bilirubin

Question 8

Cause of Prolonged Prothrombin Time:

Answer 8

§ Liver disease. § Vitamin K deficiency: malabsorption, malnutrition, antibiotics. § Congenital disease. § Warfarin. §
Massive transfusion.

Question 9

Causes of Low Serum Albumin Levels:

Answer 9

§ The most common reason is chronic liver failure caused by liver cirrhosis.
§ ↓ Serum albumin levels are NOT seen in acute liver failure. It takes several weeks of impaired albumin production before serum albumin level ↓.
§ ↓ Serum albumin due to some other conditions than liver disease:
- Sever malnutrition.
- Some kidney diseases:→ extensive albumin loss in urine.
- Severe burns: → damage capillaries & blood vessels → huge loss of serum
proteins.

Question 10

Importance of Liver Enzymes in Clinical Diagnosis:

Answer 10

Liver transaminases; ALT & AST; are NOT true liver function but they are biomarkers of “liver injury”.

Other tests to assess liver functions include: GGT, ALP & its
hepatic isoenzyme and 5’-nucleotidase.

Question 11

ALT catalyzes the following reaction:

Answer 11

Alanine + α-Ketoglutarate → Pyruvate + Glutamate

Question 12

AST catalyzes the following reaction:

Answer 12

Aspartate + α-Ketoglutarate → Oxaloacetate + Glutamate
§ AST is found in many tissues.

§ Not very specific for liver disease. § Often follows ALT to a degree.

Question 13

AST , ALT in

Answer 13

AST : Cytosol (20%) and in mitochondria ,,, liver, cardiac muscle, skeletal muscle, kidneys, brain, pancreas, lungs, leucocytes, and RBC.

ALT: Cytosol more specific to the liver.

Question 14

ALT AST: Reference range

Answer 14

AST: Reference range (0 up to 35 IU/L). ALT: Reference range (0 up to 45 IU/L).

Question 15

Cholestasis

Answer 15

o ALP,
o GGT,
o 5’-nucleotidase, (Bilirubin & bile acids)

Question 16

Hepatocellular Damage:

Answer 16

o AST (SGOT): decrease specificity
o ALT (SGPT) : increase specificity
o LDH.

Question 17

Alkaline Phosphatase:

Found in nearly all tissues as

Answer 17

liver, “mainly in biliary tract”, bone,
intestine, placenta, kidney…
Liver ALP isoenzyme ↑ with obstruction (stones), or infiltrative
diseases (tumors).

Question 18

γ -Glutamyltransferase (γ- Glutamyltranspeptidase) GGT is abundant in

GGT reference range: Increased in:

Answer 18

liver, kidney, pancreas, intestine, and prostate,
spleen, heart, brain but not in bone.

GGT is very sensitive but not specific test, raised in any liver
disease either hepatocellular or cholestatic.

GGT reference range: 0 to 30 IU/L. § Increased in:
oAlmost all types of liver diseases.
oAlcoholics.
oSome drugs.
oRenal failure, DM, hyperthyroidism, pancreatic disease, …

Question 19

5’ Nucleotidase (5’NTD):
u It is also specific for

Answer 19

cholestasis or damage to the biliary system.

Question 20

Common Markers of Hepatic Neoplasms:

Answer 20

1. Alpha fetoprotein (AFP): Normally is less than 25ug/L.
   § Levels > 500 ug/L is diagnostic of primary hepatocellular carcinoma (HHC).
2. Carcinoembryonic antigen (CEA): N: 0-5 ug/L. § Increased CEA levels indicates liver metastatic carcinoma or other GIT carcinomas. The most frequent cancer which causes an increased CEA is cancer of
   the colon and rectum.

Benign conditions which can elevate CEA include smoking, infections,
inflammatory bowel disease, pancreatitis, cirrhosis of the liver and some benign tumors in the same organs i

Question 21

Normal Values Of Liver Chemistry Tests:
§ ALP:
…………IU/L.
§ GGT: ……
§ PT: ………….. sec
§ Albumin:

Answer 21

Normal Values Of Liver Chemistry Tests:
§ ALT: 0-45 IU/L § AST: 0-35 IU/L. § ALP: 30-120 IU/L. § GGT: 0-30 IU/L. § Bilirubin: -Total bilirubin: 0.3 – 1.2 mg/ dL.
-Direct bilirubin: less than 0.8 mg/dL.
§ PT: 10.9-12.5 sec. § Albumin: 40-60 g/L