Liver & GIT
Abnormal excretory function of hepatocytes may be assessed by: (PGI June 07)
|C||Increased Alkaline Phosphatase|
|D||Increased gamma GT|
A. Enzymes that reflect cholestasis:
1. Alkaline phosphatase – the normal value is 30-120 IU/L.
The sources are:
a. Liver, b. Bone c. Placenta, d. Small Intestine
The causes of elevation of ALP are:
a. Age > 60 yr (11/2 times the normal).
b. Adolescents – undergoing rapid bone growth.
c. Pregnancy – In last trimester due to influx of placental ALP.
a. Liver disease –More rise occurs in obstructive jaundice. Q
b. Primary or metastatic tumor of bone.
c. Hodgkin’s disease
d. Paget’s disease
f. Sclerosing cholangitis
NB: Level of ALP is normal in multiple myeloma.
Causes of Reduced ALP levels:-
a. Magnesium deficiency
d. Hemolytic anemia
e. Wilson's Disease
f. Post coronary bypass surgery
g. Estrogen replacement therapy
h. Congenital hypophosphatasia.
i. Blood transfusion causes transient decreases in ALP, due to chelation of cations by citrate.
(Ref. Hari-18th ed., Pg. 1925) (AIIMS Nov 09)
In screening for liver metastasis it has a high predictive value. Q
3. Gamma-glutamyl transpeptidase –
GGT is a potential marker of alcoholism Q.
4. Leucine amino peptidase – This is useful in the diagnosis of biliary obstructive Q, space occupying Q and infiltrative disorder Q of the liver.
B. Tests that measures biosynthetic function of the liver:
Serum proteins – liver produces all the serum proteins Q – albumin, prothrombin, fibrinogen, alpha and beta globulin etc except gamma globulin Q.
A reversal of A: G ratio suggest a chronic liver diseaseQ.
1. Serum albumin – It has a half life of 15-20 Q days, hence will be decreased in chronic liver disease.
2. Serum globulins – They are made up of:
→ Gamma globulin (Immunoglobulin) produced by B lymphocyte Q.
→ Alpha & Beta globulin, produced by hepatocytes Q.
Increase in specific isotypes of gamma globulins are helpful in recognizing certain chronic liver diseases:
1. Raised IgG – autoimmune hepatitis Q
2. Raised IgM – Primary biliary Q cirrhosis
3. Raised IgA – Alcoholic liver disease Q
4. Coagulation factors – The liver synthesize all the coagulation factors except factor VIII Q.
5. The shortest half life is 6 hrs for factor VII and longest 5 days for fibrinogen.
6. For this prothrombin time is used which measures factor II, V, VII and X.
7. Prolongation of PT> 5 sec above control and not corrected by Parenteral vit K administration is a poor prognostic sign in liver diseases: Q ( extra edge – stored blood is deficient in Factor-V and Factor -VIII)