Biliary Diseases Flashcards
what are the liver function tests?
ALT, AST, Alkaline Phosphatase, GGT, LDH, Bilirubin
what is ALT? found where? released when? normal range?
type of LFT
found primarily in hepatocytes
released when cells are hurt or destroyed
normal is b/w 7-55 U/L
when does ALT increase?
whenever the hepatocytes are injured
do the LFTs test the function of the liver?
NO!!! they are just enzymes that are created in the liver
what is AST? found where?
type of LFT
Found in liver, heart, muscle, intestine, pancreas
is the AST specific for liver disease?
no!!! when it goes up, doesn’t always mean the liver or hepatocytes are damaged - could be something else
what does the AST follow?
the ALT - when ALT increases, so does AST
when is AST elevated 2 or 3x (vs ALT) giving an AST/ALT ratio >3?
Elevated 2 or 3x (vs ALT) in alcoholics
AST/ALT ratio >3 = alcohol underlying cause
AST normal range
8-48 U/L
what is alkaline phosphatase? found where?
type of LFT
found in liver (esp biliary tract), bones, intestines, & placenta
when does the liver alkaline phosphatase rise? GGT?
with obstruction or infiltrative diseases (i.e. gallstone or tumors)
GGT is considered more specific to liver than AP (helps you determine if AP is elevated d/t biliary disease)
what is the normal range of alkaline phosphatase?
45-114 U/L
what is GGT?
enzyme found in many organs - highest concentration in the liver
a type of lLFT
when is GGT elevated?
elevated in blood in most diseases that cause damage to liver or bile ducts
the first enzyme to be elevated in damage to the liver
if alk phos is elevated and unsure if d/t bone or liver, what do you check?
the GGT
if normal GGT then likely d/t bone disease
if GGT elevated in setting of Alk phos, d/t liver disease
(elevated in 75% of ETOH abuse)
what is LDH? elevated in? found where?
type of LFT
enzyme found in blood and liver
elevated in tissue damage, so if liver damaged, may be elevated
what is bilirubin?
yellow pigment formed in the liver by the breakdown of Hgb and excreted in bile
when is bilirubin elevated?
- jaundice
- liver disease and blockage of the bile ducts
- any process which increases the breakdown of RBCs (hemolytic anemia)
- anything that affect the production or elimination of bilirubin
what are the 2 forms of bilirubin?
unconjugated bilirubin “indirect”
conjugated bilirubin “direct”
what is unconjugated bilirubin “indirect”?
heme that is released from Hgb is converted to unconjugated bilirubin
it is carried by proteins to the liver
small amounts may be present in the blood
what is conjugated bilirubin “direct”?
when unconjugated bilirubin gets sugars added to it in the liver
it enters the bile and passes from the liver to the small intestines and is eliminated in the stool
normally, no conjugated bilirubin is present in the blood
total bilirubin range?
0.3 - 1.9 mg/dL
conjugated + unconjugated
normal range of bilirubin?
0-0.3mg/dL
hepatocellular pattern of liver enzymes
increased AST and ALT compared to Alk phos, bili +/- elevated
Ex: intrahepatic injuries
Hepatocytes damaged -> ALT and AST released from cells