4 - Jaundice & LFTs Flashcards
Elevated ALT - Cause
I don’t fucking know. That shit just happens sometimes
15% of patients with Chronic Liver disease (HCV or NAFLD)
Have NORMAL liver tests despite having histologic damage
New Recommendations for the cut off for aminotransferases
Men - 31
Women - 30
Dangerzone - Hepatocytes
Well-differentiated 80% of cytoplasmic mass Have the ability to replicate in injury Secrete bile acids Take up digested material Synthesize albumin Metabolize and detoxify exogenous compounds
Dangerzone - Biliary Tree
Bile is secreted by hepatocytes
Cholestasis is caused by alterations in microfilaments surrounding bile canaliculus
Alterations can be induced by toxins, infection or obstruction
Obstruction may be intrahepatic or extrahepatic
Liver Functions
Measure of SYNTHETIC activity, not inflammation!!!!!!
“True” liver function tests measure
Protein synthesis (albumin, coag factors)
Nutrient Metabolism (Gluconeogenesis - the last thing to go)
Biotransformation (bilirubin glucoronidation)
Immune Defense
Bile Acid Synthesis
Synthetic Function Tests
PT - Production of coag factors
Most have half-lives between 6 - 96 hours and prolonged within a day with hepatic synthetic dysfunction
Albumin - Produced in hepatocytes half life is 20 days but not specific can be abnormal because of the other factors that can lower, including poor nutrition,
Bilirubin Test
Can be a marker of impaired synthetic function
Labs - Bilirubin
Breakdown product of heme cells released from senescent red blood cells and from hemoprotein in the liver
Natural compound circulates with albumin and is taken up by liver and secreted in the bile
If bile secretion is impaired, conjugated bilirubin may leak into plasma and cause jaundice
Alkaline Phosphatase
A family of isoenzymes that catalyze the hydrolysis of phosphatase esters
Found in liver, bone, intestine, placenta, kidney, leukocytes
In liver associated with sinusoidal and canalicular membranes
Obstruction to bile flow causes an increase in AP secondary to the induction of AP synthesis
Aminotransferases (AST, ALT)
Naturally found in the serum at low levels
AST is also found in cardiac muscle, skeletal muscle, kidney, pancrease, lungs, leukocytes
Both enzymes are released in the blood in increasing amounts when the hepatocyte membraen is damaged
Correlated in injury byt not to chance of recovery
INR of 2
Bad
γGlutamyl Transpeptidase (GGT)
Catalyzes transfer of glutamyl groups of peptides suc has glutathione to other amino acids
Found in liver, kidney, seminal vesciles, liver, spleen, heart, brain, not bone
VERY SENSITIVE, limited specificity
AST - Location
Mitochondria and cytosol of hepatocytes, heart and muscle
ALT - Location
Cytosol of hepatocytes
Alk Phos
Microvilli of the bile canaliculi, bone, placenta
Hepatocellular Pattern
AST +++ ALT +++ Alk Phos + TB + GGT +
Cholestatic Pattern
AST + ALT + Alk Phos +++ TB +++ GGT +
Infiltrative Pattern
AST + ALT + Alk Phos +++ TB + GGT +
Ultrasound - Use
Biliary Obstruction, Masses, Vasculature
$
Biliary Tree:
Rule out obstruction
Evaluate for presence of stones
Vasculature:
Evaluate flow, rule out obstruction
Screen for thrombus
Screen for stricture
CT or MRI/MRCP - Use
HCC, Mets
$$
3D imaging Demonstrates morphology of the liver Evaluate for size, position Evaluate for bleeding Evaluate for tumors, both benign of malignant
Will not evaluate for liver function and is not sensitive enough to detect fibrosis of the liver
Rarely reveals exact etiology of disease
ERCP - Use
Evaluate and Treat Biliary Obstruction
$$$$
Endoscopic cannulation of the ampulla with injection of contrast into the biliary tree
Diagnosis and therapy
EUS
Endoscopy using ultrasound technology to locate masses, lymph nodes, evaluate bile ducts
