Jaundice Flashcards
What are the liver tests/liver chemistry tests/liver enzymes?
AST/ALT (transaminase), alkaline phosphatase (ALP) and bilirubin, LDH and GGT
Markers of liver damage, not a marker of liver function
What are some examples of true liver function tests?
PT/INR, albumin, cholesterol and ammonia
What is hepatocellular?
Primary injury is to the hepatocytes
Primary AST/ALT elevation
ALT is more specific for livery injury than AST
What is cholestatic?
Primary injury is to the bile ducts
Primarily alkaline phosphatase and bilirubin elevated
- failure of bile to reach duodenum
- jaundice and pruritus
- pure cholestasis (no signs of hepatocellular necrosis)
Bilirubin provides an indication of what?
Hepatic uptake, metabolic (conjugation) and excretory functions (fractionate to get conjugated vs unconjugated)
What are the aminotransferases?
Aspartate aminotransferase (AST) and alanine aminotransferase (ALT)
Sensitive indicators of liver cell injury
When do changes in AST and ALT occur?
Greatest elevations seen in hepatocellular necrosis (e.g. viral hepatitis, toxic or ischemic liver injury, acute hepatic vein obstruction)
Occasionally with sudden complete biliary obstruction (from gallstones)
Milder abnormalities in cholestatic, cirrhotic, and infiltrative disease
Poor correlation between degree of liver cell damage and level of aminotransferases
EtOH induced liver injury usually produces modest increases with more prominent elevation of AST than ALT (2:1)
Why is ALT a more specific measure of liver injury than AST?
Because it is also found in striated muscle and other organs
Describe alkaline phosphatase
Sensitive indicator of cholestasis, biliary obstruction (enzyme increases more quickly than serum bilirubin) and liver infiltration
Mild elevations in other forms of liver dz; limited specificity bc of wide tissue distribution
Elevations also seen in normal childhood, pregnancy and bone disease
What is GGT?
Gamma-glutamyl transpeptidase
Correlates with serum alkaline phosphatase activity
Elevation think liver
Normal think other source (bone/placenta)
What is the single best acute measure of hepatic synthetic function?
Coagulation factors
Prolongation results from factor deficiency or inactivity
All clotting factors except for factor VIII are synthesized in the liver
Helpful in diagnosis and prognosis of acute liver disease
INR commonly used for this
Describe albumin
Decreased serum levels result from decreased hepatic synthesis (chronic liver disease or prolonged malnutrition)
Excessive losses in urine or stool
Insensitive indicator of acute hepatic dysfunction, bc serum half life is 2-3 weeks
In pts with chronic liver disease, degree of hypoalbuminemia correlates with severity of liver dysfunction
Describe ammonia
Elevated blood levels result from deficiency of hepatic detoxification pathways and portal systemic shunting (ex. Cirrhosis)
Elevation of blood ammonia doesnt correlate well with hepatic function or the presence or degree of acute encephalopathy
What is jaundice?
Yellow skin pigmentation caused by elevation in serum bilirubin level (termed icterus) (hyperbilirubinemia)
Often more easily discernible in sclera as well as oral mucosa and palms
Hyperbilirubinemia occurs as a result of what?
Overproduction
Impaired uptake, conjugation, or excretion of bilirubin
Regurgitation of unconjugated or conjugated bilirubin from damaged hepatocytes or bile ducts
What are the first steps for jaundice?
What is the Hx/PE for jaundice?
What are the diagnostics for jaundice?
What is the tx/management for jaundice?
