LFT Flashcards
Cholestatic liver disease
injury to bile ducts and/or bile flow obstruction
infiltrative liver disease
liver is invaded or replaced by non-hepatic substances
What liver function tests reflect hepatocellular damage
- ALT: Alanine aminotransferase
- AST: aspartate transaminase
Which liver function tests reflect a cholestatic process
- total biliruben
- alkaline phosphatase
- GGT
What does an elevated alkaline phosphatase suggest
- cholestasis: bile cannot flow
- liver, bone, intestine, placenta origin
What can be used to distinguish between liver and bone disease when there is an elevated alk phosph
ALP isoenzyme
What is an enzyme in the liver and is elevated in diseases affecting the biliary tree and can help distinguish liver as the origin.
5NP (5’-Nucleotidase)
fractionated biliruben
tells the fraction of total bilirubin that is direct vs indirect
What condition presents with these lab results
- direct (conjugated) biliruben: elevated
- indirect biliruben: elevated or normal
- AST/ALT: elevated
liver disease
What condition presents with these lab results
- direct (conjugated) biliruben: normal
- indirect biliruben: elevated (90% of TB)
- AST/ALT: normal
- anemia, increased reticulocyte count
hemolysis
What condition presents with these lab results
- direct (conjugated) biliruben: normal
- indirect biliruben: elevated (90% TB)
- AST/ALT: normal
- no anemia
gilbert syndrome: inherited decrease in ability to conjugate biliruben
GGT is present in
- hepatocytes
- biliary epithelial cells
When is GGT useful
- when ALP is elevated, it confers liver specificity
- __elevated with biliary tract obstruction or cholestasis
- when AST/ALT > 2, it further supports Alcoholic liver disease when elevated
Which liver function tests reflext liver function
- albumin
- PT/INR
Which is more specific to the liver, ALT or AST
ALT
- AST found in liver, skeletal and cardiac muscle, RBC
The first step in the evaluation of a patient with elevated LFTs but no symptoms is to
repeat the test
Non hepatic source of biliruben
RBC
Non hepatic source of AST
- skeletal muscle
- cardiac muscle
- RBC
Medications that are common examples to cause harm to the liver
- acetaminophen
- statins
- azoles
- NSAIDs
- Isoniazid
Mildly elevated AST and ALT (2-5 x nml) generally indicates what conditions
- fatty liver
- ETOH related
- chronic viral hepatitis
- medication effect
Elevated AST generally indicates what conditions
- alcoholic hepatitis
- skeletal
- cardiac
AST: ALT ratio > 2 indicates
- alcoholic liver disease
AST: ALT ratio < 2 indicates
- acute or chronic viral hepatitis
- chrolestatic disease (ALP elevated)
- NASH (ration usually < 1)
If AST and ALT are higher than ALP, this is typical of
hepatocellular injury
If ALP is higher than AST and ALT, this is typical of
Cholestatic
If ALP is elevated with near normal AST and ALT, this is indicative of
- cholestatic or infiltrative
Nonalcoholic fatty liver disease has what spectrum of disease
- simple steatosis (NAFL)
- non-alcoholic steatohepatitis (NASH)
- cirrhosis
simple steatosis or Non-alcoholic fatty liver means what
- fatty liver without injury of hepatocytes on liver bx
- risk of progression to cirrhosis is minimal
Non alcoholic steatohepatitis (NASH) means
- fatty liver + inflammation + hepatocyte injury on liver bx +/- fibrosis
- risk of progression of fribrosis, cirrhosis, liver failure and liver cancer is significant
risk factors for Non alcoholic steatohepatitis (NASH)
- metabolic syndrome
- abdominal obesity
- hyperlipidemia (high TG or low HDL)
- DM (insulin resistance)
how is Non alcoholic steatohepatitis (NASH) diagnosed
- mildly elevated aminotransferases (AST, ALT)
- fatty infiltration on imagina
- confirmed by liver bx
- fat accumulation and inflammation
managment for Non alcoholic steatohepatitis (NASH)
- exercise
- weight loss
- discontinue ALL ETOH
- control diabetes and hyperlipidemia
Which two autoimmune liver diseases affect women: men 9:1
- primary biliary cirrhosis
- autoimmune chronic hepatitis
What is primary biliary cirrhosis
- immunologic attack on the intrahepatic bile ducts that eventually leads to cirrhosis and liver failure
AMA (anti-mitochondrial antibodies) is positive in which condition
primary biliary cirrhosis
What is autoimmune chronic hepatitis
- hepatocellular inflammation secondary to presumed T cell mediated immune attack of liver antigens
Which autoimmune liver disease affects men: women 5:1
primary sclerosing cholangitis
what is primary sclerosing cholangitis
- inflammation and fibrosis of the intrahepatic and extrahepatic bile ducts
- strong association with IBD
- can lead to cirrhosis and liver failure
What antibody tests are available when assessing for autoimmune hepatitis
- antinuclear antibodies (ANA)
- smooth muscle antibodies (SMA)
- liver kidney microsomial antibody (LKMA)
- antibody to liver cytosol (Anti-LC1)
which condition presents with
- AST/ALT 7-10 x ULN
- ASMA 90% positive
- IgG: high titer
autoimmune hepatitis
which condition presents as
- ALP 2-10 x ULN
- biliruben elevated in later disease
- AMA positive
- IgM (high titer)
primary biliary cirrhosis
What is Hereditary hemochromatosis
- autosomal recessive
- genetic mutation results in increased GI absorption of iron -> iron accumulation
Hereditary hemochromatosis can lead to what 2 liver conditions
- cirrhosis
- esp in patients who drink ETOH
- hepatocellular carcinoma
how is hepatocellular carcinoma screened for
- AFP (alpha fetoprotein)
- US
Lab findings in hereditary hemochromatosis
- LFTs
- serum Fe
- TIBC
- ferritin
- elevated LFTs: AST, ALT, Alk Phos
- Fe/TIBC = transferrin saturation
- transferrin sat > 45 and/or
- ferritin > 250 in men or > 200 in women
- proceed to HFE mutation analysis
how is hereditary hemochromatosis diagnosed
- genetic testing
- liver bx
treatment for hereditary hemochromatosis
- avoid vit c and iron supplements
- avoid ETOH
- regular phlebotomy
What disease should be suspected in a patient with COPD/emphysema at a young age (30-40s)
alpha-1 antitrypsin defciency
how is alpha-1 antitrypsin defciency diagnosed
- absence of alpha 1 peak on SPEP
- serum a-1 antitrypsin decreases
- a-1 antitrypsin phenotype
alpha 1 antitrypsin is synthesized where
liver
What is Wilson’s disease
- autosomal recessive
- accumulation of copper in liver and decreased excretion of copper into bile
- presents between ages 5-35
in Wilson’s disease, serum ceruloplasmin is
- low
- serum ceruloplasmin is the plasma copper-carrying protein
- < 5 is strong evidence for WD
clinical manifestations of Wilson’s disease affect what systems
- hepatic
- neurologic
- psychiatric
Kayser-Fleischer ring is pathognomonic for
Wilson’s disease
- Kayser-Fleischer ring: fine pigmented granular deposits in cornea
how is Wilsons disease diagnosed
- liver biopsy
How is Acute Hepatitis A spread
- fecal oral route
- consumption of shellfish or uncooked fruits, vegetables
what lab value is diagnostic for Acute Hepatitis A
- positive Anti-HAV IgM
- AST/ALT > 15 x
- elevated ALP and bilirubin
can Hepatitis A become chronic
no
main symptoms of Acute Hepatitis A
- fever
- jaundice
- 90% childhood infection and 50% adult infections asymptomatic
- 99% recover completely
How is Hepatitis B transmitted
- blood
- sexual contact
- parenteral contact
- peri-natal transmission
clinical presentation
- arthralgia, rash
- jaundice
- elevated biliruben, ALP, ALT > 15x
Hepatitis B
75% of chronic HBV carriers are
Asian
What antigen tests are elevated in hepatitis B
-
Hepatitis B surface antigen (HBsAg)
- active disease
-
Antibody to surgace antigen (Anti-HBs)
- immunity (vaccine or resolved infection)
-
Antibody to hepatitis B core antigen
- IgM anti-HBc: acute exposure
what percentage of patients whi Hep B develop a chronic infection
1-10%
what percentage of patients whi Hep C develop a chronic infection
70-80%
Hep C testing
- HCV antibody -> if reactive
- HCV RNA -> detected -> current infection
