Path-Liver Dz Flashcards
when the liver regenerates, how does the anatomy, histo, and function change?
it doesn’t, it returns to normal
what is the most common cause of acute liver failure?
drugs (and toxins)
what drugs usually cause liver failure?
acetaminophen, and then new drugs on the market
this can cause acute liver failure, but usually causes chronic liver failure
viral hepatitis
what actually happens in drug-induced liver injury (DILI)? (3 possibilities)
1) toxic rxn to drug or more commonly drug metabolite, 2) inflamm immune rxn to drug, 3) drug hepatitis
what are the two classes of hepatotoxic drugs?
1) intrinsic, 2) idiosyncratic
what is an intrinsic drug injury?
injury is predictable and dose dependent (example: acetaminophen, other toxic metabolites)
what is an ideosyncratic drug injury?
injury not predictable or dose-dependent (ABX, herbal)
which two pathways of tylenol metabolism result in non-toxic, water-soluble metabolites?
glucuronidation & sulfation
metabolism of tylenol by the ____ system produces an alkylating metabolite, _____, that is directly toxic to the liver
cytochrome P-450; NAPQI
under non-toxic levels of tylenol administration, what happens to the minute fraction of NAPQI that is formed?
immediately and irreversibly conjugated with sulfhydryl groups of glutathione and rendered nontoxic (excreted by kidneys)
when the amount of unconjugated NAPQI depletes glutathione stores, what happens to the excess?
covalently binds to and inactivates hepatocyte proteins, causing cell death
how do you treat an acetaminophen overdose?
N-acetylcysteine replenishes depleted glutathione
how does chronic alcoholism affect the metabolism of tylenol?
it induces cytochrome P-450, thus increasing the amount of toxic metabolite formed (toxicity at a lower dose!)
which zone of hepatocytes are most sensitive to hepatotoxic injury?
zone 3/perivenular (closest to central vein, farthest from portal area and thus hypoxic and malnourished)
moderate tylenol overdose leads to (reversible/irreversible) hepatocyte injury to zone ___ hepatocytes
reversible; zone 3 only
severe tylenol overdose leads to (reversible/irreversible) hepatocyte injury to zone ___ hepatocytes
irreversible; all zones (need transplant)
when hepatocytes die from tylenol overdose, histology shows?
centri-lobular coagulative necrosis (pink ghost cells)