Lec 26 Flashcards

1
Q

What is the definition of acute liver failure [3 parts/values]?

A
  • coagulopathy [INR > 1.5]
  • encephalopathy
  • jaundice < 24 wks duration

no underlying chronic liver disease

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2
Q

What is fulminant vs subfulminant acute liver failure?

A

fulminant = encephalopathy < 8 weeks

sub-fulminant = encephalopathy > 8 weeks

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3
Q

Most common cause of acute liver failure worldwide?

A

acute Hep B

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4
Q

Most common cause of acute liver failure in the US?

A

acetaminophen

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5
Q

What is pathophysiology of cerebral edema in hepatic failure?

A
  • excess NH3 to brain –> interacts wtih glutamate to form glutamine = has osmotic effect to draw water in
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6
Q

What is the difference hepatic encephalopathy and cerebral edema in hepatic failure?

A

hepatic encephalopahy = reversible chemical state

cerebral edema = physical condition of excess H20 in brain; occurs with late stages of hepatic encephalopathy

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7
Q

What is leading cause of death in patients with fulminant hepatic failure?

A

cerebral edema

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8
Q

What type of organisms primarily seen in sepsis with acute liver failure?

A

usually gram positive within 3 days of ICU stay

see fungal infections 2 wks after

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9
Q

What immuno defects in acute liver failure?

A

kupffer cell malfunction = macrophages of the liver

neutrophil malfunction

cell mediated immunity

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10
Q

What is pathophys of cardio dysfunction in acute liver failure?

A
  • low systemic and pulm vascular resistance with compensatory increase in CO and metabolic rate –> leads to tissue hypoxia and lactic acidosis production
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11
Q

What are signs of cardiac dysfunction in liver failure?

A
  • hypotension and tachycardia

- lactic acidsosi

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12
Q

What is mech of renal failure in liver failure?

A
  • direct nephrotoxicity OR hepatorenal syndrome
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13
Q

What is hepatorenal syndrome?

A
  • renal vasoconstriction secondary to systemic vasodilation seen in fulminant hepatic failure
  • functional abnormality but reversible with liver recovery/transplant
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14
Q

What clinical features of hepatorenal syndrome?

A
  • increased BUN and creatinine
  • decreased urine output

with background of hepatic failure

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15
Q

What is mech of hypoglycemia in liver failure?

A
  • defective gluconeogenesis

- inadequate hepatic uptake of insulin

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16
Q

What is treatment for acute liver failure due to tylenol toxicity?

A

N-acetylcysteine [NAC]

17
Q

What is treatment for acute liver failure due to mushroom?

A

penicillin G

18
Q

What zone of liver affected by acetaminophen?

A

centrilobular zone 3

19
Q

What is clinical presentation of acetaminophen induced fulminant hepatic failure?

A
  • N/V, ab pain
  • ALT/AST up to 10,000 within 12-24 hrs
  • long PT/INR
20
Q

What is kings criteria for acetaminophen induced acute liver failure?

A
pH < 7.3 
OR
- grade 3/4 encephalopathy
- INR > 6.5
- serum creatinine > 3.4
21
Q

What types of drugs implicated in acute liver failure?

A
  • antibiotics
  • herbals
  • CNS drugs
22
Q

What is effect of ALT/AST rice alone or ALT/AST + bilirubin elevation on prognosis?

A

worse prognosis if have bilirubin AND high ALT/AST

23
Q

What is normally the part of drug that causes hepatic injury?

A

the activtiy metabolite after phase 1 oxidation by CYP450

24
Q

What are some things that induce CYP?

A
rifampin
phenytoin
carbamazepine
phenobarbital
dexamethasone
alcohol
25
Q

How does alcohol use make acetaminophen liver tox worse?

A

because alcohol induces cyp450 –> more toxic metabolic

26
Q

When do you get hepatotoxicity with isoniazid?

A

usually after 1wk - 6 motnhs = have a latent period

27
Q

What drug is a common cause of cholestatic hepatotoxicity?

A

amoxicillin/clavulanic acid [augmentin]