Acute and Chronic Liver Failure Flashcards Preview

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Flashcards in Acute and Chronic Liver Failure Deck (19)
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1
Q

What is acute liver failure?

A

Rapid deterioration in liver function (INR >1.5) and encephalopathy in setting of previously normal liver.

2
Q

Aetiology of acute liver failure?

A
  • Drugs (esp paracetamol)
  • Hep B / A
  • Ischaemic (circulatory shock; acute severe heart failure)
  • Idiosyncratic acute drug reaction
  • Idiopathic
3
Q

Mx acute liver failure?

A
  • Correct hypoglycemia
  • Monitor GCS
  • Prevent GI bleed w/ PPI
  • Monitor for infection, MODS
  • Consider Bx before INR too high
  • Exclude chronic liver disease
  • Transplant
4
Q

What are the major functions of the liver?

A
  • Synthesis of clotting factors
  • Glucose homeostasis; glycogen storage
  • Albumin synthesis
  • Bilirubin conjugation / clearance
  • NH3 metabolism (urea cycle)
  • Drug metabolism and clearance
  • Immune: dealing w/ gut derived bacteria and bacterial products
5
Q

T1/2 alb and significance of this?

A

Albumin half life =20d therefore can remain normal in acute liver injury

6
Q

Features of clotting profile (INR v APTT) in liver disease?

A

INR affected more by liver disease than APTT

7
Q

What is the liver enzyme pattern of hepatocellular injury / necrosis?

A
  • Elevation of ALT/AST

- Very high ALT in acute viral hepatitis, acute drug toxicity, ischaemia

8
Q

What is the liver enzyme pattern of intra- or extra-hepatic cholestasis?

A
  • Elevation of ALP and GGT
  • High ALP/GGT w/ minor elevation of transaminases typical of biliary obstruction, liver infiltration, cholestatic reactions to drugs
9
Q

What are the common causes of acute hepatitis?

A
  1. Acute viral hepatitis
  2. Drug related
  3. Ischaemic hepatitis
  4. Autoimmune
  5. Acute Budd Chiari
  6. Wilson’s disease
  7. Idiopathic
10
Q

What are the criteria for transfer to liver transplant unit?

A
  • INR >1.5 and rising
  • Any encephalopathy
  • Poor prognosis
  • Oliguria or creatinine > 200 umol/L
  • Acidosis with pH
11
Q

How can prolonged fasting interact with potential paracetamol toxicity?

A

Prolonged starvation an increase susceptibility to paracetamol poisoning by depleting hepatic glutathione stores.

12
Q

Prognosis of acute liver failure?

A
  • Survival >70%
  • Increased survival probably reflects availability of transplant as rescue therapy
  • highly dependent on aetiology and rate of progression
13
Q

How is liver transplant listing determined?

A

Using Kings College Criteria (KCC); different for ALF non-paracetamol v paracetamol.
-Identifies pts w/ poor prognosis who need transplantation.

14
Q

What is the role of Bx in acute liver failure?

A
  • Quantify extent of liver injury
  • Establish aetiology of liver injury
  • Guide Rx
15
Q

What are Kings Criteria for liver transplantation in FHF due to paracetamol od?

A
  • pH 100s
  • Cr >300umol/L
  • Grade III or IV encephalopathy
16
Q

What is the toxic dose of paracetamol at 24, 48 and >48h?

A

24: 200mg/kg or 10g (whichever is less).
48: 150mg/kg or 6g/day whichever is less
>48: 100mg/kg or 4g/day (whichever is less)

17
Q

Explain paracetamol metabolism and OD.

A

Usually paracetamol conjugated with glucuronide for excretion in bile. 5% forms NAPQI for conjugation with glutathione. Excess doses overwhelm glucuronide and glutathione systems, with unconjugated NAPQI producing hepatoxicity.

18
Q

How does N-acetylcysteine act to prevent hepatoxicity?

A

Acts as glutathione donor reducing production of NAPQI. 100% effective if administered within 8h.

19
Q

What are the causes of chronic liver disease?

A

Rule of 3s:

  • EtOH, HBV, HCV
  • Genetic: Wilson’s, Haeochromatosis, A1AT deficiency
  • AI: PBC, PSC, AI hepatitis
  • Other: NASH, Budd Chiari, drugs