Gastro - ALF

Question 1

Define acute liver failure

Answer 1

Rare life threatening illness in patients without pre existing liver diseaseA triad of Jaundice Encephalopathy Coagulatopathy

Question 2

How is ALF classified

Answer 2

O Grady SystemTiming is based on interval from jaundice to encephHyperacute - <1 weekActe 1-4 weekSub acute 4-12 weeks

Question 3

Causes of ALF

Answer 3

Infections - Heps A-E, HSV, CMV, EBV, VZVMalignancyVascular - Budd Chiairi (hep vein thrombus) Ischaemic hepatititsPregnancy - HELLP, acute fatty liverMetabolic - WilsonsOther - Auto immuneMushroom poisoningDRUGS - Paracetamol, phenytoin, isoniazid, St Johns Wort, ectasy, amphet, chemo

Question 4

What are the King’s College Criteria

Answer 4

Prognostic tool for patietns with liver failureIdentify who has a high risk for mortality andAsceratin suitability for transplantDivided in PARACETAMOL and NON PARACETAMOL

Question 5

Kings Criteria - Paracetamol

Answer 5

pH < 7.3 (after 24 hours fluid resus)ORHepatic enceph grade 3-4PT > 100 secondsCr > 300umolORLacate >3.5 at 4 hours OR 3 at 12 hours *after fluid resus

Question 6

Non paracetamol kings criteria

Answer 6

PT > 100 secondsOR3 of:

PT >50sBili >300Non Hep A/B aetiologyAge <10 or >40Onset from jaundice to enceph > 7 days

Question 7

How does ALF present

Answer 7

General - malaise, nausea, jaundiceEncephalopathyHigh Cardiac output state, reduced SVRVasoplegia from inflammatory cascade, AKI and oedema

Question 8

Grading of Enceph

Answer 8

West-Haven Criteria Grades 1-4 (some books say 0)1 - lack of awareness, eurphora, anxiety, short attention2 - Lethargy, disorientation, inapproriate3 - Somnolence, semi-stupour, confusion, grossly disorientated4 - coma

Question 9

Mechanism of renal failure in ALF

Answer 9

1) ATN from hypovolaemia, hypotension, hypoperfusion and nephrotoxins
2) Underlying disease - glomerularlynephritis in HBV/C
3) Ascites cause intra ab hypertension
4) HRS

Question 10

Management of ALF by system

Answer 10

Resp - Grade 3/4 enceph –> I&V Avoid excess PEEP (increases hepativ venous pressure and ICP)
Renal - RRT early in the face of fluid overload and met acidosis
Neuro - Protective measures - Head up, loose ties, MAP 75 (CPP 60-80) Avoid hypoxia/hypercapnoea, fever, Sugars at 4-10mmol/L
CVS - low SVR, fluid resus, vasopressors
Coag - If bleeding replace approrpirately with factors HOWEVER routine correction not advised - PT is a prognostic marker

Question 11

The liver makes all factors except?

Answer 11

Factor 8

Question 12

Mechanism of paracetamol overdose

Answer 12

Normal - paracetamol is glucornidated and suphated by liver.Small amount made by cp450 system –> makes NAPQINAPQI then detoxed by glutathioneOD - gluc/sulph is overwhelmed and saturatedMore and more cp450 —> more NAPQIGlutathoine stores depletedNAPQI causes cellular damage

Question 13

Risk factors of paracetamol toxicity

Answer 13

Cytochrome enzyme induction AND Glutathione depletion
Cyto - Chronic alcoholism
Enzyme inducers - st johns, carbamazepine, rifampicin, isnoniazind

Glutathion
- malnutrition, eating disorder other liver injury
- viral hep, alcohol hep

Question 14

Treatment of paracetmaol OD

Answer 14

NAC - precursor to glutathione and replenishes stores.Effective within 8 hoursMeasure serum paracetamol and plot on Rumack Matthew Nomogram