Acute Liver Failure

Question 1

What is the definiton of acute liver failure?

Answer 1

Complex multisystemic illness occurring after an insult to liver, presenting with:
Jaundice 
Coagulopathy INR>1.5
Hepatic encephalopathy 
Absence of chronic liver 
<12wks

Question 2

How is ALF classified?

Answer 2

Hyperacute = <7days - best prognosis
Acute = 8-28days
Sub acute = 29days-12wks - worst prognosis

Question 3

What is the epidemiology of ALF?

Answer 3

Severe and rare
Mortality without transplant - 10-90%

Paracetamol = most common in UK
Viral hepatitis = most common in developing countries

Question 4

What other drugs can cause ALF?

Answer 4

Rifampicin, NSAIDs, valproate, carbamazepine, ecstasy, meow meow, anabolic steroids, Chinese herbalism

Question 5

What viruses cause ALF?

Answer 5

Viral hepatitis = hep A, E (50% worldwide) and B

Also HSV, CMV, EBV and parvovirus

Question 6

What are some rare causes?

Answer 6

Ischemic hepatitis 
Autoimmune hepatitis 
Acute fatty liver of pregnancy 
Wilson's disease 
Budd Chairi syndrome 
Mushrooms - amanita phaloides (death caps) 
Post hepatectomy 
Seronegative hepatitis = ???

Question 7

What are causes by time?

Answer 7

Hyperacute = paracetamol, other drugs, viral hep 
Acute = viral hep, ischemic hep (if presenting with shock too)
Subacute = seronegative, autoimmune

Question 8

What features are important in Hx and examination?

Answer 8

Hx:
Sexual - sex transmitted hep
Medication - what drugs? How many? Intentionally taking more or not?
FHx of liver disease

Examination:
Flap?
Drowsiness?
Can you do serial 7s?

Question 9

How should you investigate ALF?

Answer 9

Drug screen 
Viral antigens for hep - often IgM 
Autoantibodies, IgGs - autoimmune 
USS + uric acid + histology = acute fatty liver of pregnancy 
Platelets = HELLP
USS/venography = Budd-Chiari 
Imaging + histology = malignancy

Question 10

What factors may lead to poor prognosis?

Answer 10

Staggered paracetamol overdose
Malnourished
Alcohol excess

Also: chronic liver disease

Question 11

How do you manage ALF secondary to paracetamol overdose?

Answer 11

N-acetyl cystine - give NAC before taking levels

IV crystalloid fluids

Abx

Call transplant centre

Should be managed with senior input, ICU and transplant centre (for advice/prep)

Monitoring:
8hrly INR 
Venous gas - lactate and glucose 
Daily U+E and LFT 
No hepatic flap, can do serial 7's

Question 12

How do you manage ALF secondary to acute HBV infection?

Answer 12

Tenofovir

Inform transplant centre

Daily INR, U+R, LFT
No hepatic flap and 7s
USS abdo normal

Question 13

What complications of ALF?

Answer 13

Encephalopathy:
High levels of ammonia may result in cerebral oedema

Cardio respiratory:
Hypotension, ARDS, pneumonia

Renal failure:
Multifactorial

Sepsis:
Immune-suppressed
Bacterial (80%, fungal (30%)

Malnutrition:
Hypemetabolic state

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