2+ Acute Liver Failure

Question 1

What is acute liver failure?

Answer 1

ALF is a rapid decline in hepatic function characterised by jaundice, coagulopathy (INR >1.5), and hepatic encephalopathy in patients with no evidence of prior liver disease.

• If it occurs in a patient with pre-existing liver disease, the term
  acute-on-chronic liver failure is used

Question 2

How do you classify acute liver failure now?

Answer 2

Classified by interval from onset of jaundice to development of hepatic encephalopathy:
- Hyperacute = within 7 days
- Acute= between 8 and 28 days
- Subacute= between 29 days and 12 weeks
- Acute-on-chronic

Question 3

How was acute liver failure classified previously?

Answer 3

Still based on the interval from onset of jaundice to development of hepatic encephalopathy:

Fulminant if within 8 weeks
Late-onset if between 8 and 26 weeks

Question 4

What is the epidemiology of acute liver failure?

Answer 4

Not actually very common

Question 5

What is the aetiology of acute liver failure?

Answer 5

Infectious
Drugs/Toxins
Other: alcohol, metabolic, genetic, AI, pregnancy
Vascular

Question 6

What is the pathophysiology of acute liver failure?

Answer 6

• Characterised by massive hepatocyte necrosis –> organ failure
• Hepatocyte necrosis and apoptosis may co-exist and ALF can
  occur without histological evidence of hepatocellular necrosis

Question 7

What are the risk factors for acute liver failure?

Answer 7

• Age >40, female, poor nutrition, pregnancy, chronic Hep B,
  paracetamol
• Hepatotoxic medication
• Chronic alcohol misuse

Question 8

What is the clinical presentation of acute liver failure?

Answer 8

• Jaundice
• Hepatic encephalopathy
  o Asterixis, hypertonia, hyperreflexia, positive Babinski sign,
  nystagmus, EPS: bradykinesia, slow speech, dyskinesia
  o Altered mood, behaviour, sleep disturbance, confusion,
  drowsiness, coma
• Abdominal pain
• N/V
• Malaise
• Cerebral oedema: headache, neck pain/stiffness
• Signs of chronic liver disease: palmar erythema, spider naevi,
  splenomegaly, ascites, fetor hepaticus

Question 9

What biochemical investigations do you do when you suspect acute liver failure?

Answer 9

• LFT: hepatocellular damage, elevated GGT
• Coags: High PT/INR
• UEC: decreased albumin, renal failure is a complication,
  hyponatremia is common and worsens as disease progresses
• Metabolic panel: Mg, K, PO4
• FBC
• Lipase to rule out pancreatitis
• ABG: acidosis for px
• Tox screen/ paracetamol levels

Question 10

What microbiological investigations do you do when you suspect acute liver failure?

Answer 10

• Hepatitis serology
• Blood culture
• Ascitic tap culture
• Urine culture

Question 11

What imaging can you do when you suspect acute liver failure?

Answer 11

CXR: assess for aspiration pneumonia (many patients with hepatic encephalopathy), pulmonary oedema

Abdominal USS with Doppler: check for hepatic vessel thrombosis in Budd-Chiari syndrome, hepatomegaly, splenomegaly, hepatic surface nodularity

CT head considered once grade 3-4 hepatic encephalopathy develops to assess for presence of cerebral oedema –> can also do a transcranial doppler to check for intracranial HTN

Question 12

What is the DDx of acute liver failure?

Answer 12

Severe acute hepatitis
Cholestasis
Haemolysis

Question 13

How do you manage acute liver failure?

Answer 13

1. ICU as soon as encephalopathy presents
2. Assess for liver transplant need
3. Neurological status monitoring: in stage 3 and 4 may progress to cerebral oedema and intracranial HTN
4. Monitor BSL, electrolytes and cultures (blood, urine, sputum and ascites if needed)
5. No hepatotoxic medications
6. Give lactulose to minimise the hyperammonaemia

Treat underlying cause:
- Acetylcysteine for paracetamol
- Anti-virals for HSV
- Prednisolone for AI hepatitis
- Tenofivir for Hep B
- Anticoagulation + TIPS for Budd-Chiari
- Decrease serum copper for Wilson’s
- Pregnancy (acute fatty liver or haemolysis + HELLP syndrome) deliver fetus

Treat complications
- Ascites: decrease salt and fluid intake
- Bleeding: vit K
- Encephalopathy: avoid sedatives, correct electrolytes

*Patients with ALF who fulfil listing criteria are category 1A for liver allocation

Question 14

What are the complications of acute liver failure?

Answer 14

• Rapidly progressive hepatic encephalopathy –> risk of cerebral oedema and raised intracranial pressure. Once it progresses, elective tracheal intubation should be performed
• Coagulopathy: only correct with Vit K if significant bleeding occurs or prior to procedures
• Infection
• Renal failure and haemodynamic changes (hepatorenal syndrome, hypovolaemia, acute tubular necrosis)
• Metabolic disorders: acid-base disturbances, hyponatremia, magnesium, potassium, phosphate and glycaemia (impaired GNG and hepatic glycogen production)
• Cerebral oedema
• GIT bleeding