Acute liver failure

"Sudden loss of hepatic function in a person without pre-existing liver disease"

Classification

• Fulminant - development of encephalopathy within 8/52 of development of symptoms
• Subfulminant - have had liver disease for up to 26 weeks before encephalopathy

Causes

• Drugs - paracetamol, flucloxacillin, anaesthetic agents
• Budd-Chiari
• Malignancy
• Fatty liver disease of pregnancy
• Wilson's disease
• HAV
• Autoimmune hepatitis
• Ischaemic hepatitis
• HBV

• Clinical course
  • Sudden loss of functional hepatocyte mass
  • Portal HTN
  • Encephalopathy, coagulopathy, renal failure, sepsis
  • MODS often occurs
  • Death occurs from cerebral oedema of infection

Complications

• Encephalopathy

Grade	Mental status	Asterixis	EEG
I	Euphoria/depression	Yes/no	Usually normal
	Mild confusion
	Slurred speech
	Disordered sleep
II	Lethargy	Yes	Abnormal
	Moderate confusion
III	Marked confusion	Yes	Abnormal
	Incoherent
	Sleeping but arousable
IV	Coma	No	Abnormal

• Cerebral oedema - common cause of death - secondary to ammonia, however lactulose doesn't help
  • Decrease ICP to below 20-25mmHg - elevate head of bed, minimise stimulation, mannitol, hyperventilation
  • Maintain cerebral perfusion pressure >50-60mmHg
  • Once increased ICP develops, ominous sign. If it's visible on CT, likely irreversible damage, and transplant contraindicated.
  • ICP monitors may or may not stack up - risk of haemorrhage.
• Coagulopathy
• Metabolic abnormalities
  • Hypokalaemia
  • Hyponatraemia
  • Hypophosphataemia - paracetamol-induced liver failure
  • Hypoglycaemia
• Renal failure
• Pulmonary dysfunction - oedema and pnuemonia
• Seizures
  • Treat with phenytoin

Determining need for transplant

• Kings College criteria
  • Attempts to define those patients who are going to die without transplant
  • Paracetamol overdose criteria: a bit too inclusive for paracetamol overdose - many patients meeting these criteria do not go on to need transplant
    • pH <7.3 or
    • INR >6.5 and serum creatinine >300
  • The non-paracetamol criteria are still valid though
    • INR >6.5 or three of:
    • INR >3.5
    • Bilirubin >301
    • Age <=10 or >40
    • Cause of drug toxicity
    • Time from onset of jaundice to encephalopathy >7 days

See also separate topic 'liver transplant'