Acute liver failure Flashcards
What is the definition of Acute liver failure?
Acute liver failure:
- An increase in PT by 4-6 seconds (INR >1.5)
- and the development of hepatic encephalopathy
- in a patient without pre-existing cirrhosis and with an illness of <6 months duration.
What is the most common cause of acute liver failure?
Paracetamol overdose
What is the pathophysiology of paracetamol poisoning resulting in acute liver failure?
Paracetamol, often conjugated in the liver into 2 harmless metabolites - sulfate and glucuronide conjugates.
In overdose, liver metabolise paracetamol in a different pathway - producing the toxic metabolite NAPQI, which is inactivated by glutathione. However, glutathione becomes depleted in
Who are at high risk of acute liver failure after paracetamol overdose?
Patients with malnutrition, or taking CP3A4 enzyme inducers - Rifampicin, Phenytoin, Phenobarbital, Carbamazepine, St John’s wort.
Why are those with malnutrition at high risk of paracetamol overdose toxicity?
They have less stores of glutathione, which helps convert toxic NAPQI to a non-toxic metabolite.
What are the presenting signs of hepatic necrosis?
- Hepatic encephalopathy
- Oliguria
- hypoglycaemia
- Lactic acidosis
- Renal failure, usually by day 3
What is the treatment for paracetamol overdose?
Acetylcysteine.
What are the effects of decreased liver function?
- Gluconeogenesis - hypoglycaemia
- Lactate clearance - lactic acidosis
- Ammonia clearance - increased ammonia
- coagulopathy issues
What are the differential diagnosis of abnormal transaminases?
Vascular - Hypotension, Congestion, HAT
Viral - Hepatitis A, B, C, D, E, EBV, CMV, HSV, PMV
Drugs and toxins - Paracetamol (acetaminophen), NSAIDs, statins, B cereus toxins.
What are the complications of acute liver failure?
Hepatic encephalopathy, cerebral oedema, Intracranial hypertension.
Pancreatitis, especially in acetaminophen-related disease
Renal failure
Adrenal glands - decreased glucocorticoid production, leading to hypotension
What is a potential cause of cerebral oedema?
Due to increased ammonia, which are converted to glutamine. Accumulated glutamine leads to increased water accumulated in cells, causing cerebral oedema
