Acute Hepatic Failure

Question 1

What are the parameters of hyperacute, acute and subacute hepatic failure?

Answer 1

1. Hyperacute - 7 days or less
2. Acute - 8-12 days
3. Subacute - 4-26 weeks

Question 2

How is acute liver failure recognised?

Answer 2

1. Coagulopathy (INR >1.5) and encephalopathy.

2. More often on a background on cirrhosis = chronic liver failure.

Question 3

What are the infectious causes of acute liver failure?

Answer 3

1. Viral hepatitis (HBV, HCV, CMV)

2. Yellow fever

Question 4

Which drugs can cause acute liver injury?

Answer 4

1. Paracetamol
2. NSAIDs
3. Halothane
4. Anti-TB - rifampicin, isoniazid, pyrazinamide

Question 5

What is the main vascular cause of acute liver failure?

Answer 5

1. Alcohol
2. Fatty liver disease
3. Haemochromatosis
4. a1 antitrypsin deficiency
5. Primary biliary/sclerosing cholangitis

Question 6

What is this a presentation of?

Fatigue, bruising, bleeding, drowsy, confused, jaundice, hepatic encephalopathy, asterixis, constitutional apraxia.

Answer 6

Acute liver failure

Question 7

What is the management for acute liver failure?

Answer 7

1. Urinary catheter to assess fluid status
2. FBC, U&Es, LFTs, INR daily
3. 10% glucose IV, 1L 12 hours to avoid hypoglycaemia.
4. Treat cause (sepsis, GI bleed, paracetamol poisoning).
5. Thiamine and folate supplements
6. Treat seizures with phenytoin
7. Haemodialysis if renal failure develops
8. PPI cover for ulceration

Question 8

What are the complications of acute liver failure and how are they treated?

Answer 8

1. Cerebral oedema - mannitol IV on ITU
2. Ascites - fluid resuscitation, low salt diet, daily weights, diuretics.
3. Bleeding - vitamin K 10mg/day IV, platelets, FPP and packed RBC as needed.
4. Blind treatment of infection - ceftriaxone 1-2g/24rs IV
5. Hypoglycaemia - 50ml 50% dextrose IV
6. Encephalopathy - avoid sedatives, correct electrolytes, lactulose traps ammonia in colon

Question 9

What is the pathophysiology of hepatic encephalopathy?

Answer 9

Nitrogenous waste (ammonia) builds up in the circulation and passes to the brain, where astrocytes clear it by the process involving the conversion of glutamate to glutamine. Excess glutamine causes an osmotic imbalance and a shift of fluid into these cells (cerebral oedema).

Question 10

What are the four stages of hepatic encephalopathy?

Answer 10

1. Altered mood/behaviour, sleep disturbance, apraxia, poor arithmetic, no asterixis.
2. Increasing drowsiness, confusion, slurred speech, inappropriate behaviour/personality change +/- asterixis.
3. Incoherent, restless, asterixis, stupor (only responds to pain).
4. Coma