Hepatic Failure

Question 1

What does an INR > 1.5 indicate?

Answer 1

Coagulopathy - bleeding disorder where the blood’s ability to coagulate is impaired

Question 2

What are the different categories of acute hepatic failure?

Answer 2

Hyper-acute => onset ≤ 7 days
Acute => 8-12 days
Subacute => 4-26 weeks

Question 3

What are the risk factors of Hepatic failure?

Answer 3

• Tattoos and piercings
• Blood transfusions
• Unprotected sex
• Shellfish
• Heavy alcohol consumption
• Exposure to other people’s bodily fluids

Question 4

What are the clinical features of hepatic failure?

Answer 4

= Triad:

• Encephalopathy (seen by liver flap)
• Jaundice
• Coagulopathy

=> Sweet and fecal breath may be present

Question 5

What is Hepatic encephalopathy?

Answer 5

Decline in brain function that occurs as a result of severe liver disease

Question 6

What is the pathophysiology of hepatic encephalopathy?

Answer 6

• Ammonia buildup due to liver failure
• Passes brain in circulation and is broken down to form glutamine
• Excess glutamine changes osmotic balance casuing water shift into the brain hence cerebral oedema

Question 7

What are the different grades of hepatic encephalopathy?

Answer 7

=> Grade I

• Altered mood
• Sleep disturbance
• Dyspraxia
• NO LIVER FLAP

=> Grade II

• Inappropriate behaviour
• Increased drowsiness
• LIVER FLAP

=> Grade III

• Incoherent
• LIVER FLAP

=> Grade IV

• Coma

Question 8

What is the management of hepatic encephalopathy?

Answer 8

• Treat underlying cause
• Lactulose is first line. Addition of rifaximin as secondary prophylaxis
• Other options include liver transplantation in selected patients

Question 9

What are the causes of hepatic failure?

Answer 9

=> Causes can be categorised into:

• Infectious
• Drugs
• Toxins
• Vascular

=> Infectious

• Viral Hepatitis (B and C)
• CMV
• Yellow fever
• Leptospirosis

=> Drugs:

• Paracetemol overdose
• Halothane
• Isoniazid (TB drug)

=> Toxins:

• Amanita Phalloids mushrooms
• Carbon Tetrachloride

=> Vascular:

• Badd-Chiori syndrome
• Veno-occlusive disease

Question 10

How does paracetamol overdose cause hepatic failure?

Answer 10

• Paracetamol is usually metabolised by liver through glucuronidation and sulfation
• Toxic intermediate is produced, NAPQ1, which is conjugated with gluathione
• In cases of overdone, gluathione stores are depleted, meaning toxic intermediate levels rise

Question 11

What is the management of paracetamol overdose?

Answer 11

• Patients who present within 1 hour of overdose may benefit from activated charcol, to reduce absorption of drug

=> Criteria for IV acetylcyteine:
- Staggered overdose or time since overdose is unknown
OR
- Above treatment line
- If anaphylactoid reaction develops, infusion is stopped and started again at a lower dose

=> Criteria for liver transplantation:
- Arterial pH < 7.3 24 hours after overdose
OR ALL THE FOLLOWING:
- prothrombin time > 100 seconds
- creatinine > 300 umol/l
- grade III OR IV encephalopathy

Question 12

What are the investigations in suspected hepatic failure?

Answer 12

=> Blood tests

=> Urinalysis

=> Ascitic tap

=> CXR

=> Abdominal ultrasound

Question 13

What are the main drugs that are considered hepatotoxic?

Answer 13

• Paracetamol
• Methotrexate
• Isoziazid
• Azathioprine
• Phenothiazines
• Oestrogen
• Tetracycline

Question 14

What is the management of hepatic failure?

Answer 14

• Treat the underlying cause
• Alway protect airway
  Insert catheter to monitor fluid status
• monitor vitals and take daily weights
• Take blood tests daily. Check blood glucose and give IV glucose to prevent hypoglycaemia
• Avoid hepatotoxic drugs
• If seizures occur, treat with phenytoin
• Consider PPIs in cases of stress ulcers

Question 15

What is the underlying diagnosis when Liver failure occurs following cardiac arrest?

Answer 15

Ischaemic Hepatitis