Liver failure

Question 1

Define acute liver failure.

Answer 1

Rapid decline in hepatic function characterised by…

• jaundice
• coagulopathy INR>1.5
• hepatic encephalopathy

… in patients with no prior liver disease.

Question 2

Define liver failure.

Answer 2

Severe liver dysfunction leading to jaundice, encephalopathy and coagulopathy.

Can be classed as hyperacute, acute, subacute and acute-on-chronic.

Question 3

Define chronic liver failure.

Answer 3

Deterioration in liver function superimposed on chronic liver disease. Stable chronic liver disease is defined by:

• Palmar erythema
• Dupyutren’s contracture
• Spider naevi
• Gynaecomastia

May also be called ‘decompensation’.

Question 4

What are the 4 main biochemical features of liver failure?

Answer 4

Failure of:

• Synthetic function
• Clotting factor and albumin
• Clearance of bilirubin
• Clearance of ammonia → encephalopathy → asterixis

Question 5

How do you classify acute liver failure?

Answer 5

Hyperacute - jaundice with encephalopathy occurring in <7 days.

Acute - jaundice with encephalopathy occurring from 1 to 4 weeks of onset

Subacute - jaundice with encephalopathy occurring within 4-12 weeks of onset

Acute-on-chronic- acute deterioration (decompensation) in patients with chronic liver failure

Question 6

Name 2 main causes of liver failure and list some less common causes.

Answer 6

Viral - hepatitis A, C, D, E, “non A-E hepatitis”

Drugs - paracetamol overdose, idiosyncratic drug reactions (e.g. anti-TB therapy_

Less commonly - autoimmune hepatitis, Budd-Chiari syndrome, pregnancy-related malignancy (e.g. lymphoma), haemochromatosis, mushroom poisioning (Amanita phalloides), Wilson’s disease

Question 7

What is the pathogenesis of acute liver failure?

Answer 7

Jaundice - decreased secretion of conjugated bilirubin

Encephalopathy - increased delivery of gut-derived products into the systemic circulation and brain from reduced extraction of nitrogenous products by liver and portal systemic shunting . Ammonia may play a part.

Coagulopathy - decreased synthesis of clotting factors, decreased platelets (hypersplenism if chronic portal hypertension) or platelet functional abnormalities associated with jaundice of renal failure

Question 8

What is the most common aetiology of liver failure?

Answer 8

Paracetamol overdose accounts for 50% of acute liver failure in the UK

Question 9

What are the symptoms of liver failure?

Answer 9

• May be asymptomatic
• Fever
• Nausea
• Jaundice

Question 10

What are the signs of liver failure on examination?

Answer 10

• Jaundice, encephalopathy, liver asterixis (negative myoclonus), fetor hepaticus (smell of “pear drops”)
• Ascites and splenomegaly (less common if acute/hyperacute)
• Bruising or bleeding from puncture sites of GI tract

_Look for secondary cause_s: e.g. bronze skin colour, Kayser-Fleischer rings

Pyrexia may reflect inflection or liver necrosis

Question 11

What investigations would you do to identify the cause of liver failure?

Answer 11

• Viral serology
• Paracetamol levels
• Autoantibodies (e.g. ASM, LKM antibody, immunoglobulins)
• Ferritin
• Caeruloplasmin
• Urinary copper (low and high respectively in Wilson’s)

Question 12

What investigations should you do for liver failure?

Answer 12

Bloods:

• FBC - low Hb if GI bleed, high WCC in infection
• U&E - hepatorenal failure
• Glucose
• LFT -high bil, transaminases, Alkphos, GGT and low albumin,
• ESR/CRP (inflammatory markers)
• Coagulation screen (high PT and INR)
• ABG (to determine pH)
• Group and save

Imaging:

• US liver, CT scan to image liver
• Doppler of hepatic and portal veins - exclude Budd Chiaru syndrome
• EEG - monitor encephalopathy

Invasive:

• Ascitic fluid tap - MC&S, biochemistry (glucose, protein), cytology, >250neutrophils/mm3 indicates SBP

Question 13

Why would you do a Doppler of hepatic/portal veins in liver failure?

Answer 13

Doppler of hepatic and portal veins - exclude Budd Chiaru syndrome

Question 14

How do you treat paracetamol overdose?

Answer 14

N-acetylcysteine

Question 15

How do you manage liver failure (and its complications)?

Answer 15

Resuscitation - ABCDE, ITU care and specialist care unit support

Treatment/prevention of complications - invasive respiratory and cardiovascular support often required

• Monitor - vital signs, pH, creatinine, urine output, encephalopathy
• Encephalopathy - lactulose and phosphate enemas
• Antibiotic and antifungal prophylaxis
• Hypoglycaemia treatment
• Coagulopathy treatment - IV Vit K, FFP, platelet infusions if required
• Gastric mucosa protection - PPI or sulcralfate
• Avoid - sedatives and drugs metabolised by liver
• Cerebral oedema - nurse patient at 30 degrees C, lower intracranial pressure by IV mannitol, hyperventilate

Question 16

What criteria is used when assessing patient with liver failure for surgical intervention?

Answer 16

Kings College Hospital criteria for liver transplantation:

If due to paracetamol overdose:

• arterial pH <7.3 or
• PT>100s, creatinine <300 and severe encephalopathy

For other causes 3 out of 5 of:

• age <10 or >40 years
• bilirubin >300 microM
• caused by non-A, non-E viral hepatitis or drugs
• interval from jaundice onset to encephalopathy >7 days or
• PT>100s

Question 17

What are the complications of liver failure?

Answer 17

• Infection
• Coagulopathy
• Hypoglycaemia
• Electrolyte disturbance
• Acid-base and cardiovascular system
• Hepatorenal syndrome (concurrent hepatic and renal failure)
• Cerebral oedema
• Raised intracranial pressure
• Respiratory failure

Question 18

What is the prognosis with liver failure?

Answer 18

Depends on severity and aetiology of the liver failure

Childs-Pugh score can be calculated to show surgical mortality

Question 19

Which scoring system is used to assess prognosis of liver disease and required strength of treatment/liver transplantation necessity?

Answer 19

The Child-Pugh score is a system for assessing the prognosis — including the required strength of treatment and necessity of liver transplant — of chronic liver disease, primarily cirrhosis.

Question 20

How is the value of the PT significant in liver failure?

Answer 20

Normal PT is about 12-14 seconds

General rule: if the PT (s) is higher than the number of hours since the overdose, the patient should be transferred to a liver unit for a transplant

Question 21

What is the use of lactulose in liver failure?

Answer 21

Lactulose works to inhibit production of ammonia in the intestine

Question 22

What are the grades of hepatic encephalopathy?

Answer 22

Grading of hepatic encephalopathy

• Grade I: Irritability
• Grade II: Confusion, inappropriate behaviour
• Grade III: Incoherent, restless
• Grade IV: Coma