Hepatic Encephalopathy

Question 1

A build up do what causes hepatic encephalopathy?
What are the 2 reasons in builds up?

Answer 1

Ammonia

1. Functional liver impairment prevents liver cells metabolising the ammonia into harmless waste products
2. Collateral vessels between the portal and systemic circulation mean that ammonia bypasses the liver and directly enters the systemic system

Question 2

How is ammonia produced?

Answer 2

Produced by intestinal bacteria when they breakdown proteins

Question 3

What does hepatic encephalopathy present with. Acutely? Chronically?

Answer 3

Acute
- reduced consciousness
- confusion
Chronically
- changes to personality, memory and mood

Question 4

What factors worsen hepatic encephalopathy? (7)

Answer 4

• Constipation
• Dehydration
• Electrolyte disturbance
• Infection
• Gastrointestinal bleeding
• High protein diet
• Medications (particularly sedative medications)

Question 5

What is the management of hepatic encephalopathy? (3)

Answer 5

○ Lactulose (aiming for 2-3 soft stools daily)
○ Antibiotics (e.g., rifaximin) to reduce the number of intestinal bacteria producing ammonia
○ Nutritional support (nasogastric feeding may be required)

Question 6

How does lactulose work in hepatic encephalopathy? (3)

Answer 6

Works to reduce ammonia
§ Speeds up transit time and reduces constipation (the laxative effect clearing the ammonia before it is absorbed)
§ Promotes bacterial uptake of ammonia to be used for protein synthesis
§ Changes the pH of the contents of the intestine to become more acidic, killing ammonia-producing bacteria

Question 7

What antibiotic is first line in hepatic encephalopathy? Why?

Answer 7

Rifaximin
Poorly absorbed and stays in the GI tract