Hepatic encephalopathy

Question 1

Risk factors

Answer 1

Hypovolaemia
GI bleed
Constipation
Excessive protein intake
Hypokalaemia
Hyponatraemia
Metabolic alkalosis
Hypoxia

Question 2

Pathophysiology

Answer 2

Brain injury due to toxic metabolites not removed by liver due to liver dysfunction
Accumulation of toxic metabolites (e.g. ammonia) by product of nitrogen metabolism
Ammonia detoxification is astrocytes -> glutamine accumulation -> osmotic stress -> swelling
Other injuries (e.g. alkalosis, metabolic abnormalities, medications, bleeding infection) = hepatic encephalopathy

Question 3

Signs and symptoms

Answer 3

Confusion
Stupor
Poor concentration
Coma
Asterixis
Rigidity
Hyperreflexia

Question 4

West haven criteria

Answer 4

Grade 1: Trivial lack of awareness. Impaired attention span. Altered sleep, euphoria or depression. Mild asterixis may be present.
Grade 2: Lethargy or apathy. Disorientation. Inappropriate behavior. Slurred speech. Asterixis.
Grade 3: Gross disorientation. Bizarre behavior. Semi-stupor. Asterixis absent.
Grade 4: Coma (unresponsive to verbal or noxious stimuli)

Question 5

Diagnosis

Answer 5

T1 weighted MRI
Bloods = increased ammonia

Question 6

Treatment

Answer 6

FIRST LINE = Lactulose
SECOND LINE = RIFAXIMIN
- kill bowel flora that produce ammonia