2+ Hepatic Encephalopathy

Question 1

What is hepatic encephalopathy?

Answer 1

Brain dysfunction caused by liver insufficiency and/or portosystemic shunt. It manifests as a wide spectrum of neurological or psychiatric abnormalities from subclinical alterations to coma

Question 2

What is the aetiology of hepatic encephalopathy?

Answer 2

Likely reflects a combination of metabolic encephalopathy, brain atrophy and/or cerebral oedema

Ammonia has been implicated as a neurotoxin in the pathogenesis of the disease

Precipitating factors: GIT bleeding, infection, sedatives/opiates, hypokalaemia, alkalosis, increased protein intake and constipation

Question 3

What is the pathophysiology of hepatic encephalopathy?

Answer 3

The gut is the primary source of ammonia absorbed into the circulation through the portal venous system
- Ammonia is a byproduct of the bacterial catabolism of nitrogenous sources such as ingested protein
- Impaired liver function = impaired ammonia clearance
- Portosystemic shunts from cirrhosis = reduce ammonia clearance further

Hyperammonemia may alter cerebral concentrations of amino acids and thus neurotransmitter synthesis

Question 4

What is the clinical presentation of hepatic encephalopthy?

Answer 4

• Mood disturbances: euphoria or depression
• Sleep disturbances: insomnia or hypersomnia
• Motor disturbances: ataxia, EPS (muscle rigidity, bradykinesia, hypokinesia, slowed speech, parkinsonian-like-tremor)
• Advanced neurological deficits: confusion, nystagmus, hyperreflexia, clonus
• Signs of chronic liver disease
• Risk factors for chronic liver disease

Question 5

What investigations do you do when someone has hepatic encephalopathy?

Answer 5

Ix to identify the trigger:
- UA
- Urine MCS
- Blood culture
- Urine toxin screen: opioids/sedatives
- UECs: hypokalaemia, urea raised from GIT bleeding
- VBG: metabolic alkalosis
- FBC: leucocytosis from infection

General Ix:
- Head CT in all patients with first episode of HE

Question 6

How do you manage hepatic encephalopathy?

Answer 6

1. Supportive + reversal of precipitating factors
2. Lactulose: prophylaxis in all patients with cirrhosis
3. Rifaximin: prevents the recurrence of HE and is a recommended add on to lactulose in patients with episodic HE

Question 7

What are the complications of hepatic encephalopathy?

Answer 7

Falls
Persistent cognitive impairment
Cerebral oedema
Neurological deficits