Wernicke's encephalopathy (N)

Question 1

Define Wernicke’s encephalopathy.

Answer 1

Acute (reversible) neurological emergency resulting from thiamine (vitamin B1) deficiency

Question 2

What are the causes of Wernicke’s encephalopathy? (3)

Answer 2

• chronic heavy alcohol consumption - most common
• inadequate intake or malabsorption of thiamine (EDs, malnutrition, prolonged vomiting etc)
• bariatric surgery predisposes to thiamine malabsorption

Question 3

What is the most common cause of Wernicke’s encephalopathy?

Answer 3

Chronic alcohol consumption

Question 4

What demographic does Wernicke’s encephalopathy happen most commonly in?

Answer 4

M>F - due to increased frequency of alcoholism in men

Question 5

How does Wernicke’s encephalopathy typically present?

Answer 5

Varied neurological manifestations, typically involving mental status changes, and gait and oculomotor dysfunction

Question 6

What are the clinical features of Wernicke’s encephalopathy? (5)

Answer 6

• confusion + mental status changes
• oculomotor signs - ophthalmoplegia (weakness/paralysis of eye muscles), nystagmus, diplopia, ptosis
• gait ataxia - wide-based, small steps
• mental slowing, impaired concentration and apathy
• memory loss

Question 7

What oculomotor signs are seen in Wernicke’s encephalopathy? (4)

Answer 7

• ophthalmoplegia - weakness/paralysis of eye muscles:
• nystagmus
• diplopia
• ptosis

Question 8

What might you find on examination of Wernicke’s encephalopathy (rarer findings)? (5)

Answer 8

• patient usually mentally alert with vocabulary, comprehension, motor skills, social habits and naming ability maintained
• reflexes may be decreased
• papilloedema, retinal haemorrhages
• hypothermia
• tachycardia / hypotension

Question 9

What is the classic triad of Wernicke’s encephalopathy?

Answer 9

• mental status changes
• ophthalmoplegia (nystagmus, diplopia, ptosis, impaired VOR)
• gait dysfunction

Question 10

What is Wernicke’s COAT?

Answer 10

• Confusion
• Ophthalmoplegia
• Ataxia
• Thiamine IV administration

Question 11

What is it called when Wernicke’s encephalopathy progresses into a chronic, irreversible condition?

Answer 11

Korsakoff’s Psychosis

(Wernicke’s encephalopathy = acute and reversible)

Question 12

What are the main features of Korsakoff’s Psychosis?

Answer 12

CART:

• Confabulation (making things up)
• Anterograde + Retrograde Amnesia
• Temper (altered)

(CART for Korsakoff’s, COAT for Wernicke’s encephalopathy)

Question 13

What is the difference between Wernicke’s encephalopathy and Korsakoff’s psychosis?

Answer 13

• Wernicke’s encephalopathy - acute, reversible, COAT
• Korsakoff’s psychosis - chronic, irreversible, CART (confabulation and amnesia added)

Question 14

What are the risk factors for Wernicke’s encephalopathy? (5)

Answer 14

• alcohol-use disorder
• HIV infection and AIDS
• cancer and treatment with chemotherapeutic agents
• malnutrition
• Hx of GI surgery

Question 15

How is Wernicke’s encephalopathy usually diagnosed?

Answer 15

Clinical diagnosis

Question 16

What are some other investigations done for Wernicke’s encephalopathy? (4)

Answer 16

• therapeutic trial of parenteral thiamine - clinical response within hours/days
• bloods - decreased thiamine
• MRI - atrophy of mamillary bodies
• screening tool for alcohol withdrawal = Clinical Institute Withdrawal Assessment for Alcohol (CIWA)

Question 17

What electrolyte may be low in Wernicke’s encephalopathy?

Answer 17

Magnesium - deficiency common in alcohol misuse, and it impairs thiamine therapeutics

Question 18

What might MRI show in Wernicke’s encephalopathy?

Answer 18

Atrophy of mamillary bodies

Question 19

What are some differential diagnoses for Wernicke’s encephalopathy? (5)

Answer 19

• alcohol intoxication
• alcohol withdrawal - delirium tremens = tachycardia, hypertension, agitation, diaphoresis, mydriasis, hallucinations, seizures
• viral encephalitis
• toxic encephalopathies - phenytoin, aspirin, carbamazepine, BZs
• metabolic encephalopathies (hepatic and uraemic)

Question 20

What is the first-line treatment for Wernicke’s encephalopathy?

Answer 20

Immediate IV thiamine (IV Pabrinex) + vitamin/mineral supplementation

Pabrinex (yellow-coloured fluid) contains vitamins B and C

Question 21

How do we manage moderate/high suspicion Wernicke’s encephalopathy?

Answer 21

IV thiamine (Pabrinex) + magnesium sulfate + multivitamins

Question 22

How do we manage those at high risk of Wernicke’s encephalopathy (but do not have it yet)?

Answer 22

Supplement diet with thiamine + vitamin/mineral supplementation

Question 23

How do we manage chronic Wernicke’s encephalopathy?

Answer 23

Dietary supplementation with thiamine (oral or IM)

Question 24

When should thiamine be administered (Wernicke’s encephalopathy)?

Answer 24

Before carbohydrate administration

Question 25

What do we give if delirium tremens and hallucinations (Wernicke’s encephalopathy)?

Answer 25

Benzodiazepine (Chlordiazepoxide)

Question 26

What are some complications of Wernicke’s encephalopathy? (5)

Answer 26

• ataxia + ophthalmoplegia
• Korsakoff’s psychosis (confabulations, anaemia)
• hearing loss
• seizures
• spastic paraparesis

Question 27

Describe the prognosis of Wernicke’s encephalopathy.

Answer 27

If not recognised and treated early, can lead to permanent brain injury and death