Wernicke's Encephalopathy

Question 1

What is Wernicke’s encephalopathy?

Answer 1

The presence of neurological symptoms caused by biochemical lesions of the central nervous system following exhaustion of vitamin B (particularly thiamine/B1) reserves
(Acute, reversible condition) manifesting in a triad of specific clinical symptoms: ataxia, confusion, and ocular abnormalities.

Question 2

What causes Wernicke’s encephalopathy?

Answer 2

1. Main cause is CHRONIC ALCOHOL CONSUMPTION which results in thiamine deficiency by causing:
   - Inadequate nutritional thiamine intake
   - Decreased thiamine absorption
   - Impaired thiamine utilisation by cells
2. Other causes of thiamine deficiency:
   - Eating disorders
   - Malnutrition
   - Prolonged vomiting e.g. with chemotherapy
   - GI malignancy
   - Chronic subdural haematoma
   - AIDS
   - Hyperemesis gravidarum
   - Thyrotoxicosis
3. Thiamine deficiency results in abnormal cellular function in the cerebral cortex, hypothalamus and cerebellum

Question 3

Summarise the epidemiology of Wernicke’s encephalopathy

Answer 3

Alcohol-related brain damage accounts for 10-24% of all dementia
Prevalence rates are higher in areas of socio-economic deprivation
Higher prevalence in 50-60 year olds

Question 4

What are the presenting symptoms of Wernicke’s encephalopathy

Answer 4

• Vision changes: diplopia, eye movement abnormalities, ptosis
• Loss of muscle coordination: unsteady gait
• Loss of memory
• Inability to form new memories
• Hallucinations

Question 5

What signs of Wernicke’s encephalopathy can be found on physical examination

Answer 5

1. Wernicke’s is classically defined by a triad of signs:
   - Confusion
   - Ophthalmoplegia (nystagmus, lateral rectus or conjugate gaze palsies)
   - Ataxia (wide based gait)
2. The patient is usually mentally alert with vocabulary, comprehension, motor skills, social habits and naming ability maintained
3. Some show signs suggestive of polyneuropathy (simultaneous malfunction of many peripheral nerves throughout the body.)
4. Reflexes may be decreased
5. Abnormal gait and coordination
6. Eye abnormalities on movement: nystagmus, bilateral lateral rectus palsy, conjugate gaze palsy
7. Low temperature
8. Rapid pulse
9. Some may be cachectic
10. NOTE: Korsakoff’s Psychosis occurs when the condition deteriorates further, leading to the additional symptoms of:
    - Amnesia
    - Confabulation (patient generates a false memory without the intention of deceit)

Question 6

What investigations are used to diagnose/ monitor Wernicke’s encephalopathy?

Answer 6

1. Usually a clinical diagnosis
2. Decreased blood thiamine levels
3. MRI → atrophy of mamillary bodies
4. Screening tool for alcohol withdrawal = Clinical Institute Withdrawal Assessment for Alcohol (CIWA)

Question 7

How is Wernicke’s encephalopathy managed?

Answer 7

1. Immediate IV Thiamine (Pabrinex) (if patient at risk of Wernicke Encephalopathy, supplement diet with thiamine)
2. Delirium Tremens (if hallucinations) → Tx with a benzodiazepine (chlordiazepoxide).
3. Abstinence from Alcohol

Question 8

What complications are associated with Wernicke’s encephalopathy?

Answer 8

• Ataxia
• Hearing loss
• Seizures
• Failure to treat leads to Wernicke-Korsakoff syndrome