Wernicke's Encephalopathy Flashcards
Define
the presence of neurological symptoms caused by biochemical lesions of the central nervous system following exhaustion of vitamin B (particularly thiamine) reserves.
Causes
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
Other conditions that cause thiamine deficiency:
- Chronic subdural haematoma
- AIDS
- Hyperemesis gravidarum
- Thyrotoxicosis
Thiamine deficiency results in abnormal cellular function in the cerebral cortex, hypothalamus and cerebellum
Epidemiology
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
Symptoms
Vision changes: diplopia, eye movement abnormalities, ptosis
Loss of muscle coordination: unsteady gait
Loss of memory
Inability to form new memories
Hallucinations
Signs
Wernicke’s is classically defined by a triad of signs:
- Confusion
- Ophthalmoplegia
- Ataxia
The patient is usually mentally alert with vocabulary, comprehension, motor skills, social habits and naming ability maintained
Some show signs suggestive of polyneuropathy
Reflexes may be decreased
Abnormal gait and coordination
Eye abnormalities on movement: nystagmus, bilateral lateral rectus palsy, conjugate gaze palsy
Low temperature
Rapid pulse
Some may be cachectic
NOTE: Korsakoff’s Psychosis occurs when the condition deteriorates further, leading to the additional symptoms of:
- Amnesia
- Confabulation
Investigations
Diagnosis is mainly based on history and examination
Possible useful tests:
- FBC (high MCV is a common feature amongst alcoholics)
- U&Es (exclude metabolic imbalances as a cause of confusion)
- LFTs
- Glucose
- ABG (hypercapnia and hypoxia can cause confusion)
- Serum thiamine
CT head scan may be useful
