Wernicke's Encephelopathy and Korsakoff's Syndrome

Contents

Wernicke’s Encephalopathy

This is a disorder that occurs as a result of inadequate levels of vitamin B1 (thiamine) in the body.

It results in:

Ataxia
Ophthalmoplegia
- Nystagmus – may be horizontal and vertical
- Conjugate gaze problems
Confusion
Short Term Memory Loss

In some patients it may also cause reduced consciousness, hypotension and hypothermia

Associated with alcohol addiction in the vast majority of cases
- Alcohol impairs the GI absorption and hepatic storage of thiamine
- Alcoholic patients also tend to be malnourished, and thus have a low thiamine intake
May also be due to eating disorders, prolonged vomiting, GI malignancy, amphetamine addiction or Crohn’s disease

Results from prolonged thiamine deficiency alongside continued carbohydrate ingestion
There is degradation of the thalamic nuclei, brainstem nuclei and cerebellum and other structures around the 3^rd and 4^th ventricles, and the aqueduct.
Changes are symmetrical

Is clinical. Look for the ‘tried’ of:

Many cases are missed and left untreated.

Treatment should be URGENT to prevent the irreversible Korsakoff’s syndrome (below)
Give high dose IV thiamine (e.g. 500mg Thiamine TDS, or Pabrinex – 2-3 ampules IV every 8 hours over 10 minutes for 3-5 days)
- Then, continue with oral thiamine
- Risk of anaphylaxis (rare)
WARNING – be wary of hypoglycaemia. if this also exists, then give thiamine before glucose as glucose can precipitate the symptoms of Wernicke’s in susceptible patients (due to the joint pathology of thiamine deficiency + carbohydrate ingestion).
If untreated:
- Death occurs in 20%
- Korsakoff’s syndrome occurs in 85% of patients. When both occurr together, it is known as Wernicke-Korsakoff syndrome

This is a complication of untreated Wernicke’s encephalopathy, although it can occur without prior symptoms of Wernicke’s

Most commonly thiamine deficiency secondary to alcohol abuse
Can also be due to subarachnoid haemorrhage and other strokes and brain haemorrhages, as well as brain tumours in the thalamic region.

Amnesia – both antero and retrograde to varying degrees
- Anterograde memory loss – inability to acquire new memories
- Retrograde Memory loss – loss of old memories
Loss of orientation in time and space
Apathy and little response to events in the world around them
Mild euphoria
Confabulation– making up stories! These can often be very convincing, although usually have no basis in fact

In thiamine deficiency, Korskoff’s is considered irreversible, however:
- 20% of patients will fully recover, but
- 25% of patients will require prolonged institutional care
- Symptoms may improve up to 14 months after onset
- Treatment is with thimaine and adequate hydration
In Korsakoff’s due to stroke or bleed, the prognosis is good, and symptoms will usually resolve after treatment of the underlying cause.