Wernicke’s encephalopathy

AKA Wernicke-Korsakoff encephalopathy (not to be confused with Korsakoff’s syndrome or Korsakoff’s psychosis).

Classic triad: encephalopathy (consisting of global confusion), ophthalmoplegia, and ataxia (NB: all 3 are present in only 10–33% of cases).

Due to thiamine deficiency. Body stores of thiamine are adequate only for up to ≈ 18 days.

May be seen in:

1. a certain susceptible subset of thiamine deficient alcoholics. Thiamine deficiency here is due to a combination of inadequate intake, reduced absorption, decreased hepatic storage, and impaired utilization

2. hyperemesis (as in some pregnancies)

3. starvation: including anorexia nervosa, rapid weight loss

4. gastroplication (bariatric surgery)

5. hemodialysis

6. cancers

7. AIDS

8. prolonged IV hyperalimentation

Oculomotor abnormalities occur in 96% and include nystagmus (horizontal > vertical), lateral rectus palsy, conjugate-gaze palsies.

Gait ataxia is seen in 87% and results from a combination of polyneuropathy, cerebellar dysfunction, and vestibular impairment.

Systemic symptoms may include: vomiting, fever.

MRI: May show high signal in T2 weighted image and FLAIR images in the paraventricular (medial) thalamus, the floor of the 4th ventricle, and periaqueductal gray of the midbrain. These changes may resolve with treatment ¹⁾.

Atrophy of the mammillary bodies may also be seen. Normal MRI does not R/O the diagnosis.

Although as little as 2 mg of thiamine may be enough to reverse symptoms, the dose of thiamine required to prevent or treat WE in most alcoholic patients may be as high as greater than 500 mg given once or, preferably, 2 or 3 times daily parenterally, intravenous is preferred to intramuscular administration.

Wernicke’s encephalopathy (WE) is a medical emergency. When WE are suspected, 100 mg thiamine should be given IM or IV (the oral route is unreliable) daily for 5 days.

✖ IV glucose can precipitate acute WE in thiamine deficient patients, ∴ give thiamine before glucose.

Thiamine administration improves eye findings within hours to days; ataxia and confusion improve in days to weeks. Many patients that survive are left with horizontal nystagmus, ataxia, and 80% have Korsakoff’s syndrome (AKA Korsakoff’s psychosis), a disabling memory disturbance involving retrograde and anterograde amnesia.