WERNICKE'S ENCEPHALOPATHY

WERNICKE'S ENCEPHALOPATHY

Introduction:

Acute clinical syndrome due to thiamine deficiency (vitamin B1)

- mainly seen in those who abuse alcohol

- requires high degree of suspicion in all patients (especially those at risk)

Clinical Presentation:

Triad of:

1) Confusion

- often quiet hypokinetic delirium w/ significant spatial & temporal disorientation

(give wrong year, off by decades)

- apathetic & inattentive, little spontaneous speech

2) Ataxia

- primarily of stance & gait (not usually involving speech & limbs)

3) Ophthalmoplegia / abnormal eye movements

- especially nystagmus (incl. vertical) and/or bilateral abducens palsy or conjugate gaze palsy

- absent caloric responses

* may have associated polyneuropathy from alcoholism & thiamine deficiency

(together = psychosis polyneuritica) *

NB: not all of these features present in autopsy-confirmed cases

- complete triad may only occur in 10-20% of cases

- suspect this diagnosis and give thiamine in any patient with alcohol abuse who presents with confusion, ataxia or eye movement abnormality (as well as if any of risk factors below)

Etiology: Thiamine Deficiency

1) Alcohol Abuse

2) Malnutrition (of other causes)

3) Parenteral Nutrition

4) Hyperemesis

5) GI Malabsorption disorders

6) AIDS

7) Dialysis

Imaging & Neuropathology:

Regions affected:

- Thalamus, hypothalamus, mamillary bodies, and PAG (periaqueductal gray)

(includes all paraventricular regions incl. walls of third & fourth ventricles)

- punctate hemorrhages w/ focal necrosis, gliosis, demyelination & neuronal loss

- ? due to spread of excitotoxin via intraventricular CSF flow

- may see MRI changes in these areas on FLAIR, T2 or T1 w/ contrast

- reports of DWI high signal also in these areas

These abnormalities can resolve with Rx

- if permanent damage occurs with progression to Korsakoff's amnestic sydnrome, then can see atrophy in same areas

- much higher rate of pathologic changes at autopsy in alcoholics than diagnosed clinically

(1-2% in general population even)

Management:

Parenteral thiamine (eg 100 mg IV or IM) immediately and daily x total of 3-5 doses

- continue oral or enteral B vitamin complex thereafter

(do not use oral treatment acutely as often poor absorption)

- do NOT give glucose-containing IV solutions before thiamine (ie. D5W) as this can precipitate Wernicke's (thiamine utilized in glucose metabolism)

Outcome:

Reversible only if treated early

- symptoms may improve in days to weeks (oculomotor resolves even in hours, gait more slowly)

If untreated (or even with treatment) can lead to permanent CNS damage

(continuum of same pathologic process)

- especially involving dorsal median nucleus of thalamus +/- mamillary bodies

- predominantly an amnestic syndrome characterized by lack of memory formation and compensatory confabulation in an alert patient

= Korsakoff syndrome

(essentially irreversible at this stage)

- 20% or more may present with amnestic syndrome without obvious confusional episode

NB: not a true dementia as no aphasia / apraxia or other cognitive dysfunction

(isolated memory impairment without insight)

References:

Charness ME, Simon RP, Greenberg DA. Ethanol and the nervous system. N Engl J Med 1989; 321: 442-54.

Zubaran C, Fernandes JG, Rodnight R. Wernicke-Korsakoff syndrome. Postgrad Med J 1997; 73: 27-31.

Last update: January 10, 2003

Reviewed by: Pending review

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