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WERNICKE’S ENCEPHALOPATHY |
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Alcohol accounts for an estimated 100,000 deaths/year in the U.S.
Wernicke’s encephalopathy is a condition most
commonly seen in chronic alcoholics in the U.S. This condition reflects the
effect of severe and sustained thiamine depletion
in the presence of continued calorie intake. Wernicke's
is a medical emergency. If not recognized and treated promptly, it
can lead to permanent neurologic disability or death.
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Thiamine is required for oxidative carboxylation of pyruvate and a-ketoglutarate
which are required for energy metabolism of most cells, especially nervous
tissue cells. The dehydrogenase reactions require thiamine in order to produce
ATP. |
Nervous Tissue Physiological Changes:
Axonal demyelination
Neuronal loss
Glial proliferation
Petechial pericapillary hemorrhages |
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Above: Pathologic specimens in Wernicke's encephalopathy. Note the hemorrhagic
lesions in the medial thalamus adjacent ot the third ventricle (left) and in the
mamillary bodies (right). |
The oculomotor, vestibular, medullary autonomic nuclei,
and the brainstem reticular formation are the most affected. At
higher levels, the mamillary bodies, the
mediodorsal thalamic nuclei, and scattered cortical regions, including
hippocampus are also affected.
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Clinical Presentation
Classic Triad:
• Mental State Changes
Confused to stupor to coma
• Ataxia
• Ophthalmoplegia
Partial or complete external opthalmoplegia
Nystagmus
Pupils may only sometimes be affected
Any motor cranial nerve can be partially affected
Other Clinic Findings That May Be Present:
Tachycardia
Orthostatic hypotension
Hypothermia
Seizures (including status) |
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Above: MRI images; (Left) Axial flair,
(Middle) Axial T1 weighted, (Right) Axial T1 weighted with gadolinium in a
patient with Wernicke's. Note the enhancement of the mamillary bodies on the
post-gadolinium scan and the prominent signal changes in the hypothalamus and
mamillary bodies on the flair image.
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Treatment
• Administer thiamine,
100 mg parenterally, upon suspicion of
diagnosis, followed by replenishment of blood volume and electrolytes. The
response to thiamine administration is diagnostic. The opthalmoplegia should
begin to improve within a matter of hours to a day.
• Glucose replenishment should not precede
thiamine because it may actually precipitate acute worsening of this condition
• Patients should also be observed for any
withdrawal seizures or delirium tremens |
