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Wernicke’s Encephalopathy AMITESHWAR SINGH

INTERN, KMC MANIPAL.

Dr Carl WernickeA Polish neurologist, who

described this neuropsychiatric

syndrome in 1881 as a triad of acute mental

confusion, ataxia, and ophthalmoplegia.

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3Etiopathogenesis Deficiency of vitamin B1 (thiamine) An essential coenzyme in several

biochemical pathways in the brain, Krebs cycle and the pentose phosphate

pathway α-ketoglutarate dehydrogenase, pyruvate

dehydrogenase, and transketolase. Mainly involved in the glucose

metabolism and cerebral energy utilization

Inhibition of metabolism in brain regions with higher metabolic

demands and high thiamine turnover.

4THIAMINE DEFICIENCY

Failure of thiamine-dependent cellular systems

Energy production drops, and neuronal damage ensues

BRAIN TISSUE INJURY

Reduced production of

succinate

Failure of GABA metabolism

5Causes Chronic alcoholism – Malnutrition –

reduced thiamine uptake and utilization Prolonged starvation Hyperemesis Gravidarum Bariatric Surgery (Bariatric BeriBeri) Malabsorption Syndromes Infants on formula diet deficient in

thiamine

Epidemiology

The incidence can be as high as 12.5% in a population of alcoholics.

The prevalence approximately 2%.

The male-to-female ratio is 1.7 : 1Average age at onset is 50 years.

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History

The classical triad of symptoms – only 1/3rd of cases

Evidence of long-term alcohol abuse or malnutrition 

Other symptoms could include memory disturbance, hypothermia with hypotension, and delirium tremens.

Special clinical scenarios as previously mentioned

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8Physical examination

Ocular abnormalities – nystagmus , bilateral lateral rectus palsies, conjugate gaze palsies, sluggish pupils, ptosis, and anisocoria

Encephalopathy – global confusional state, disinterest, inattentiveness, or agitation; Coma is rare. 

Gait ataxia – cerebellar damage, and vestibular paresis

Peripheral neuropathy – foot drop, and decreased proprioception

9Differential Diagnosis

Psychosis Normal pressure hydrocephalus Cerebrovascular accident Chronic hypoxia Closed-head injury Hepatic encephalopathy Postictal state

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Work-Up CBC – R/o severe anemias and leukemias

as causes of altered mental status Blood glucose levels - Exclude

hypoglycemia/ hyperglycemia O2 Saturation and ABG - Exclude

hypoxia/ hypercarbia; Metabolic Acidosis may be+

Toxic drug screening - Excludes some causes of drug-induced altered mental status.

Lumbar puncture (LP) - Exclude CNS infections, if indicated

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CT/MRI – exclude ICSOLs etc.No particular Changes in acute

presentation Chronic encephalopathy - excessive

mamillary body and cerebellar shrinkage 

Erythrocyte transketolase activity assay, Thiamine assay – very specific tests – not widely available – reserved for diagnostic dilemmas

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Treatment Emergency department care – Parenteral

thiamine –Requirement in chronic alcoholics may be as high as 500mg single dose or multiple daily doses.

Never start on Dextrose Parenteral magnesium sulfate as thiamine therapy

ineffective in presence of hypomagnesemia In-Patient care – Watch for complications –

Korsakoff psychosis – Alcohol withdrawal – Congestive heart failure – Lactic acidosis

Out-Patient Care – Thiamine 100 mg PO daily, start alcohol cessation program, Advise on importance of balanced diet.

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Wernicke-Korsakoff Syndrome

85% of the survivors of the acute phase of Wernicke encephalopathy who remain untreated go on to develop Wernicke-Korsakoff syndrome.

It manifests with memory loss and confabulation.

About 20% eventually recover completely during long-term follow-up care.

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Conclusion

Wernicke encephalopathy must be considered as a medical emergency, as it is associated with significant morbidity and mortality.

Because the condition is potentially reversible, early diagnosis is important.

The diagnosis is clinical and is mainly supported by the dramatic improvement of neurological signs on parenteral thiamine therapy.