Wernicke’s Encephalopathy

Wernicke’s Encephalopathy

Definition: Thiamine deficiency with a classical triad of confusion, ataxia, and ophthalmoplegia.

Aetiology/ risk factors:

Image result for vitamin b1-Thiamine (Vitamin B1) deficiency

-inadequate dietary intake

-reduced GI absorption

-impaired utilisation

= focal areas of brain damage, including periaqueductal punctate haemorrhages

-Often seen in chronic alcoholism

Also: eating disorders, malnutrition, prolonged vomiting e.g. with chemo, GI malignancy, extreme morning sickness (Hyperemesis gravidarum)

Epidemiology:

-12.5% prevalence in patients with alcohol dependence

Symptoms:

-confusion/delirium, disorientation, apathy

-memory disturbance

-diplopia (double vision)

Image result for wernicke's encephalopathy ataxiaSigns:

ophthalmoplegia = nystagmus, lateral rectus (inability to abduct eye) or conjugate gaze palsies (inability to move both eyes in a single direction), internuclear ophthalmoplegia

-gait ataxia = wide-based gait

-hypotension, hypothermia, reduced consciousness

Investigations:

-Diagnosis primarily clinical and based on response to thiamine

Red cell transketolase activity decreased (rarely done)

Management:

Urgent replacement

-IV Pabrinex- high potency vitamins C (ascorbic acid), B1 (thiamine), B2 (riboflavin), B3 (nicotinamide) and B6 (pyridoxine).

-2 pairs of high potency ampoules (IV/IM/8h) over 30 min for 2 days, then 1 pair daily for a further 5 days.

-oral supplementation until no longer at risk (100mg/d)

-If there is also hypoglycaemia, make sure that thiamine is given before glucose.

-Correct any magnesium deficiency (co-factor for thiamine)

-Advice and support for alcohol cessation

Complications:

-Irreversible Korsakoff’s syndrome (a.k.a Korsakoff’s psychosis) if not treated urgently

= reduced ability to acquire new memories (anterograde amnesia)

= confabulation (invented memory owing to retrograde amnesia)

= lack of insight, apathy

-Hearing loss

-Seizures

-Spastic paraparesis

Prognosis:

-reversible with prompt treatment

-untreated = 20% death, 85% Korsakoff’s psychosis (1/4 of these will need institutional care)

References: Cheese & Onion, Rapid Medicine, BMJ Best Practice

 

 

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