Wernicke's Encephalopathy

Question 1

Define Wernicke’s Encephalopathy

Answer 1

A neurological emergency resulting from thiamine deficiency, typically involving mental status changes and gait and oculomotor dysfunction

Question 2

Aetiology of Wernicke’s Encephalopathy

Answer 2

Acute or sub-acute deficiency of thiamine

Decreased intake, relative deficiency due to increased demand or malabsorption

Question 3

Risk Factors for Wernicke’s Encephalopathy

Answer 3

Alcohol dependence
AIDS
Cancer treatment with chemotherapeutic agents 
Malnutrition
Malignancy 
gastric bypass surgery 
Haemodialysis 
Hyperemesis gravidarum

Question 4

Symptoms of Wernicke’s Encephalopathy

Answer 4

Mental slowing, impaired concentration, apathy
Frank confusion
Mild irritability
Delirium
Coma
Hearing loss, seizures, spastic paraparesis

Typical patient = alcoholic patient in hospital who has been NBM or has reduced intake

Question 5

Signs of Wernicke’s Encephalopathy

Answer 5

Mental status change, ophthalmoplegia and gait dysfunction

Oculomotor findings: gaze palsy, sixth nerve palsy, Impaired vestibulo-ocular reflexes
Ataxia
Confusion
Coma
Miosis, anisocoria, light-near dissociation
Papilloedema, retinal haemorrhages
Tachycardia, hypotensions
Hypothermia or hyperthermia
Hearing loss, seizures, spastic paraparesis

Question 6

Investigations for Wernicke’s Encephalopathy

Answer 6

Blood thiamine and vitamin B1: usually low
LFTs and albumin: Deranged if Hx of alcohol misuse
Therapeutic trial of parenteral feeding: clinical response to treatment

Capillary glucose: exclude hypoglycaemia

FBC: exclude infection
U+Es and renal function: exclude renal dysfunction
Serum magnesium: low in chronic alcohol misuse
Toxicology screen: exclude concomitant drug use
Serum ammonia: exclude decompensation of co-existent alcoholic liver disease

LP: exclude meningitis, encephalitis, SAH

CT/MRI head: low-density areas, involvement of the mammillary bodies, thalamus, periaqueductal grey matter, fourth ventricle, cerebellar vermis