An acute, reversible condition caused by severe thiamine (vitamin B1) deficiency, often due to chronic heavy alcohol use

Demographics

• Incidence higher in developing countries due to vitamin deficiencies and malnutrition
• More common in males
• Thiamine deficiency very common among critically ill patients (they have risk factors – reduced nutritional intake, diuresis, systemic inflammation, dialysis)

Aetiology

• Severe deficiency of thiamine which can be due to:
• Chronic heavy alcohol use (most common) -> inadequate intake, absorption and hepatic storage of thiamine
• Inadequate intake – thiamine-deficient diets, anorexia nervosa, starvation
• Malabsorption
• Increased demand (hypermetabolic states) – pregnancy and lactation, hyperthyroidism, systemic diseases, malignancy
• Increased loss – diarrhoea, hyperemesis, dialysis

Pathophysiology

• The brain requires a constant source of thiamine to function properly
• Thiamine pyrophosphate (TPP) is the active form of thiamine and a cofactor for important enzymes involved in cerebral glucose and energy metabolism
• Thiamine deficiency → decreased cerebral glucose metabolism and mitochondrial dysfunction → depleted ATP and increased free radicals → injury of neuronal elements e.g. myelin sheath, blood-brain barrier, decreased neurotransmitters → impaired axonal conduction → symptoms of Wernicke encephalopathy and Korsakoff syndrome