Epidemiology

Etiology

• Wernicke encephalopathy and Korsakoff syndrome are caused by a severe deficiency of thiamine (vitamin B1).
• Thiamine deficiency can be due to:
  • Chronic heavy alcohol use (most common): due to inadequate intake, absorption, and hepatic storage of thiamine
  • Inadequate intake
    • Thiamine-deficient diets
    • Anorexia nervosa, starvation
      • In patients with low glucose intake, thiamine deficiency may be asymptomatic. However, this patient ingested a large quantity of glucose, which likely rapidly depleted her limited thiamine stores.
  • Malabsorption

Pathophysiology

• Thiamine deficiency → decreased cerebral glucose metabolism and mitochondrial dysfunction → depleted ATP and increased free radicals → injury of neuronal elements (e.g., myelin sheaths, blood-brain-barrier, decreased neurotransmitters, etc.) → impaired axonal conduction → symptoms of Wernicke encephalopathy and Korsakoff syndrome
• In patients with Korsakoff syndrome: long term thiamine deficiency → permanent damage to components of the limbic system (e.g., mammillary bodies, anterior thalamic nuclei) → atrophy of these components → memory loss, apathy, and disrupted emotional processing

Clinical features

Wernicke encephalopathy (acute, reversible)

• Should be suspected in any patient with a history of chronic heavy alcohol use who presents with one/more symptoms of the classic triad of Wernicke encephalopathy
  1. Confusion (most common)
     • Disorientation, impaired vigilance, and cognitive deficits
  2. Oculomotor dysfunction
     • Due to involvement of the CN III, CN IV, and CN VI nuclei
     • Gaze-induced horizontal/vertical nystagmus (most common)
     • Diplopia
     • Conjugate gaze palsy
  3. Gait ataxia: wide-based, small steps
     • Due to a combination of peripheral neuropathy, vestibular dysfunction, and cerebellar dysfunction
     • Romberg test positive

Diagnostics

Treatment