• Clinical science

Wernicke encephalopathy and Korsakoff syndrome

Summary

Wernicke encephalopathy is an acute, reversible condition caused by severe thiamine (vitamin B1) deficiency, often due to chronic heavy alcohol use. Inadequate intake, impaired absorption, or increased excretion of thiamine can also cause Wernicke encephalopathy. The classical triad of confusion, oculomotor dysfunction, and gait ataxia is seen in about a third of patients. Chronic thiamine deficiency, especially in patients with alcohol use disorder, frequently progresses to Korsakoff syndrome, which is characterized by irreversible personality changes, anterograde and retrograde amnesia, and confabulation. The diagnosis of both Wernicke encephalopathy and Korsakoff syndrome is clinical, but laboratory tests confirming thiamine deficiency and brain imaging may be considered in ambiguous cases. Wernicke encephalopathy is an emergency and requires immediate high-dose IV thiamine therapy followed by long-term thiamine supplementation. Abstaining from alcohol is vital in both conditions. While the prognosis in Wernicke encephalopathy is good if treated accordingly, that in Korsakoff syndrome is generally poor.

Etiology

References:[1][2]

Pathophysiology

References:[1]

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)
    2. Oculomotor dysfunction
      • Gaze-induced horizontal/vertical nystagmus (most common)
      • Diplopia
      • Conjugate gaze palsy
      • Other manifestations (less common): anisocoria, delayed pupillary response, ptosis, scotoma, vertical gaze palsy, isolated vertical gaze palsy, internuclear ophthalmoplegia, and complete ophthalmoplegia
    3. Gait ataxia: wide-based, small steps
  • Other manifestations
    • Autonomic dysfunction: hypotension, syncope, hypothermia
    • Peripheral neuropathy: paresthesia, foot drop, decreased deep tendon reflexes
    • Cardiovascular dysfunction: tachycardia, exertional dyspnea
    • Diencephalic involvement: vegetative disorders (coma and stupor)

Korsakoff syndrome (chronic, irreversible)

Korsakoff syndrome is a late development in patients with persistent vitamin B1 deficiency. It is most often seen in thiamine deficiency due to chronic heavy alcohol use.

  • Confabulation: Patients produce fabricated memories to fill in lapses of memory.
  • Anterograde and retrograde amnesia (anterograde > retrograde)
  • Personality changes (in frontal lobe lesions): apathy, indifference, decrease in executive function
  • Disorientation to time, place, and person
  • Hallucinations


Wernicke's COAT: Confusion, Oculomotor dysfunction, Ataxia, and Thiamine administration (see Treatment section)
Korsakoff's CART: Confabulation, Anterograde and Retrograde amnesia, and altered Temper

Although often grouped together as a single syndrome (Wernicke-Korsakoff syndrome), the two conditions are distinct entities with different presentations, and, while both are due to severe chronic thiamine deficiency, Wernicke encephalopathy is reversible whereas Korsakoff syndrome is not.

References:[3][4][5][6][2]

Diagnostics

MRI signs of periventricular hemorrhage and/or atrophy of mammillary bodies is a frequent finding in both Wernicke encephalopathy and Korsakoff syndrome!

Laboratory tests or imaging should not delay treatment!

References:[1][3][2]

Pathology

References:[7][2]

Differential diagnoses

References:[1][2]

The differential diagnoses listed here are not exhaustive.

Treatment

Because glucose increases thiamine demand and will worsen encephalopathy, IV glucose infusions must be administered AFTER thiamine!

References:[3][8]

Prognosis

References:[3][5]