FFS: Wernicke Encephalopathy

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History

• Described by Carl Wernicke in 1881 as a triad of confusion, ophthalmoplegia, gait ataxia, with punctate haemorrhages in the brainstem
• Sergei Korsakoff described a chronic amnestic syndrome in alcoholics in 1888–1889
• In teh 1930s Thiamine (vitamin B1) deficiency is experimentally shown to induce Wernicke-like pathology, confirming the metabolic basis of the syndrome.

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Pathophysiology

• Caused by deficiency of thiamine, essential in:
  • Carbohydrate metabolism
  • Pentose-phosphate pathway
  • Krebs cycle

Contributing factors:

• Alcohol inhibits GI absorption of thiamine
• Chronic liver disease impairs thiamine activation and storage

Untreated progression:

• Wernicke’s → Korsakoff’s psychosis:
  • Retrograde and anterograde amnesia
  • Confabulation

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Causes

Thiamine deficiency may result from:

1. Starvation (rare in Australia)
2. Poor nutrition with vomiting:
   • Chronic alcohol abuse (most common)
   • Hyperemesis gravidarum
   • Eating disorders
   • Malabsorption syndromes
3. Hyperalimentation
4. Rare transketolase enzyme defects

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Clinical features

Classic triad:

1. Ophthalmoplegia
2. Ataxia
3. Confusion / altered conscious state

Only ~1/3 of patients present with all three features.

Detailed manifestations:

• Ophthalmoplegia:
  • Horizontal nystagmus (most common)
  • Bilateral lateral rectus palsies
  • Conjugate gaze palsies
• Ataxia:
  • Acute: vestibular dysfunction (normal hearing)
  • Subacute/chronic: cerebellar or mixed dysfunction
  • Wide-based, unsteady gait
• Altered mental state:
  • Confusion, drowsiness
  • Coma (rarely, sole presentation)

Other signs:

• Peripheral neuropathy (esp. lower limbs)
• Autonomic dysfunction:
  • Hypothermia, hypotension
• Wet beri beri (heart failure)

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Investigations

Diagnosis is clinical, but imaging may support.

Blood tests:

1. FBC
2. U&Es, glucose
3. Magnesium, calcium, phosphate
4. LFTs
5. Blood alcohol
6. Coagulation profile

Other tests:

• CXR: screen for infection
• ECG: as in any unwell patient
• CT brain: rule out structural causes (e.g. haemorrhage)
• MRI brain: most sensitive
  • Pathognomonic: enhanced mammillary bodies on T1 with gadolinium
  • Also peri-aqueductal and periventricular lesions

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Management

1. IV fluids
   • Rehydrate and stabilise
2. Sedation (if needed)
   • Diazepam / droperidol for agitation or DTs
3. Thiamine therapy
   • Give before any glucose administration
   • Thiamine 500 mg IV over 30 min, TDS for 5–7 days
   • Then 100 mg IV/IM daily for 1–2 weeks or until clinical improvement ceases
   • Follow with 100 mg daily orally, plus multivitamin
4. Correct electrolytes
   • Magnesium (required for thiamine function)
   • Potassium
   • Glucose
5. Monitor for alcohol withdrawal syndromes

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Disposition

• All suspected cases must be admitted
• Mortality without treatment is ~10%

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References

Publications

• Ota Y, Capizzano AA, Moritani T, Naganawa S, Kurokawa R, Srinivasan A. Comprehensive review of Wernicke encephalopathy: pathophysiology, clinical symptoms and imaging findings. Jpn J Radiol. 2020 Sep;38(9):809-820.

FOAMed

• Cadogan M. Wernicke encephalopathy. LITFL
• Cadogan M. Carl Wernicke (1848–1905). LITFL
• Cadogan M. Sergei Sergeivich Korsakoff (1854–1900). LITFL