What are the main features of Wernicke's (Wernicke's) encephalopathy?

Main Features of Wernicke's Encephalopathy

Wernicke's encephalopathy is characterized by the classic clinical triad of confusion/encephalopathy, ataxia, and ocular abnormalities (particularly nystagmus), though all three features are present in only about 10% of cases. 1, 2

Clinical Presentation

The main clinical features include:

• Neurological manifestations:

  • Confusion and altered mental status (encephalopathy)
  • Ataxia (particularly gait ataxia)
  • Ocular abnormalities:
    • Nystagmus (most common ocular finding)
    • Ophthalmoplegia (eye movement paralysis)
    • Diplopia (double vision)
  • Other neurological signs:
    • Myoclonus and hyperreflexia 3
    • Hand tremor (particularly in early and middle phases) 3
    • Memory impairment

• Progression of symptoms:

  • Early symptoms may include personality changes, indifference, anxiety, and irritability 3
  • Can progress to coma if left untreated 3
  • Oculomotor signs typically improve within days of treatment, while ataxia and confusion may take weeks to resolve 1

Risk Factors

Wernicke's encephalopathy results from thiamine (vitamin B1) deficiency and is commonly associated with:

• Chronic alcoholism
• Bariatric surgery
• Hyperemesis gravidarum
• Prolonged intravenous feeding without adequate supplementation
• Malnutrition or malabsorption
• Persistent vomiting
• Fasting for more than 72 hours 1

Diagnostic Considerations

• Clinical diagnosis can be challenging as the full triad appears in only 10% of cases 2
• Brain MRI is the imaging modality of choice, showing:
  • Increased T2 signal in the medial thalamus bilaterally 2
  • Signal abnormalities in mammillary bodies, periaqueductal regions of the midbrain 4
  • In atypical cases, lesions may appear in cranial nerve nuclei and cerebellum 5
  • Contrast enhancement may be present in acute stages, reflecting blood-brain barrier disruption 4

Differential Diagnosis

Wernicke's encephalopathy must be differentiated from:

• Cerebral hemorrhage and edema
• Substance abuse complications
• Hyponatremia (particularly challenging as symptoms are very similar)
• Hypoglycemia
• Metabolic alkalosis
• Subdural hematoma
• Encephalitis
• Korsakoff syndrome (often follows untreated Wernicke's encephalopathy) 3

Treatment Implications

• Immediate administration of thiamine is essential to prevent progression to permanent neurological damage
• For Wernicke-Korsakoff syndrome, thiamine hydrochloride should be administered IV at an initial dose of 100 mg, followed by IM doses of 50-100 mg daily until the patient is consuming a regular diet 6
• The American College of Nutrition recommends 500 mg IV three times daily for 3-5 days, followed by 250 mg IV daily for at least 3-5 additional days 1
• Thiamine must be given before any glucose-containing solutions to prevent worsening of symptoms 1

Clinical Pitfalls and Caveats

• Delayed diagnosis and treatment can lead to permanent neurological damage or death, with up to 20% of cases being fatal without adequate treatment 1
• In immunocompromised patients, the neurological symptoms may be mistakenly attributed to infectious or neoplastic etiologies 2
• Following bariatric surgery, symptoms can develop as early as six weeks post-procedure 7
• Given the relative safety of thiamine supplementation, there should be a low threshold for initiating therapy when Wernicke's encephalopathy is suspected 2