creation date: 2026-08-20 16:19
tags: Pathologies
Wernicke Encephalopathy
Background
Definitions
Wernicke encephalopathy is a neurologic complication of thiamine (vitamin B1) deficiency, specifically the acute phase which is emergent and potentially fatal.
WE is often combined with Korsakoff syndrome to represent both the acute and chronic stages of the disease.
Risk Factors & Etiology
WE is associated with:
- Chronic heavy alcohol use
- Poor nutrition caused by malabsorption, poor dietary intake, increased metabolic requirement (eg. during systemic illness), increased loss of the water-soluble vitamin thiamine
- Anorexia nervosa
- Hyperemesis of pregnancy
- Prolonged enteral feeding without proper supplementation
- Prolonged fasting or starvation
- Refeeding syndrome
- GI disease or surgery
- Systemic malignancy
Pathogenesis
Thiamine is a cofactor for several key enzymes important for energy metabolism. As such, thiamine requirements depend on the metabolic rate whereby the demand increases during periods of high energy demand.
In cases with chronic heavy alcohol use, a combination of the following results in thiamine deficiency:
- Inadequate dietary intake
- Reduced GI absorption
- Decreased hepatic storage
- Impaired utilization
In cases of poor nutrition, thiamine intake/retention is insufficient for needs.
Regardless of cause, the deficiency causes dysfunction in cerebral energy utilization which initiates neuronal injury as regions with high metabolic requirements shut down. Neurotoxicity may be due to:
- Blood brain barrier breakdown
- NMDA receptor-mediated excitotoxicity
- Increased reactive oxygen species
Lesions form (both acute and chronic) which demonstrate neuronal loss.
Clinical Presentation
Signs & Symptoms
Classic triad:
- Encephalopathy (profound disorientation, indifference, and inattentiveness)
- Oculomotor dysfunction (nystagmus, lateral rectus palsy, conjugate gaze palsies)
- Gait ataxia (wide-based gait and slow, short-spaced steps)
Other signs:
- Stupor or coma
- Hypotension
- Hypothermia
- Evidence of protein-calorie malnutrition
- Vestibular dysfunction without hearing loss
- Peripheral neuropathy (often lower extremity)
- Hypothermia
Overt beriberi heart disease is rare but may manifest with tachycardia, exertional dyspnea, elevated cardiac output, and ECG abnormalities.
History & Physical Exam
History should include:
- Alcohol use
- Diet
Physical exam includes:
- Comprehensive neurological examination including cerebral testing
Diagnosis
Criteria
WE is a clinical diagnosis. The Caine criteria can be used, in which a diagnosis is made if 2/4 of the following are met:
- Dietary deficiency
- Oculomotor abnormalities
- Cerebellar dysfunction
- Either altered mental status or mild memory impairment
Work-up
Laboratory studies
There are no laboratory studies for diagnosis. Thiamine deficiency may be detected by measurement of erythrocyte thiamine transketolase activity (ETKA). However, this test is not readily available and thiamine repletion should not be delayed.
Measurements may be made to rule out causes of delirium.
In the presence of a fever or other suspicion of CNS infection, a lumbar puncture is required.
Imaging
Imaging is not necessary in all patients and should not delay treatment. However, may aid in ruling out alternatives diagnoses.
- CT or MRI head
Differential
Alternative diagnoses include:
- Delirium
- Acute ataxia
- Top-of-the-basilar stroke
- Hypoxic-ischemic encephalopathy after cardiac arrest
- Herpes simplex encephalitis
- Third ventricular tumour
Red Flags / Complications
In many patients with severe alcohol use, chronic complications persist even after treatment.
- Permanent horizontal nystagmus
- Ataxia and gait changes
As acute encephalopathy recedes, chronic neurologic complications can persist (80% of patients), resulting in Korsakoff syndrome.
Management
Acute treatment consist of IV thiamine:
- 500 mg thiamine over 30 minutes TID for 2 consecutive day
- Combined with other B vitamins
Do not administer glucose without thiamine (precipitate/worsen WE).
Daily oral thiamine should be continued after discharge until patient is no longer considered at risk.
- 100 mg thiamine daily
Note, daily dietary requirement is 1-2 mg but a higher dose is used because the poor absorption/utilization of many patients.