cerebrovascular
epilepsy
infectious
movement-disorders
neurodegenerative
Wernicke Encephalopathy
VERSION: 1.0
CREATED: January 29, 2026
REVISED: January 29, 2026
STATUS: Approved
DIAGNOSIS: Wernicke Encephalopathy
ICD-10: E51.2 (Wernicke encephalopathy), E51.11 (Dry beriberi), F10.96 (Alcohol use, unspecified with alcohol-induced persisting amnestic disorder)
CPT CODES: 82962 (Fingerstick glucose), 80048 (BMP), 83735 (Magnesium), 84100 (Phosphorus), 85025 (CBC), 80076 (LFTs, albumin), 82140 (Ammonia), 83605 (Lactate), 80320 (Blood alcohol level), 84425 (Thiamine level (whole blood or RBC transketolase)), 84443 (TSH), 80307 (Urine drug screen), 85610 (Coagulation studies (PT/INR)), 70551 (MRI brain with FLAIR/DWI), 70450 (CT head), 95816 (EEG), 62270 (Lumbar puncture), 96374 (Thiamine IV (high-dose) - Suspected/Confirmed WE)
SYNONYMS: Wernicke encephalopathy, WE, Wernicke syndrome, Wernicke-Korsakoff syndrome, WKS, thiamine deficiency encephalopathy, Wernicke-Korsakoff, acute thiamine deficiency, alcohol-related brain damage, nutritional encephalopathy
SCOPE: Diagnosis and treatment of Wernicke encephalopathy in adults including classic and non-alcoholic etiologies. Covers acute treatment, prevention of Korsakoff syndrome, and at-risk populations. Applies primarily to ED, hospital, and ICU settings as this is a medical emergency. Excludes chronic Korsakoff syndrome management.
DEFINITIONS:
- Wernicke Encephalopathy (WE): Acute neuropsychiatric syndrome from thiamine (vitamin B1) deficiency; classically presents with triad of encephalopathy, oculomotor dysfunction, and ataxia
- Korsakoff Syndrome: Chronic amnestic syndrome (anterograde > retrograde amnesia, confabulation) following untreated or inadequately treated WE
- Wernicke-Korsakoff Syndrome (WKS): Combined acute WE with subsequent Korsakoff syndrome
- Classic Triad: Mental status changes, oculomotor dysfunction, gait ataxia (only ~10-16% present with all three)
- At-Risk Populations: Alcohol use disorder, malnutrition, hyperemesis gravidarum, bariatric surgery, chronic illness, prolonged fasting, refeeding, dialysis, cancer, AIDS
PRIORITY KEY: STAT = Immediate | URGENT = Within hours | ROUTINE = Standard | EXT = Extended/atypical cases | - = Not applicable to this setting
1. LABORATORY WORKUP
Test
ED
HOSP
OPD
ICU
Rationale
Target Finding
Fingerstick glucose (CPT 82962)
STAT
STAT
-
STAT
Hypoglycemia; DO NOT give dextrose before thiamine
Normal; treat hypoglycemia AFTER thiamine
BMP (CPT 80048)
STAT
STAT
-
STAT
Electrolytes; magnesium essential for thiamine function
Correct abnormalities
Magnesium (CPT 83735)
STAT
STAT
-
STAT
Required cofactor for thiamine; replace if low
>2.0 mg/dL
Phosphorus (CPT 84100)
STAT
STAT
-
STAT
Refeeding syndrome risk
>2.5 mg/dL
CBC (CPT 85025)
STAT
ROUTINE
-
STAT
Macrocytic anemia (alcohol, B12/folate deficiency)
Document
LFTs, albumin (CPT 80076)
STAT
ROUTINE
-
STAT
Hepatic dysfunction; malnutrition
Document
Ammonia (CPT 82140)
STAT
STAT
-
STAT
Hepatic encephalopathy (may coexist)
Normal
Lactate (CPT 83605)
STAT
STAT
-
STAT
Thiamine deficiency causes lactic acidosis
Normal
Blood alcohol level (CPT 80320)
STAT
STAT
-
-
Document; withdrawal risk
Document
1B. Extended Labs
Test
ED
HOSP
OPD
ICU
Rationale
Target Finding
Thiamine level (whole blood or RBC transketolase) (CPT 84425)
-
ROUTINE
-
ROUTINE
Confirms deficiency (do not delay treatment for result)
Low (but treat empirically)
Vitamin B12, folate (CPT 82607+82746)
-
ROUTINE
ROUTINE
-
Often co-deficient in alcohol use
Normal; supplement if low
TSH (CPT 84443)
-
ROUTINE
-
-
Exclude thyroid dysfunction
Normal
Urine drug screen (CPT 80307)
STAT
ROUTINE
-
-
Concomitant intoxication
Document
Coagulation studies (PT/INR) (CPT 85610)
-
ROUTINE
-
ROUTINE
Liver disease; coagulopathy
Normal
1C. Specialized Labs (If Diagnosis Uncertain)
Test
ED
HOSP
OPD
ICU
Rationale
Target Finding
RBC transketolase activity
-
EXT
EXT
-
Functional thiamine status; low in deficiency
Low activity
Thiamine pyrophosphate (TPP) effect
-
EXT
EXT
-
>25% increase suggests deficiency
Normal
CSF analysis
-
EXT
-
-
If meningitis suspected; usually normal in WE
Normal; mild protein elevation possible
2. DIAGNOSTIC IMAGING & STUDIES
2A. Neuroimaging
Study
ED
HOSP
OPD
ICU
Timing
Target Finding
Contraindications
MRI brain with FLAIR/DWI (CPT 70551)
-
URGENT
-
URGENT
After stabilization; supports diagnosis
Bilateral symmetric T2/FLAIR hyperintensity in medial thalami, mammillary bodies, periaqueductal gray, tectal plate
Pacemaker, metal
CT head (CPT 70450)
STAT
STAT
-
STAT
Exclude other causes (hemorrhage, mass); often normal in WE
No mass, hemorrhage
None
2B. MRI Findings in Wernicke Encephalopathy
Location
Sensitivity
Notes
Medial thalami (bilateral)
High
Most specific finding
Mammillary bodies
High
Atrophy in chronic cases
Periaqueductal gray
High
Classic location
Tectal plate
Moderate
Around cerebral aqueduct
Dorsal medulla
Moderate
Vagal nuclei area
Cerebellum (vermis)
Low-Moderate
Ataxia correlate
Cortex (atypical)
Low
Non-alcoholic WE may show cortical involvement
2C. Additional Studies
Study
ED
HOSP
OPD
ICU
Timing
Target Finding
Contraindications
EEG (CPT 95816)
-
ROUTINE
-
ROUTINE
If seizure suspected or encephalopathy unclear
Diffuse slowing (non-specific)
None
Lumbar puncture (CPT 62270)
-
EXT
-
EXT
If meningitis or encephalitis suspected
Normal; r/o infection
Mass lesion
3. TREATMENT
3A. Acute Thiamine Replacement (CRITICAL - Do Not Delay)
Treatment
Route
Indication
Dosing
Contraindications
Monitoring
ED
HOSP
OPD
ICU
Thiamine IV (high-dose) - Suspected/Confirmed WE (CPT 96374)
IV
-
500 mg :: IV :: TID :: 500 mg IV TID × 3-5 days (in 100 mL NS over 30 min); then 250 mg IV daily × 3-5 days; then oral
Rare anaphylaxis (give slowly)
Anaphylaxis (rare); clinical response
STAT
STAT
-
STAT
Thiamine IV (prophylaxis - at-risk patients) (CPT 96374)
IV
-
200-500 mg :: IV :: TID :: 200-500 mg IV TID × 3 days; then oral
Same
Same
STAT
STAT
-
STAT
3B. Maintenance Thiamine
Treatment
Route
Indication
Dosing
Contraindications
Monitoring
ED
HOSP
OPD
ICU
Thiamine oral (after IV course)
IV
-
100 mg :: PO :: TID :: 100 mg TID × weeks to months; indefinitely if ongoing risk
None
Compliance; symptoms
-
ROUTINE
ROUTINE
-
Thiamine IM (if IV not possible, unreliable oral)
IM
-
250 mg :: IM :: daily :: 250 mg IM daily × 3-5 days
Coagulopathy (relative)
Clinical response
STAT
ROUTINE
ROUTINE
-
3C. Electrolyte Replacement
Treatment
Route
Indication
Dosing
Contraindications
Monitoring
ED
HOSP
OPD
ICU
Magnesium sulfate IV (CPT 96374)
IV
-
1-2 g :: IV :: - :: 1-2 g IV over 1-2 hours; repeat as needed; target Mg >2.0
Renal failure (adjust dose); heart block
Mg levels; reflexes
STAT
STAT
-
STAT
Potassium replacement
-
-
N/A :: - :: per protocol :: Per deficit; often needed with Mg
Renal failure; hyperkalemia
K+ levels
STAT
STAT
-
STAT
Phosphorus replacement
IV
-
N/A :: IV :: per protocol :: If low (refeeding); K-Phos or Na-Phos IV/PO
Hypercalcite; renal failure
Phos levels
STAT
STAT
-
STAT
3D. Glucose Administration
Treatment
Route
Indication
Dosing
Pre-Treatment Requirements
Contraindications
Monitoring
ED
HOSP
OPD
ICU
THIAMINE BEFORE GLUCOSE
-
-
N/A :: - :: per protocol :: ALWAYS give thiamine before or with dextrose/carbohydrates; glucose metabolism depletes thiamine
-
None
Give thiamine first
STAT
STAT
-
STAT
Dextrose (if hypoglycemic)
IV
-
25-50 mL :: IV :: - :: D50 25-50 mL IV or D10 infusion; AFTER thiamine
-
Give thiamine first
Glucose levels
STAT
STAT
-
STAT
3E. Alcohol Withdrawal Prevention/Treatment
Treatment
Route
Indication
Dosing
Contraindications
Monitoring
ED
HOSP
OPD
ICU
Benzodiazepines (symptom-triggered or scheduled)
IV
-
1-4 mg :: IV :: PRN :: Lorazepam 1-4 mg IV q15min PRN (CIWA-guided); or scheduled dosing if severe
Respiratory depression; caution with hepatic impairment
CIWA score; sedation; respiratory status
STAT
STAT
-
STAT
Folate
PO
-
1 mg :: PO :: daily :: 1 mg daily
None
None
-
ROUTINE
ROUTINE
-
Multivitamin
-
-
N/A :: - :: daily :: Daily
None
None
-
ROUTINE
ROUTINE
-
3F. Nutritional Support
Treatment
Route
Indication
Dosing
Contraindications
Monitoring
ED
HOSP
OPD
ICU
Nutrition consult
-
-
N/A :: - :: per protocol :: Refeeding protocol; caloric needs
None
Refeeding syndrome
-
ROUTINE
-
ROUTINE
Gradual refeeding
-
-
N/A :: - :: per protocol :: Start low calorie (10-15 kcal/kg); advance slowly
None
Phosphorus, K+, Mg, glucose
-
ROUTINE
-
ROUTINE
4. OTHER RECOMMENDATIONS
4A. At-Risk Populations (Prophylactic Thiamine)
Population
Risk Level
Prophylaxis
Chronic alcohol use disorder
High
Thiamine 200-500 mg IV TID × 3 days before/with any glucose
Hyperemesis gravidarum
High
Thiamine 100-200 mg IV daily; replace before IV dextrose
Bariatric surgery patients
High
Thiamine supplementation pre- and post-op; monitor
Prolonged fasting/starvation
High
Thiamine before refeeding
TPN without thiamine
High
Ensure thiamine in TPN
Chronic dialysis
Moderate
Oral thiamine supplementation
Cancer/chemotherapy
Moderate
Monitor; supplement if poor nutrition
AIDS/HIV
Moderate
Monitor; supplement
Critically ill/ICU patients
Moderate
Consider empiric thiamine in encephalopathy
Anorexia nervosa
High
Thiamine before refeeding
4B. Referrals & Consults
Recommendation
ED
HOSP
OPD
ICU
Indication
Neurology
-
ROUTINE
-
ROUTINE
Diagnosis confirmation; atypical presentations; persistent deficits
Addiction medicine/psychiatry
-
ROUTINE
ROUTINE
-
Alcohol use disorder; relapse prevention
Nutrition/dietitian
-
ROUTINE
ROUTINE
ROUTINE
Refeeding; nutritional rehabilitation
Social work
-
ROUTINE
ROUTINE
-
Discharge planning; resources; housing
Physical/occupational therapy
-
ROUTINE
ROUTINE
-
Gait ataxia; functional rehabilitation
Speech therapy
-
ROUTINE
-
-
Swallowing assessment if impaired
Neuropsychology
-
-
ROUTINE
-
Cognitive assessment if persistent deficits
4C. Patient/Family Instructions
Recommendation
ED
HOSP
OPD
Wernicke encephalopathy is a medical emergency caused by thiamine (vitamin B1) deficiency
-
ROUTINE
ROUTINE
Without treatment, permanent brain damage (Korsakoff syndrome) can occur
-
ROUTINE
ROUTINE
Take thiamine supplements as prescribed
-
ROUTINE
ROUTINE
If alcohol use disorder: Thiamine is critical; take before drinking if relapse
-
ROUTINE
ROUTINE
Alcohol cessation is essential to prevent recurrence
-
ROUTINE
ROUTINE
Eat a balanced diet; malnutrition worsens risk
-
ROUTINE
ROUTINE
Report confusion, vision changes, unsteady walking
ROUTINE
ROUTINE
ROUTINE
SAMHSA helpline 1-800-662-4357 for alcohol treatment resources
-
-
ROUTINE
4D. Prevention Strategies
Recommendation
ED
HOSP
OPD
Give thiamine BEFORE or WITH any glucose-containing fluids in at-risk patients
ROUTINE
ROUTINE
-
Empiric thiamine for any encephalopathy in at-risk patients
STAT
STAT
-
Thiamine supplementation for all patients with alcohol use disorder
ROUTINE
ROUTINE
ROUTINE
Thiamine in TPN formulations
-
ROUTINE
-
Pre-operative thiamine for bariatric surgery patients
-
ROUTINE
ROUTINE
5. DIFFERENTIAL DIAGNOSIS
Alternative Diagnosis
Key Distinguishing Features
Tests to Differentiate
Hepatic encephalopathy
Asterixis; elevated ammonia; liver disease
Ammonia level; LFTs
Alcohol intoxication
Positive alcohol level; resolves as level clears
Blood alcohol; clinical course
Alcohol withdrawal
Tremor, tachycardia, diaphoresis; after cessation
History; CIWA score
Hypoglycemia
Low glucose; rapid response to dextrose
Fingerstick glucose
Meningitis/encephalitis
Fever, meningismus, CSF abnormalities
LP; CSF analysis
Stroke (thalamic, brainstem)
Acute onset; focal signs; imaging findings
MRI/CT; usually asymmetric
Central pontine myelinolysis
History of rapid sodium correction; imaging
MRI; sodium history
Normal pressure hydrocephalus
Triad: gait, dementia, incontinence; enlarged ventricles
MRI; LP trial
Drug intoxication
Toxicology positive; specific syndromes
Tox screen; history
Non-convulsive status epilepticus
EEG shows seizure activity
EEG
Posterior reversible encephalopathy (PRES)
Hypertension; posterior white matter edema
MRI; BP
6. MONITORING PARAMETERS
Parameter
ED
HOSP
OPD
ICU
Frequency
Target/Threshold
Action if Abnormal
Mental status (GCS, orientation)
STAT
q4h
Every visit
q1-2h
Per setting
Improving
Continue thiamine; r/o other causes
Oculomotor exam (nystagmus, gaze palsy)
STAT
Daily
Every visit
Daily
Daily until improved
Improving
Continue treatment
Gait/ataxia assessment
-
Daily
Every visit
-
Daily until improved
Improving
PT/OT; continue treatment
Magnesium
STAT
Daily until stable
PRN
q6-12h
Per setting
>2.0 mg/dL
Replace
Potassium
STAT
Daily until stable
PRN
q6-12h
Per setting
3.5-5.0 mEq/L
Replace
Phosphorus
STAT
Daily until stable
PRN
q12h
Per setting
>2.5 mg/dL
Replace
Blood glucose
STAT
q6h initially
PRN
q4-6h
Per setting
80-180 mg/dL
Give thiamine before glucose
CIWA score (if alcohol withdrawal risk)
STAT
q4-8h
-
q2-4h
Per protocol
<10
Benzodiazepines PRN
7. DISPOSITION CRITERIA
Disposition
Criteria
Admit to hospital
All suspected or confirmed Wernicke encephalopathy; need IV thiamine
ICU admission
Altered mental status; severe withdrawal risk; hemodynamic instability
Discharge criteria
Mental status normalized; tolerating oral thiamine; safe discharge plan
Neurology follow-up
2-4 weeks post-discharge; assess for persistent deficits
Addiction medicine follow-up
If alcohol use disorder; outpatient treatment program
Urgent readmission
Recurrent symptoms; inability to take oral thiamine; relapse
8. EVIDENCE & REFERENCES
Recommendation
Evidence Level
Source
High-dose IV thiamine (500 mg TID) for suspected WE
Class II, Level B
EFNS guidelines ; Cochrane review (limited RCT data but expert consensus)
Thiamine before glucose in at-risk patients
Class I (practice standard)
Physiologic rationale; case reports of precipitation
MRI typical findings in WE
Class II, Level B
Multiple case series; imaging studies
Magnesium replacement essential
Class II, Level B
Cofactor for thiamine-dependent enzymes
Oral thiamine poorly absorbed in alcoholics
Class II
Pharmacokinetic studies; supports IV administration
Prophylactic thiamine in at-risk populations
Class II, Level B
Observational data; prevention superior to treatment
Classic triad present in minority
Class II
Autopsy studies show only 10-16% have all three features
CLINICAL FEATURES
Classic Triad (present in only 10-16%):
1. Encephalopathy: Confusion, disorientation, apathy, inattention, obtundation, coma
2. Oculomotor dysfunction: Nystagmus (horizontal > vertical), lateral rectus palsy (CN VI), conjugate gaze palsy
3. Gait ataxia: Wide-based, unsteady; may be unable to walk
Other Features:
- Hypothermia
- Hypotension
- Tachycardia
- Peripheral neuropathy (feet > hands)
- Vestibular dysfunction without hearing loss
Caine Criteria (2 of 4 for diagnosis in alcoholics):
1. Dietary deficiency
2. Oculomotor abnormalities
3. Cerebellar dysfunction
4. Either altered mental status or mild memory impairment
NOTES
Wernicke encephalopathy is a MEDICAL EMERGENCY - treatment should not be delayed for diagnostic confirmation
Classic triad is present in only 10-16% of cases; have low threshold to treat empirically
ALWAYS give thiamine BEFORE or SIMULTANEOUSLY with glucose/dextrose in at-risk patients
Oral thiamine is poorly absorbed in alcoholics; IV route is essential for acute treatment
Magnesium is a required cofactor; replace aggressively
High-dose IV thiamine (500 mg TID) is recommended; standard doses (100 mg) are inadequate for acute WE
MRI may be normal in early WE; clinical diagnosis takes precedence
Without treatment, mortality is ~20% and ~80% develop Korsakoff syndrome
Korsakoff syndrome (chronic amnestic state) is largely irreversible once established
Oculomotor abnormalities respond quickly (hours to days); ataxia and encephalopathy take longer
Non-alcoholic WE (hyperemesis, bariatric surgery, malnutrition) may have atypical presentations
Thiamine is safe; there is no downside to empiric treatment
CHANGE LOG
v1.0 (January 29, 2026)
- Initial template creation
- High-dose IV thiamine protocol emphasized
- At-risk populations comprehensive list
- Caine criteria included
- MRI findings detailed
- Thiamine before glucose emphasized
- Prevention strategies included