01Approach to the Critical Patient/attcp32

Immediate priorities

›Time-critical recognition: Wernicke encephalopathy (WE) preceding Korsakoff syndrome (KS)

›Classic WE triad (present in < 20% of autopsy-confirmed cases)

›Encephalopathy or altered mental status

›Oculomotor dysfunction (nystagmus, ophthalmoplegia)

›Gait ataxia

›Thiamine BEFORE any glucose-containing fluids in all at-risk patients

›IV dextrose without thiamine can precipitate or worsen acute WE

›Class I consensus recommendation

›Empiric parenteral thiamine if clinical suspicion — do not wait for lab confirmation

›Thiamine 500 mg IV TID for severe or uncertain cases

›Risk of withholding exceeds risk of treatment

Hemodynamic and airway threats

›Vital sign red flags requiring immediate action

›Hypothermia — autonomic dysfunction in severe thiamine deficiency

›Hypotension — wet beriberi or sepsis as comorbidity

›Tachycardia — high-output cardiac failure from thiamine deficiency

›Coma or GCS < 13 — escalate to resuscitation bay

›Airway protection assessment

›Aspiration risk from altered consciousness

›Intubation threshold lowered in severe acute WE

›Concurrent alcohol withdrawal seizure risk

Key clinical decision points

›Identify active WE vs established KS

›Active WE: potentially reversible with aggressive thiamine

›Established KS: largely irreversible; amnesia persists despite treatment

›Therapeutic trial: ocular improvement after IV thiamine supports active WE

›Identify concurrent alcohol withdrawal

02History/hx53

Presentation pattern

›Core amnestic syndrome

›Anterograde amnesia — inability to form new memories

›Cannot recall events from earlier the same day

›Preservation of procedural and implicit memory

›Retrograde amnesia — impaired recall of recent weeks to months

›Temporal gradient: remote memories better preserved than recent

›Confabulation — spontaneous or provoked fabrication to fill memory gaps

›Spontaneous confabulation more common in early KS

›Diminishes over months to years; amnesia persists

›Apathy and emotional blunting

›Bland affect without distress

›Lack of insight into deficits

Wernicke phase history

›Timeline reconstruction

›Acute confusion or delirium preceding amnesia

›Transition from WE to KS after Wernicke phase resolves

›Prior episodes of Wernicke encephalopathy (often undiagnosed)

›Visual symptoms or diplopia during acute phase

›Gait instability or falls

Risk factor history

›Alcohol use disorder — most common context

›Duration, quantity, frequency, and date of last drink

›Prior alcohol withdrawal seizures or delirium tremens

›Prior thiamine supplementation history

›Non-alcohol etiologies

›Hyperemesis gravidarum

›Bariatric surgery (especially Roux-en-Y gastric bypass)

03Physical Exam/exam47

Mental status and cognition

›Cognitive assessment

›Alert but profoundly amnestic — may appear superficially normal in conversation

›Orientation to time markedly impaired; place and person often intact

›Anterograde memory test: three-object recall at 5 minutes

›Retrograde memory probe: recent news events or personal history

›Confabulation elicited by memory probing

›Apathy and bland affect without apparent distress

›Lack of insight into memory deficits (anosognosia)

›Formal cognitive screening

›Montreal Cognitive Assessment (MoCA) or MMSE as baseline

›Executive function testing: impaired clock drawing or trail-making

Ocular exam

›Oculomotor findings

›Nystagmus: horizontal predominance, may also be vertical or gaze-evoked

›Lateral rectus palsy (CN VI) — abduction weakness

›Conjugate gaze palsy

›Impaired vestibulo-ocular reflex

›Ocular signs may have partially resolved if thiamine was given prior to exam

Gait and cerebellar exam

›Ataxia assessment

›Wide-based gait with truncal instability

›Inability to tandem walk

›Cerebellar signs: dysmetria on finger-to-nose testing

›Romberg test: positive with cerebellar involvement

Peripheral nervous system

›Peripheral neuropathy signs

›Diminished or absent ankle reflexes

04Differential Diagnosis/ddx50

Life-threatening mimics

›Acute conditions requiring immediate exclusion

›Hepatic encephalopathy

›ICD-10 K72.90

›Asterixis, elevated ammonia, liver disease stigmata

›Can coexist with KS in alcohol use disorder

›Herpes simplex encephalitis

›ICD-10 B00.4

›Fever, temporal lobe MRI involvement, CSF pleocytosis

›Rapid treatment with acyclovir if suspected

›Hypoglycemic encephalopathy

›ICD-10 E16.0

›Point-of-care glucose rules out in seconds

›Subdural hematoma

›ICD-10 S06.4

›Falls common in alcohol use disorder; CT excludes

›Status epilepticus or post-ictal state

›ICD-10 G41.9

›Tongue biting, incontinence, muscle soreness history

Alcohol-related neurological differentials

›Wernicke encephalopathy (active)

›ICD-10 E51.2

›Acute confusion + oculomotor signs + ataxia

›Reversible with early aggressive thiamine — key distinction from KS

›Alcohol-related dementia

›ICD-10 F10.97

›More global cognitive decline without disproportionate amnesia pattern

›Frontal predominance vs diencephalic amnesia in KS

05Laboratory Tests/lt38

Thiamine and nutritional markers

›Whole blood thiamine (erythrocyte thiamine diphosphate)

›Most accurate measure of thiamine status

›Serum and plasma thiamine levels unreliable

›Results take days — do not delay empiric treatment pending results

›Normal range 70-180 nmol/l; < 70 nmol/l confirms deficiency

›Serum magnesium

›Hypomagnesemia causes thiamine resistance — must correct concurrently

›Target serum magnesium > 0.8 mmol/l

›Folate and vitamin B12

›Co-supplementation required; deficiencies common in malnutrition

›Serum pyruvate

›Elevated pyruvate indicates B1 deficiency (thiamine required for pyruvate dehydrogenase)

Metabolic and organ function

›Comprehensive metabolic panel

›Electrolytes and glucose: glucose administration risk without thiamine

›Renal function: dosing adjustment and hydration guidance

›Liver function tests: hepatic disease common comorbidity

›Complete blood count

›Macrocytic anemia: folate or B12 deficiency

›Thrombocytopenia: alcohol-related bone marrow suppression

›Leukocytosis: concurrent infection

›Coagulation studies

›INR and PT: hepatic synthetic function assessment

›Vitamin K deficiency common in malnutrition

›Ammonia level

›Evaluation for concurrent hepatic encephalopathy

›Can coexist with KS; treatment diverges

06Diagnostic Tests/dt78

Scoring Systems

›Caine Criteria (operational criteria for WE diagnosis)

›Requires 2 of 4 criteria for diagnosis (sensitivity higher than classic triad)

›Criterion 1: dietary deficiency

›Criterion 2: oculomotor abnormalities

›Criterion 3: cerebellar dysfunction

›Criterion 4: altered mental state or mild memory impairment

›Higher sensitivity than classic triad (encephalopathy + ataxia + ophthalmoplegia)

›Clinical utility: identifies patients who benefit from empiric thiamine

›CIWA-Ar (Clinical Institute Withdrawal Assessment for Alcohol)

›Score > 8 indicates pharmacological treatment for withdrawal required

›Score > 15 indicates severe withdrawal risk

›Concurrent assessment required in alcohol-dependent patients

›Montreal Cognitive Assessment (MoCA)

›Sensitive to visuospatial and executive deficits

›Score < 26 of 30 abnormal; KS patients typically score 10-20

›Delayed recall subtest most sensitive for amnestic deficits

MRI

›Brain MRI with T2/FLAIR (primary diagnostic imaging for WE/KS)

›Typical acute WE findings (T2/FLAIR hyperintensities)

›Bilateral symmetric periaqueductal gray matter

›Medial thalami (bilateral paramedian)

›Mammillary bodies

›Tectal plate (dorsal midbrain)

›Floor of the fourth ventricle

›Sensitivity for acute WE: 53%; specificity 93%

›Atypical or alcohol-naive cases: cortical ribboning, cranial nerve nuclei

›Chronic KS MRI findings

›Mammillary body atrophy (most consistent finding)

›Thalamic atrophy and reduced volume

›Ventricular expansion (especially third ventricle)

›Frontal lobe atrophy

›Hippocampal volume reduction

›Diffusion-weighted imaging (DWI)

›Restricted diffusion in acute WE — useful for early diagnosis

›Hyperacute changes may precede T2/FLAIR abnormalities

›MRI contraindications

›Pacemaker or non-MRI-compatible implants require CT alternative

›Acute hemodynamic instability: CT head first to exclude structural emergency

CT

›CT head without contrast

›Sensitivity for WE/KS: approximately 13% — low diagnostic yield for Wernicke

›Primary role: exclude structural emergency

›Subdural hematoma in fall-risk patients

›Hemorrhagic stroke

›Mass lesion

›Chronic findings: third ventricle enlargement, cortical atrophy

›Mammillary body atrophy not reliably seen on CT

›CT indications over MRI

›Hemodynamic instability

›Metallic implant contraindication

›Inability to tolerate MRI duration (severe agitation)

›Initial emergency triage: rule out hemorrhage or herniation

Ultrasound

›Point-of-care ultrasound (POCUS)

›Cardiac assessment for wet beriberi

›High-output physiology: hyperdynamic left ventricle

›Dilated cardiomyopathy in chronic thiamine deficiency

›Pericardial effusion assessment

›IVC assessment for volume status

›Volume depletion common in malnourished patients

›Guides fluid resuscitation approach

›Hepatic assessment

›Cirrhosis features: nodular liver surface, increased echogenicity

›Ascites detection

›Portal hypertension evaluation

Additional diagnostic tests

›ECG

›Sinus tachycardia from wet beriberi or autonomic dysfunction

›Low voltage in thiamine-deficient cardiomyopathy

›Prolonged QTc with hypomagnesemia or hypokalemia

›Nonspecific ST-T wave changes

›EEG

›Diffuse slowing in theta range during active WE — non-specific but supportive

›Rule out non-convulsive status epilepticus if persistent altered consciousness

›Neuropsychological testing

›Formal assessment of anterograde and retrograde memory

›Executive function evaluation

›Essential for confirming KS diagnosis and establishing severity baseline

›Refer to neuropsychology at 4-6 weeks after stabilization

›Lumbar puncture

›CSF analysis to exclude herpes simplex encephalitis if fever or temporal lobe MRI changes

›CSF in KS: typically normal or mild protein elevation

07Disposition/dispo27

Admission indications

›All patients with suspected active WE require admission

›Parenteral thiamine cannot be administered at home

›Monitoring for thiamine response and alcohol withdrawal

›Nutritional optimization requires inpatient support

›ICU admission triggers

›Hypothermia or hemodynamic instability

›Coma or GCS < 13

›Active seizures or status epilepticus

›Severe concurrent alcohol withdrawal (CIWA > 15)

›Wet beriberi with high-output cardiac failure

›Concurrent sepsis or respiratory compromise

Level of care and transfer

›Medical ward admission criteria

›Stable vital signs with Wernicke features and functioning oral intake

›Established KS with safe social situation and outpatient follow-up arranged

›Alcohol withdrawal requiring pharmacological management but CIWA < 15

›Transfer considerations

›Neurology inpatient unit for complex atypical presentations

›Rehabilitation facility if intensive cognitive and physical rehabilitation needed

›Long-term care placement for 25% requiring institutionalization

Discharge criteria

›Requirements before discharge

›Stable neurological examination without active WE features

›Tolerating oral intake with oral thiamine prescribed

›Thiamine 100 mg PO daily prescription dispensed

›Alcohol cessation plan documented and addiction medicine referral made

›Safe social disposition confirmed — many KS patients cannot live independently

08Treatment/t61

Acute thiamine replacement

›Thiamine IV for active WE or suspected WE preceding KS

›Standard dosing: 100-200 mg IV three times daily for 3-5 days

›Followed by 50-100 mg IM/IV daily until oral intake is adequate

›Transition to 100 mg PO daily for long-term maintenance

›High-dose dosing for severe or non-alcohol cases: 500 mg IV TID

›Recommended for coma, hypothermia, or non-alcohol etiology

›Some experts recommend 500 mg IV TID for all acute WE cases

›Administer over 30 minutes to minimize anaphylaxis risk

›Rare anaphylaxis reported; resuscitation equipment at bedside

›Always administer BEFORE glucose-containing fluids

›Glucose administration depletes residual thiamine via increased demand

›Class I consensus recommendation

›Oral thiamine inadequate for acute treatment

›Erratic GI absorption in chronic alcohol users

›Use only for maintenance after parenteral course completed

›Maintenance dose: 100 mg PO daily indefinitely

Magnesium and co-nutrient replacement

›Magnesium repletion

›Hypomagnesemia causes thiamine resistance; correct concurrently

›Magnesium sulfate 2 g IV over 15-20 minutes for acute deficiency

›Target serum magnesium > 0.8 mmol/l

›Reassess and repeat dosing as needed

›Oral magnesium oxide 250-500 mg TID for ongoing maintenance

›Multivitamin supplementation

›Folate 1-5 mg PO daily

›Vitamin B12 1000 mcg IM if deficiency confirmed or suspected

›Multivitamin containing B-complex vitamins daily

›Electrolyte correction

›Potassium, phosphate, and calcium levels optimized

›Refeeding syndrome risk: monitor phosphate during refeeding

Alcohol withdrawal management

›Concurrent alcohol withdrawal treatment

›CIWA-Ar monitoring every 4-8 hours

›Lorazepam 1-2 mg IV/PO every 4-6 hours for CIWA > 8

›Titrate to CIWA < 8 without over-sedation

›Diazepam alternative: 5-10 mg PO/IV every 6 hours

›Phenobarbital adjunct for refractory withdrawal

›NEVER use beta-blockers alone — masks autonomic signs without preventing seizures

Chronic KS management

›Thiamine maintenance

›100 mg PO daily indefinitely — prevents further damage; does not reverse amnesia

›Alcohol abstinence support

›Addiction medicine referral

›Naltrexone 50 mg PO daily if no liver failure (LFTs < 3-5x ULN)

›Acamprosate 666 mg PO TID alternative for liver impairment

›Motivational interviewing and harm reduction counseling

›Cognitive rehabilitation

›Errorless learning techniques — exploit preserved implicit memory

›External memory aids: calendars, alarms, structured daily routines

›Intensive inpatient neurorehabilitation shown to produce sustained real-world benefits

›Memory notebook training for procedural learning tasks

›Nutritional optimization

›Balanced diet with thiamine-rich foods: whole grains, legumes, pork, fortified cereals

›Avoid carbohydrate loading without thiamine supplementation

›Dietitian consultation for structured nutritional plan

›Pharmacologic adjuncts for KS

›No established pharmacotherapy reverses established KS amnesia

›Memantine: explored with limited evidence; may show modest benefit in some patients

›Acetylcholinesterase inhibitors: explored without robust evidence

›Treat comorbid depression — SSRIs for depressive symptoms

›Psychiatric and behavioral management

›Monitor for apathy and flat affect — pharmacotherapy generally unhelpful

›Structured environment reduces behavioral dysregulation

›Caregiver psychoeducation essential for long-term management

09Special Populations/sp51

Pregnancy

›Hyperemesis gravidarum as KS etiology

›Prolonged vomiting prevents adequate thiamine intake

›Thiamine deficiency risk highest after 10-12 weeks of hyperemesis

›WE and KS reported in first and second trimester

›Thiamine safety in pregnancy

›Thiamine IV is safe in pregnancy — no teratogenic risk at therapeutic doses

›Class A/B safety profile; essential for fetal neurological development

›Delay is more dangerous than treatment; give empiric thiamine immediately

›Diagnostic considerations in pregnancy

›MRI without gadolinium preferred over CT (ionizing radiation avoidance)

›Gadolinium contrast avoided in pregnancy unless life-threatening indication

›Fetal monitoring appropriate during parenteral thiamine infusion

›Management approach

›Thiamine 100-500 mg IV TID for suspected WE

›Magnesium repletion safe in pregnancy (standard preeclampsia dosing)

›Obstetrics consultation for all cases during pregnancy

›Antiemetics to facilitate oral intake after acute thiamine therapy

Geriatric

›Epidemiology in older adults

›Non-alcohol etiologies more common: poor oral intake, malabsorption, polypharmacy

›Proton pump inhibitors and diuretics increase magnesium deficiency risk

›Cancer, post-surgical states, and chronic illness as risk factors

›Atypical presentation in geriatric patients

›Classic WE triad less likely to be complete

›Baseline cognitive impairment may obscure new amnestic deficits

›Falls presenting as ataxia may be attributed to frailty

›Thiamine dosing in geriatric patients

10Background/b61

Epidemiology

›Prevalence and incidence

›WE prevalence in general autopsy studies: 0.4-2.8%

›KS prevalence in alcohol use disorder: 10-24 per 100,000 population

›80-85% of untreated WE survivors progress to KS

›Up to 25% of KS patients require long-term institutionalization

›Demographic distribution

›Male predominance in alcohol-related KS (consistent with alcohol use disorder rates)

›Mean age at diagnosis: late 40s to 60s in alcohol-related cases

›Non-alcohol KS cases increasing with bariatric surgery prevalence

›Mortality and morbidity

›WE mortality if untreated: 10-20%

›KS: no significant progressive decline but no recovery of episodic memory

›Reduced life expectancy due to alcohol use disorder comorbidities

Pathophysiology

›Thiamine (vitamin B1) deficiency mechanism

›Thiamine pyrophosphate required for three key enzymes

›Pyruvate dehydrogenase: aerobic glucose metabolism

›Alpha-ketoglutarate dehydrogenase: Krebs cycle function

›Transketolase: pentose phosphate pathway

›Deficiency causes impaired oxidative metabolism in high-energy demand brain regions

›Glutamatergic excitotoxicity results from energy failure

›Selective vulnerability of diencephalic and brainstem structures

›Neuroanatomic basis of KS amnesia

›Papez circuit disruption: thalamus, hypothalamus, mammillary bodies, fornix

›Medial dorsal thalamic nucleus injury most consistently linked to amnesia

›Mammillary body atrophy: consistent structural marker on imaging

›Hippocampal involvement contributes but is not the primary lesion

›WE to KS transition

›Acute phase: edema, petechial hemorrhages in diencephalic regions

›Chronic phase: gliosis, neuronal loss, tissue atrophy

›Structural and metabolic alterations of Papez circuit persist over time — basis for irreversibility

›Neither significant recovery nor progressive neurodegenerative decline observed

›Cognitive phenotype

›Disproportionate amnesia relative to other cognitive functions

›Anterograde amnesia: failure to encode new episodic memories

›Retrograde amnesia: temporal gradient with remote memories better preserved

›Preserved implicit and procedural memory: exploit for rehabilitation

›Confabulation: often prominent early, diminishes over months to years

›Recent evidence: cognitive phenotype more variable than classically described in some patients

Therapeutic Considerations

›Thiamine pharmacology

›Thiamine half-life: short (96 minutes); parenteral dosing three times daily required

›Oral bioavailability: poor and erratic in alcohol use disorder due to mucosal transport saturation

›High-dose parenteral strategy supports adequate CNS penetration

›Anaphylaxis rare but reported: infuse over 30 minutes

›Glucose-thiamine interaction

›Carbohydrate metabolism depletes thiamine via cofactor consumption

›IV dextrose without thiamine precipitates acute WE in deficient patients

›Clinical protocol: thiamine before all glucose-containing fluids in at-risk patients

›Magnesium-thiamine interaction

›Magnesium required for thiamine pyrophosphate activation

›Hypomagnesemia renders thiamine replacement ineffective

›Concurrent magnesium repletion is mandatory for response

›Evidence base for high-dose thiamine

›Growing evidence supporting 500 mg IV TID over traditional 100-200 mg dosing

›No established upper safe limit; high doses better tolerated than undertreated WE

›JAMA Internal Medicine 2025 clinical commentary advocates earlier high-dose thiamine

›Prognosis of established KS

›Thiamine treatment does not reverse established KS amnesia

›Cognitive profile remains stable without progressive decline

›Implicit learning preserved — basis for errorless learning rehabilitation

›Confabulation typically diminishes; amnesia is permanent

›Alcohol abstinence prevents further brain injury and optimizes potential recovery

11Patient Discharge Instructions/pdi31

copy discharge instructions

›Discharge instructions for Korsakoff syndrome and Wernicke encephalopathy

›Your diagnosis and condition

›You have Korsakoff syndrome, a brain condition caused by severe vitamin B1 (thiamine) deficiency

›This condition causes significant memory problems that are largely permanent

›It often develops after a more acute brain episode called Wernicke encephalopathy

›Your medications — take these every day without stopping

›Thiamine (vitamin B1): take 100 mg by mouth every day indefinitely

›Do not stop taking thiamine without speaking to your doctor

›Take all other prescribed medications as directed

›Alcohol and diet

›Stop drinking alcohol completely — continued alcohol use causes more brain damage

›Eat a balanced diet with thiamine-rich foods: whole grains, meat, legumes, and fortified cereals

›Do not take large amounts of carbohydrates without thiamine supplementation

›If you feel nauseous or cannot eat, contact your doctor immediately

›Follow-up appointments

›Neurology appointment within 2-4 weeks of discharge — do not miss this

›Memory and cognitive testing appointment within 4-6 weeks

›Addiction medicine or counseling appointment for alcohol cessation support

›Living with memory problems

›Use a calendar, alarms, and written notes to help remember appointments and tasks

›A structured daily routine helps your brain function better

›Let family members or caregivers help you keep track of medications and appointments

›Your memory for skills and routines is better preserved than for new facts — use this

›Return to the emergency department immediately for

›Sudden new confusion or significant worsening of mental status

›Seizures or loss of consciousness

›New double vision, eye movement problems, or vision loss

12References/r55

Guidelines and key sources

›Sinha S, Kataria A, Kolla BP, Thusius N, Loukianova LL

›Wernicke Encephalopathy-Clinical Pearls

›Mayo Clinic Proceedings 2019

›PMID 31171116

›Day E, Bentham PW, Callaghan R, Kuruvilla T, George S

›Thiamine for Prevention and Treatment of Wernicke-Korsakoff Syndrome in People Who Abuse Alcohol

›Cochrane Database of Systematic Reviews 2013

›DOI 10.1002/14651858.CD004033.pub3

›Sechi G, Serra A

›Wernicke Encephalopathy: New Clinical Settings and Recent Advances in Diagnosis and Management

›The Lancet Neurology 2007

›PMID 17434099

›Oudman E, Wijnia JW, Oey MJ, van Dam M, Postma A

›Wernicke-Korsakoff Syndrome Despite No Alcohol Abuse: A Summary of Systematic Reports

›Journal of the Neurological Sciences 2021

›PMID 34000679

›Arts NJ, Walvoort SJ, Kessels RP

›Korsakoff Syndrome: A Critical Review

›Neuropsychiatric Disease and Treatment 2017

›PMID 29225466

›Scalzo SJ, Bowden SC

›Over a Century of Study and Still Misunderstood: Recognizing the Spectrum of Acute and Chronic Wernicke-Korsakoff Syndrome

›Journal of Clinical Medicine 2023

›PMID 37959345

Neuroimaging references

›Jung YC, Chanraud S, Sullivan EV

›Neuroimaging of Wernicke Encephalopathy and Korsakoff Syndrome

Evidence & Review

Evidence & Review