Wernicke Encephalopathy and Korsakoff Syndrome
NICE Clinical guideline [CG100] Alcohol-use disorders: diagnosis and management of physical complications. Last updated: Apr 2017.
Background information added accordingly.
Date: 12/11/25
Wernicke Encephalopathy
Definition
Wernicke encephalopathy is an acute neuropsychiatric syndrome resulting from thiamine (vitamin B1) deficiency
Aetiology
Wernicke’s encephalopathy is caused by thiamine (vitamin B1 deficiency)
Causes of thiamine deficiency: [Ref]
- Chronic alcoholism (due to reduced dietary intake, reduced GI absorption and impaired thiamine utilisation by the body) – most common
- Gastrointestinal malabsorption
- Certain surgeries (e.g. bariatric procedures, bowel resection)
- Malnutrition
- Hyperemesis gravidarum
- Prolonged fasting
Clinical Features
The classic triad: [Ref]
- Altered mental status (confusion, apathy, impaired awareness) – most common
- Ocular abnormalities (nystagmus, ophthalmoplegia, diplopia)
- Ataxia (wide-based gait with small steps)
Less common / atypical features: [Ref]
- Tachycardia, hypotension
- Hypothermia
- Bilateral visual disturbances, papilloedema
- Seizures
- Hearing loss
- Dysphagia
NB All three features are present in only a minority of cases. Therefore, Wernicke encephalopathy should be suspected in any patient with a history of chronic heavy alcohol use who exhibits at least one of the classic triad features.
Investigation and Diagnosis
Wernicke encephalopathy is typically a clinical diagnosis.
Investigation findings (not routinely performed): [Ref]
- Biochemical changes
- ↓ Serum thiamine level
- ↑ Serum lactate
- Best test: MRI
- Typical findings: periventricular haemorrhage and/or mamillary body atrophy
- Bilateral symmetrical hyperintensities in the medial thalamus, mamillary bodies, periaqueductal grey matter, midbrain, 4th ventricle
Prevention
Offer prophylactic oral thiamine to harmful or dependent drinkers if:
- Malnourished or at risk, or
- Decompensated liver disease, or
- In acute withdrawal, or
- Before and during a planned medically assisted alcohol withdrawal
IV thiamine can be offered if the patient is in the emergency department or admitted to hospital.
When IV thiamine is indicated in the context of Wernicke’s encephalopathy, IV Pabrinex is usually used rather than just thiamine alone and is routinely recommended in trust guidelines.
IV Pabrinex contains vitamin B1 (thiamine), B2, B6, vitamin C, nicotinamide, and glucose.
IV thiamine (usually Pabrinex) should be given before or concomitantly with glucose (dextrose) in patients with, or at risk for Wernicke encephalopathy, as it may precipitate or worsen Wernicke encephalopathy.
This is because vitamin B1 (thiamine) is an essential cofactor for glucose metabolism. When glucose is given to someone who is already thiamine-deficient, the increased glucose metabolism will rapidly consume the body’s already depleted thiamine stores.
However, the latest American Society of Addiction Medicine guideline notes that, while traditional teaching emphasised thiamine before glucose, there is insufficient evidence to mandate this sequence. Such that glucose administration should not be delayed if urgently needed (i.e. if patient is hypoglycaemic), thiamine and glucose may be given together. [Ref]
Management
Offer IV high-dose thiamine for at least 5 days (or until clinical improvement plateaus) → followed by oral thiamine
When IV thiamine is indicated in the context of Wernicke’s encephalopathy, IV Pabrinex is usually used rather than just thiamine alone and is routinely recommended in trust guidelines.
IV Pabrinex contains vitamin B1 (thiamine), B2, B6, vitamin C, nicotinamide, and glucose.
IV thiamine (usually Pabrinex) should be given before or concomitantly with glucose (dextrose) in patients with, or at risk for Wernicke encephalopathy, as it may precipitate or worsen Wernicke encephalopathy.
This is because vitamin B1 (thiamine) is an essential cofactor for glucose metabolism. When glucose is given to someone who is already thiamine-deficient, the increased glucose metabolism will rapidly consume the body’s already depleted thiamine stores.
However, the latest American Society of Addiction Medicine guideline notes that, while traditional teaching emphasised thiamine before glucose, there is insufficient evidence to mandate this sequence. Such that glucose administration should not be delayed if urgently needed (i.e. if patient is hypoglycaemic), thiamine and glucose may be given together. [Ref]
Korsakoff Syndrome
Definition
Korsakoff syndrome is a chronic, irreversible neuropsychiatric disorder that arises from untreated / inadequately treated Wernicke encephalopathy
Clinical Features
Korsakoff syndrome is characterised by the following:
- Severe anterograde amnesia (inability to form new memories) (patients often cannot recall events from the previous half hour and have difficulty learning new information)
- Confabulation (fabrication of stories to fill memory gaps)
- Disorientation to time
- Executive dysfunction (e.g. impaired planning and problem-solving skills)
- Emotional / behavioural changes (e.g. apathy, bland affect, mild euphoria)
- Long-term memory, cognition and motor skills are usually preserved
Note that Korsakoff syndrome is generally considered irreversible
Investigation and Diagnosis
Korsakoff syndrome is typically a clinical diagnosis (same as Wernicke encephalopathy)
Investigation findings (not routinely performed) (same as Wernicke encephalopathy): [Ref]
- Biochemical changes
- ↓ Serum thiamine level
- ↑ Serum lactate
- Best test: MRI
- Typical findings: periventricular haemorrhage and/or mamillary body atrophy
- Bilateral symmetrical hyperintensities in the medial thalamus, mamillary bodies, periaqueductal grey matter, midbrain, 4th ventricle
Management
There are no official NICE guidelines on Korsakoff syndrome, management principles are as following:
- Supportive care (e.g. fluid and electrolyte replacement), and
- IV high-dose thiamine (it does NOT treat or reverse Korsakoff syndrome but can prevent or slow down progression)