Wernicke-Korsakoff’s Syndrome (WKS)
Wernicke’s Encephalopathy (WE) –
Wernicke’s encephalopathy is an acute potentially reversible neuropsychiatric disorder caused by a deficiency in or depletion of thiamine of which chronic alcohol use is one cause. Other causes include gastric bypass surgery, gastric and colon cancer, hyperemesis gravidarum, long-term parenteral feeding and poor nutrition.
Wernicke’s encephalopathy is a medical emergency. Untreated, it leads to death in up to 20% of cases.
Thiamine deficiency in alcohol dependence occurs because of poor absorption of thiamine from the GI tract, impaired thiamine storage and reduced thiamine phosphorylation in the brain reducing the amount of active thiamine in the brain. (Thiamine Pyrophosphate)
Triad consists of
- Oculomotor abnormalities – lateral rectus palsy, nystagmus, ophthalmoplegia
- Cerebellar dysfunction – Ataxia
- Altered mental state – confusion
Clinical Pearl – Only 20% of patients may show the full triad in clinical practice.
The European Federation of Neurological Societies (EFNS) recommends a presence of 2 of the following four signs as evidence of Wernicke’s encephalopathy [EFNS] –
- Dietary deficiency
- Oculomotor abnormality
- Mild memory impairment
- Altered mental status
Treatment of acute WE –
- Thiamine 500 mg IV tds for 2-3 days and 250 mg daily for next 3-5 days
- Thiamine 100 mg PO tds for rest of hospital stay
- Replace Mg
- Replace fluid and electrolyte losses
Clinicians suspecting Wernicke’s encephalopathy in a patient should treat it as an emergency and provide optimum intravenous treatment in order to avoid permanent brain damage. (BNF)
Prophylactic treatment for patients at risk of WE – Thiamine 200-300mg IM daily for 3-5 days.
Undiagnosed and untreated WE can lead to Korsakoff’s syndrome in 80% of cases.
Clinical features :
First described by Victor (1971)
An abnormal mental state in which memory and learning are affected out of all proportion to other cognitive functions in an otherwise alert and responsive patient
- Anterograde amnesia (impaired ability to acquire new episodic memories)
- Retrograde amnesia
- Lack of insight
- Disorientation in time and place
- Executive dysfunction
- Sequelae of WE
MRI findings in WKS-
- Mamillary body atrophy
- Neuronal loss in the anterior principal and mediodorsal nuclei of the thalamus and the basal forebrain
The most obvious neuroradiological sign of acute WE, regardless of etiology, is bilateral hyperintensity on late-echo MRI, generally occurring in gray matter tissue of the mammillary bodies, anterior and medial nuclei of the thalamus, periventricular gray matter, inferior and superior colliculi.
Read more about the effects of Alcohol on the Brain here.