Wernicke-Korsakoff Syndrome

Wernicke-Korsakoff Syndrome (WKS) is a medical condition that combines Wernicke's encephalopathy (WE) and Korsakoff's syndrome. It primarily affects the brain and is often associated with chronic alcohol abuse, leading to a deficiency in thiamine (vitamin B1).

This syndrome can lead to severe neurological and cognitive impairments if left untreated.

Signs and Symptoms

Wernicke Encephalopathy

WE is characterised by a classic triad of symptoms: ocular disturbances (ophthalmoplegia), changes in mental state (confusion), and unsteady stance and gait (ataxia). These symptoms arise due to a deficiency of thiamine, an essential coenzyme. Additional symptoms can include stupor, hypotension, tachycardia, hypothermia, seizures, and progressive hearing loss. If untreated, WE can lead to coma or death.

Korsakoff Syndrome

Korsakoff syndrome, as classified in the DSM-5, is marked by prominent amnesia, rapid forgetting, and difficulty learning. These symptoms can occur with thiamine-deficient encephalopathy due to conditions beyond alcohol abuse, such as malnutrition or gastrectomy.

Cognitive Effects

Cognitive impairments in WKS can include insomnia, anxiety, confusion, confabulation, hallucinations, disrupted speech, and difficulty focusing. A study by Brand et al. (2003) showed that WKS patients performed poorly on neuropsychological tests, particularly on cognitive estimation tasks.

Memory Deficits

WKS patients exhibit both retrograde and anterograde amnesia, with retrograde amnesia extending back 20-30 years. The memory impairment is linked to damage in the mammillary bodies and thalamic regions. Despite these deficits, non-declarative memory functions such as perceptual priming remain intact.

Confabulation

Confabulation is common in WKS, with spontaneous confabulations being more frequent. This may be due to impaired source memory or executive dysfunction, leading to incorrect memories or responses.

Causes

WKS is caused by a severe deficiency of thiamine. Chronic alcohol use, which disrupts thiamine uptake, storage, and transformation, is the primary cause. Other causes include prolonged IV therapy without thiamine supplementation, gastric surgery, and conditions leading to malnutrition.

Alcohol-Thiamine Interactions

Ethanol interferes with thiamine absorption in the gastrointestinal tract and its storage in the liver. Animal studies have shown that alcohol exposure accelerates the onset of neurological problems due to thiamine deficiency.

Pathophysiology

Thiamine is very important for energy production in the brain. Prolonged alcohol consumption impairs thiamine absorption, leading to inadequate ATP production and neuronal death. Brain regions affected include the mammillary bodies, thalamus, periaqueductal grey, cerebellum, and frontal lobe.

Diagnosis

Diagnosis is based on clinical presentation and sometimes confirmed by neuropsychological assessment. WE typically presents with ataxia and nystagmus, while Korsakoff's psychosis involves amnesia and confabulation. MRI imaging can show characteristic brain changes, such as degeneration of the mammillary bodies.

Prevention

Preventing WKS involves limiting alcohol intake and ensuring proper nutrition with adequate thiamine intake. Thiamine supplementation can prevent the progression of WE to WKS if administered promptly.

Treatment

Immediate administration of thiamine is very important in suspected WE cases. A typical dose is 500 mg of thiamine hydrochloride via infusion for two to three days, followed by a reduced dose if improvement is observed. Early treatment can prevent or mitigate the severity of WKS but may not fully reverse existing deficits.

Epidemiology

WKS is more common in men, especially those aged 55-65, and has a higher prevalence among the homeless, older individuals, and psychiatric inpatients. The prevalence does not correlate with alcohol consumption per capita, as evidenced by varying rates in different countries.

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Self-assessment MCQs (single best answer)

What are the primary conditions that combine to form Wernicke-Korsakoff Syndrome (WKS)?

Which vitamin deficiency is primarily associated with Wernicke-Korsakoff Syndrome?

What is one of the classic symptoms of Wernicke's encephalopathy?

Korsakoff syndrome is primarily characterised by which type of cognitive impairment?

Which brain regions are typically affected in Wernicke-Korsakoff Syndrome?

What is a common cause of Wernicke-Korsakoff Syndrome?

What type of imaging is often used to diagnose brain changes associated with Wernicke-Korsakoff Syndrome?

Which symptom is more commonly associated with Korsakoff syndrome than with Wernicke's encephalopathy?

What is the immediate treatment for suspected Wernicke's encephalopathy?

Which population group is more commonly affected by Wernicke-Korsakoff Syndrome?