<aside> 🍻 Wernicke's COAT:

Confusion,

Oculomotor dysfunction,

Ataxia

Thiamine administration

Korsakoff's CART: 😵‍💫

Confabulation,

Anterograde and

Retrograde amnesia

altered Temper

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<aside> 😵‍💫 Oculomotor dysfunction, ataxia, and confusion form the triad of Wernicke syndrome.  Most of these symptoms usually resolve after thiamine administration. Korsakoff syndrome is a chronic and irreversible complication of Wernicke encephalopathy, the hallmarks of which are permanent memory loss and confabulation.

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Vitamin B1 (Thiamine) Deficiency — Beriberi, Wernicke Korsakoff

• Wernicke-Korsakoff syndrome is caused by thiamine (B1) deficiency, which impairs the function of α-ketoglutarate dehydrogenase, pyruvate dehydrogenase, and transketolase.

  

• Refers to two entities

  • Wernicke encephalopathy
    • acute
    • potentially reversible
    • involves mammillary bodies
  • Korsakoff syndrome
    • chronic
    • irreversible
    • involves mammillary bodies, thalamic regions, and corpus callosum

• Diagnosis & Clinical features

  • Clinical diagnosis that does not require imaging studies
  • Wernicke's encephalopathy
    • encephalopathy (disorientation, indifference, inattentiveness)
    • ophthalmoplegia
    • gait ataxia
  • Korsakoff's psychosis
    • memory loss (anterograde and retrograde)
    • confabulation
    • personality change

• Thiamine must be administered with glucose to avoid precipitating the onset of Wernicke encephalopathy

• Prescribe thiamine supplementation to patients at risk

• Chronic thiamine (vitamin B1) deficiency impairs glucose use, particularly in mammillary bodies, as seen in Wernicke encephalopathy.
  • This occurs due to decreased activity of the enzymes that use thiamine as a cofactor (eg, transketolase).  Low erythrocyte transketolase activity that increases after the addition of thiamine pyrophosphate is diagnostic.

Wernicke encephalopathy, a condition caused by chronic thiamine (vitamin B1) deficiency. The clinical features and course of Wernicke encephalopathy are as follows:

• Oculomotor dysfunction (eg, nystagmus, lateral rectus palsy) occurs due to impairment of the oculomotor nuclei. It is rapidly reversible with thiamine administration.

• Ataxia is caused by damage to the cerebellar cortex and vestibular nuclei. Unlike oculomotor function, ataxia takes longer to resolve, and some patients may have permanent symptoms.

• Encephalopathy, ranging from decreased attention span to disorientation and stupor, can occur, and impaired memory/learning may be apparent. Acute mental status changes respond well to treatment, but memory and learning abnormalities usually persist, as a condition known as Korsakoff syndrome.

• The mammillary bodies are nearly universally affected and demonstrate focal hemorrhage or atrophy on imaging; Anterior pillars of the fornix

  • foci of hemorrhage and necrosis in the mammillary bodies and periaqueductal gray matter

  

Korsakoff syndrome is associated with damage to the anterior and dorsomedial thalamic nuclei.  This results in chronic, irreversible memory loss, both short-term retrograde (recent events) and anterograde (unable to form new memories) amnesia.  Patients with Korsakoff syndrome also often have a psychologic phenomenon called "confabulation"; when such patients are unsure of a fact, they subconsciously fill in the memory gap with a fabricated story that they believe to be true.

Thiamine should be administered immediately for suspected Wernicke encephalopathy because it decreases the risk for irreversible neurologic damage.

Sample case:

A 65-year-old man with a history of chronic alcohol use presents to his primary care clinic. Two years ago, he was hospitalized for acute confusion, vision loss, and unsteady gait, which resolved with thiamine repletion. Since discharge, he has continued to drink alcohol heavily and has developed progressive forgetfulness. He cannot recall recent events. When asked questions, he responds confidently with incorrect answers.

Sample case 2:

A 52-year-old man is brought to the emergency department after being found by police confused and lethargic in the park. The policemen report that the patient could not recall where he was or how he got there. Medical history is significant for multiple prior hospitalizations for acute pancreatitis. He also has scheduled visits with a psychiatrist for managing his depression and substance abuse. On physical examination, the patient was found to have horizontal nystagmus and a wide-based gait with short-spaced steps. The patient is started on appropriate medication and admitted to the medicine floor. He was re-evaluated after treatment implementation and currently does not appear confused. When asked how he got to the hospital, the patient says, "I remember leaving my wallet here and thought I should pick it up." On cognitive testing the patient is noted to have impairments in judgement, sequencing tasks, and memory. Which of the following enzymes was most likely impaired in this patient?

Answer: Transketolase