Wernicke encephalopathy

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Wernicke encephalopathy is "an acute neurological disorder characterized by the triad of ophthalmoplegia, ataxia, and disturbances of mental activity or consciousness. Eye movement abnormalities include nystagmus, external rectus palsies, and reduced conjugate gaze. Thiamine deficiency and chronic alcoholism are associated conditions. Pathologic features include periventricular petechial hemorrhages and neuropil breakdown in the diencephalon and brainstem. Chronic thiamine deficiency may lead to Korsakoff syndrome.[1]

This disorder was first described in 1881 by Carl Wernicke based on three untreated cases.[2]

Cause/etiology

The most common causes of Wernicke encephalopathy are alcoholism and a thiamine deficiency. Many conditions can cause a thiamine deficiency, such as hyperemesis gravidarum (vomiting during pregnancy),[3] dialysis,[4] and malnourished states in end-stage cancer, intractable vomiting, and extended courses of intravenous fluids with no other source of nutrition.[5]

Biochemistry

Thiamine is converted by the enzyme thiamine pyrophosphokinase to thiamine pyrophosphate. Thiamine pyrophosphate is a coenzyme for dehydrogenase enzymes in aerobic respiration, and the enzyme transketolase in the pentose phosphate pathway.[6]


Diagnosis

History and physical examination

Most patients will have absent nystagmus to cold caloric testing.[7]

Blood tests

Thiamine level

The concentration of thiamine (or more specifically thiamine pyrophosphate) can be measured in whole blood by high performance liquid chromatography (HPLC). Thiamine pyrophosphate may also be low in elderly and cause subtle peripheral neuropathy.[8]

Erythrocyte thiamine transketolase activity

Thiamine transketolase functional assay in whole blood may be used.[9], However, it can also be falsely low in other conditions.


MRI

The MRI may show enhancement of mamillary bodies with gadolinium suggesting reversible cytotoxic edema in 58% of patients.[10]

Treatment

The treatment is thiamine, thiamine tetrahydrofurfuryldisulphide (TTFD). Outcomes are worse if treatment is delayed.[9]

References

  1. National Library of Medicine. Wernicke Encephalopathy. Retrieved on 2008-01-01.
  2. Thomson AD, Cook CC, Guerrini I, Sheedy D, Harper C, Marshall EJ (2007). "Wernicke's encephalopathy revisited * Translation of the case history section of the original manuscript by Carl Wernicke 'Lehrbuch der Gehirnkrankheiten fur Aerzte and Studirende' (1881) with a commentary". Alcohol Alcohol. DOI:10.1093/alcalc/agm144. PMID 18056751. Research Blogging.
  3. Chiossi G, Neri I, Cavazzuti M, Basso G, Facchinetti F (2006). "Hyperemesis gravidarum complicated by Wernicke encephalopathy: background, case report, and review of the literature". Obstet Gynecol Surv 61 (4): 255–68. DOI:10.1097/01.ogx.0000206336.08794.65. PMID 16551377. Research Blogging.
  4. Hung SC, Hung SH, Tarng DC, Yang WC, Chen TW, Huang TP (2001). "Thiamine deficiency and unexplained encephalopathy in hemodialysis and peritoneal dialysis patients". Am. J. Kidney Dis. 38 (5): 941–7. PMID 11684545[e]
  5. Ogershok PR, Rahman A, Nestor S, Brick J (2002). "Wernicke encephalopathy in nonalcoholic patients". Am. J. Med. Sci. 323 (2): 107–11. PMID 11863078[e]
  6. Stryer, Lubert; Berg, Jeremy Mark; Tymoczko, John L. (2002). Biochemistry. San Francisco: W.H. Freeman. ISBN 0-7167-3051-0.  http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=stryer [Full text]
  7. Ghez C (1969). "Vestibular paresis: a clinical feature of Wernicke's disease". J. Neurol. Neurosurg. Psychiatr. 32 (2): 134–9. PMID 5305749[e]
  8. Wilkinson TJ, Hanger HC, George PM, Sainsbury R (2000). "Is thiamine deficiency in elderly people related to age or co-morbidity?". Age Ageing 29 (2): 111–6. PMID 10791444[e]
  9. 9.0 9.1 Leigh D, McBurney A, McIlwain H (1981). "Erythrocyte transketolase activity in the Wernicke-Korsakoff syndrome". Br J Psychiatry 139: 153–6. PMID 7306754[e]
  10. Zuccoli G, Gallucci M, Capellades J, et al (2007). "Wernicke encephalopathy: MR findings at clinical presentation in twenty-six alcoholic and nonalcoholic patients". AJNR Am J Neuroradiol 28 (7): 1328–31. DOI:10.3174/ajnr.A0544. PMID 17698536. Research Blogging.