Wernicke s encephalopathy

Thiamin deficiency can result in three distinct syndromes a chronic peripheral neuritis, beriberi, which may or may not be associated with heart ilure and edema acute pernicious (fulminating) beriberi (shoshin beriberi), in which heart failure and metabolic abnormalities predominate, without peripheral neuritis and Wernicke s encephalopathy with KorsakofPs psychosis, which is associated especially with alcohol and dmg abuse. The central role of thiamin diphosphate in... 

Administer before glucose administration to prevent precipitation of Wernicke s encephalopathy... 

Wernicke s encephalopathy A neurological condition characterised by visual disturbances, motor dysfunction and confusion which, like Korsakoff s syndrome, is commonly associated with long-term alcohol misuse. 

Hepatic encephalopathy Hyperbilirubinemia Hypocalcemia Hypercalcemia Hyperparathyroidism Hypoparathyroidism Thiamine deficiency (Wernicke s) encephalopathy Diabetic ketoacidosis Nonketotic hyperosmolar coma Phosphate depletion Hypoglycemia Hypoxemia Hypercapnia... 

Thiamine deficiency results in early decreases in activity of the mitochondrial enzyme a-ketoglutarate dehydrogenase in brain. Wernicke s encephalopathy, also known as the Wernicke-Korsakoff syndrome is a neuropsychiatric disorder characterized by ophthalmoplegia, ataxia and memory loss. Wernicke s encephalopathy is encountered in chronic alcoholism, in patients with HIV-AIDS and in other disorders associated with grossly impaired nutritional status. The condition results from thiamine deficiency. 

Neuropathologic studies in animals with experimental thiamine deficiency consistently show early damage to glial cells rather than neurons. Studies in human patients with Wernicke s encephalopathy likewise show changes in astroglia, together with microglial proliferation, which is... 

Pannunzio, P., Hazell, A. S., Pannunzio, M., Rama Rao, K. V. and Butterworth, R. F. Thiamine deficiency results in metabolic acidosis and energy failure in cerebellar granule cells an in vitro model for the study of cell death mechanisms in Wernicke s encephalopathy. /. Neurosci. Res. 62 286-292, 2000. 

Inadequate nutrition and conditions which are complicated by malabsorption may lead to thiamine deficiency. Beriberi, a diet-deficiency disease, is especially prevalent in those parts of the East where the diet consists mainly of polished rice. The disease is characterized by neuritis but may also lead to serious heart failure. Recovery is prompt when adequate amounts of vitamin B1 are restored to the diet. Severe deficiency as can occur in alcoholics may lead to Wernicke s encephalopathy, often accompanied by Korsakoff s syndrome. Care should be taken with intravenous substitution with thiamine in these cases to prevent serious complications like vascular collapse with hypotension, respiratory distress or an-gioedema. 

Where patients are at risk of Wernicke s encephalopathy - for example, because of chronic alcohol abuse, hyperemesis gravidarum, or malnutrition - they should be given thiamine. In many countries no intravenous preparation of thiamine alone is available, and the compound preparations that are available are prone to cause anaphylactoid reactions, so they should be given by slow infusion, and with adequate facilities for resuscitation. A high potency preparation (Pabrinex ) that contains thiamine 250 mg in 10 ml with ascorbic acid, nicotinamide, pyridoxine and riboflavin, can be given by intravenous infusion over 10 min. 

A variety of pathological problems involving the CNS have been described in chronic alcoholics, the main ones being Wernicke s encephalopathy and Korsakoff s psychosis Brain damage from chronic ethanol consumption can be especially severe in the elderly and may accelerate aging. 

Wernicke s encephalopathy IM, IV 100 mg IM or slow IV infusion for 3 days, up to 1,000 mg maybe necessary in the first 12 hr, then 50-100 mg IM daily until adequate... 

The spectrum of cognitive deficits associated with chronic alcohol use extends to the extreme of Wernicke s encephalopathy and Korsakoff s psychosis. Wernicke s encephalopathy is an acute neurologic syndrome caused by thiamine deficiency. Symptoms include mental confusion, ophthalmoplegia, and ataxia. Many of these symptoms reverse with administration of thiamine however about 50% of patients are left with some degree of ataxia. Left untreated, Wernicke s encephalopathy can progress to stupor, coma, and death. Approximately 80% to 90% of alcoholics treated for Wernicke s encephalopathy are left with Korsakoff s psychosis, a syndrome of impaired learning and recent memory produced by lesions of the medial dorsal nuclei of the thalamus. 

Ethanol-related cognitive deficits in the absence of Wernicke s encephalopathy also improve with extended abstinence. Most functional neuroimaging studies of abstinent alcoholics have shown decreases in both cerebral glucose metabolism and blood flow, with the decreases being greatest in the frontal lobes (Netrakom et ah, 1999). 

Beriberi (characterized by nerve involvement - peripheral neuritis), Wernicke s encephalopathy (characterized by ophthalmoplegia, polyneuritis and mental disorientation). 

It is indicated in wet beriberi, dry beriberi, Wernicke s encephalopathy, prophylaxis of thiamine deficiency, hyperemesis gravidarum, Korsakoff s syndrome, chronic alcoholics, multiple neuritis, toxic and confusional states, delirium tremens and anorexia nervosa. 

The Wernicke-Korsakofi syndrome consists of both an acute (i.e., Wernicke s encephalopathy) and a chronic phase (i.e., Korsakoff s psychosis). The acute encephalopathy may be precipitated or worsened by carbohydrates (including intravenous glucose) unless thiamine is also replenished before or during administration. Wernicke s encephalopathy may first be manifested by the following ... 

Thiamine is given for alcohol-induced liver toxicity (to prevent Wernicke s encephalopathy). 

Acute infantile beriberi in infants breast-fed by deficient mothers may involve high-output cardiac failure, as in shoshin beriberi, as well as signs of central nervous system involvement similar to those seen in Wernicke s encephalopathy (Section 6.4.4). 

Initially, there is a confused state, Korsakoff s psychosis, that is characterized by confabulation and loss of recent memory, although memory for past events may be unimpaired. Later, clear neurological signs develop - Wernicke s encephalopathy. This is characterized by nystagmus and extraocular palsy. Postmortem examination shows hemorrhagic lesions in the thalamus, pontine tegmentum, and mammillary body, with severe damage to astrocytes, neuronal dendrites, and myelin sheaths. 

Wernicke s encephalopathy may be more common than is believed on clinical grounds. Harper (1979) reported that 1.7% ofall postmortem examinations in Western Australia over a 4-year period showed clear anatomical evidence of the disease, yet only 13% of the patients had been diagnosed as suffering from the condition. Other studies have similarly shown that only 10% to 20% of cases confirmed by postmortem examination had been diagnosed on clinical grounds (Zubaran et al., 1997). There appears to have been a reduction in the... 

Peters R (1963) Biochemical Lesions and Lethal Synthesis. Oxford Pergamon Press. Reuker JB, Girard DE, and Cooney TG (1985) Wernicke s encephalopathy. New England Journal of Medicine312, 1035-8. 

Harper C (1979) Wernicke s encephalopathy a more common disease than realised. A neuTopathologicaistudyof51ca.ses.JoumalofNeurologyNeurosurgeryandPsychiatry 42,226-31. 

Hazell AS, Todd KG, and Butterworth RE (1998) Mechanisms of neuronal cell death in Wernicke s encephalopathy. Metabolic Brain Diseases 13, 97-122. 

HerouxM and Butterworth RF (1995) Regional alterations of thiamine phosphate esters and of thiamine diphosphate-dependent enzymes in relation to function in experimental Wernicke s encephalopathy. Neurochemistry Research 20,87-93. 

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