Metabolic Encephalopathy - Part II

Normal neurologic function requires a constantly balanced environment of electrolytes.  Normal hepatic and renal function is critical in maintaining this balance while removing toxins, maintaining a physiologic pH and regulating the excretion of electrolytes.  Nutritional intake provides essential nutrients but deficiencies can lead to characteristic syndromes such as Wernicke's encephalopathy and pellagra and exposure to neurotoxic substances such as heavy metals can lead to encephalopathy.  Thyroid and adrenal dysfunction are common endocrine causes of encephalopathy and symptoms can often improve rapidly with treatment.  A subset of idiopathic encephalopathy is increasingly being recognized as having an autoimmune basis, often presenting as a paraneoplastic process, and having a constellation of symptoms which can aide in the diagnosis.  Timely recognition and treatment of the autoantibodies which target neural structures, with immunosuppressive therapy, can improve outcome in these patients.   This review contains 4 figures, 3 tables, and 42 references. Key words: osmotic demyelination syndrome,hepatic encephalopathy, renal failure, triphasic waves, dialysis disequilibrium syndrome, Wernicke encephalopathy, Korsakoff syndrome, myxedema coma, Hashimoto encephalopathy