Metabolic encephalopathies

Metabolic encephalopathies, usually multifactorial in origin, may be important complications of many diseases of patients treated in a critical care unit. In many cases these complications arise from more than one cause. Neurological signs of metabolic encephalopathies, ancillary tests and differential diagnosis, etiology and pathophysiology are discussed. In this context major single causes for metabolic encephalopathies are referred to. Metabolic encephalopathies as diseases per se (e. g. Wernicke's encephalopathy) and encephalopathies as consequences of deteriorating known diseases (e. g. renal or hepatic diseases) and encephalopathies as complications in patients treated with other diseases in the ICU have to be differentiated. Encephalopathies are known to be the most common complication of a large group of diseases treated in the ICU; on the other hand, manifestation of metabolic encephalopathy can be taken as a warning of deterioration or beginning organ dysfunction. So it would be misleading so far to reduce the clinical concept of metabolic encephalopathies in ICH to septic encephalopathy only.