Metabolic Encephalopathies

Metabolic encephalopathies represent disorders of brain function that lack a structural source. The terminology is too limited to encompass the scope of the cognitive difficulties encountered in the intensive care units. Delirium is a description of the cognitive disturbances often encountered with a developing encephalopathy. This disorder is characterized by an acute disturbance in consciousness that cannot be accounted for by a general medical condition or an underlying dementia. Septic encephalopathy refers to the encephalopathy encountered in the acutely ill or septic patient. Its presence has direct impact or morbidity and mortality. The encephalopathy is believed to be mediated by inflammatory mediators which gain access to the brain through a damaged blood-brain barrier. Neuronal and hormonal transmission is subsequently disturbed. Hepatic encephalopathy refers to the neuropsychiatric abnormality that develops with acute and chronic liver failure. It is believed to correlate with serum ammonia levels through production of intracellular glutamine. Treatment focuses on lowering ammonia levels and instituting measures to decrease cerebral edema.