Metabolic and Diffuse Encephalopathies: Disruption of the Internal Milieu
Chapter 5 examines the broad range of metabolic causes of unconsciousness and the specific treatments they require. The main feature distinguishing diffuse or metabolic impairment of consciousness is that it is normally not associated with focal neurological findings that would suggest a structural lesion of the brain. However, there are some features of the neurological examination of patients with metabolic encephalopathies that can help to pinpoint the cause of the disturbance. In addition, there are some findings on examination that may appear to be due to focal lesions, but which can be due to diffuse or metabolic disease. The chapter first examines the diagnostic features of metabolic encephalopathies. It then looks at the internal metabolic milieu in which the brain functions normally. It also considers specific types of metabolic and diffuse disturbances of that internal milieu that can cause encephalopathy. Finally, it considers various endogenous and exogenous toxins that produce toxic encephalopathies.