Neurologic Complications in Critically Ill Patients

Neurologic complications of sepsis are related primarily to inflammatory mediators that gain access to both the central and peripheral nervous systems. These mediators have significant effects on oxygen delivery and utilization at the level of the microvasculature endothelium and mitochondria. The resultant inhibition can lead to neurologic dysfunction and death through a variety of mechanisms including ischemia, hypoxia, and decreased axonal transport of nutrients. Both the central and peripheral manifestations of inflammatory mediators have a profound effect on long-term cognition and potential for rehabilitation. The encephalopathy associated with sepsis occurs in many critically ill patients. Although a diagnosis of exclusion, its presence can be detected on examination and EEG monitoring and portends a worse outcome than otherwise. Critical illness neuropathy and myopathy represent a spectrum of diseases that result from either the effects of inflammatory mediators or treatments initiated to treat critically ill patients. The extent of the neuropathy correlates with the duration and severity of the underlying illness. This chapter explores the diagnosis, evaluation, pathogenesis, and treatment strategies for these various entities.