Pathophysiology of septic encephalopathy: A review

Objectives: Encephalopathy is a common complication of sepsis. This review describes the different pathologic mechanisms that may be involved in its e tiology. Data Sources: The studies described here were derived from the database Pub Med (http:\\www.nlm.nih.gov) and from references identified in the bibliogr aphies of pertinent articles and books. The citations are largely confined to English language articles between 1966 and 1998. Older publications were used if they were of historical significance. Study Selection: All investigations in which any aspect of septic encephalo pathy was reported were included. This selection encompasses clinical, anim al, and in vitro cell culture work. Data Extraction: The literature cited was published in peer-reviewed clinic al or basic science journals or in books. Data Synthesis: Contradictions between the results of published studies are discussed. Conclusions: The most immediate and serious complication of septic encephal opathy is impaired consciousness, for which the patient may require ventila tion. The etiology of septic encephalopathy involves reduced cerebral blood flow and oxygen extraction by the brain, cerebral edema, and disruption of the blood-brain barrier that may arise from the action of inflammatory med iators on the cerebrovascular endothelium, abnormal neurotransmitter compos ition of the reticular activating system, impaired astrocyte function, and neuronal degeneration. Currently, there is no treatment.