[Septic encephalopathy].

Abstract

Impaired mental function, from clouding of consciousness to deep coma is often seen in patients with systemic inflammation. Diagnosis of this syndrome which is called "septic encephalopathy" is dependent on exclusion of other causes. The underlying mechanisms have only been defined in parts. The appearance of cerebral symptoms during an infection increases mortality. Primary symptoms of septic encephalopathy appear early, before other septic organ manifestations become apparent. The most sensible parameter for diagnosis of septic encephalopathy in comatose patients or under sedation is the EEG. It shows general alterations which increase parallelly to the severity of septic encephalopathy. Septic encephalopathy has to be considered a multifactorial event. In an early stage of the development of septic encephalopathy, bacteremia induces overproduction of cytokines and other mediators. This causes metabolic dysregulation with effects on the cerebral protein-, glucose and neurotransmitter metabolism. In addition, cytokines damage the blood-brain-barrier and exert direct cytotoxic effects. This results in histologic detectable neuronal damage. Further effects of the cytokine expression are perivascular edema and hemorrhage. The loss of metabolic regulation of the brain perfusion and local cerebral ischemia additionally contribute to the etiology of septic encephalopathy. A specific therapy is not yet known.