NEUROLOGICAL COMPLICATIONS IN CRITICALLY ILL PATIENTS - SEPTIC ENCEPHALOPATHY, CRITICAL ILLNESS POLYNEUROPATHY

Septic encephalopathy and critical illness polyneuropathy are two synd romes, appearing at different stages in critically ill patients. Their aetiology is unclear but many arguments seem to associate them with r espiratory insufficiency in a context of systemic inflammatory respons e syndrome (S.I.R.S.) and multiple organ dysfunction syndrome (M.O.D.S .). Septic encephalopathy appears early in the course of sepsis, diagn osis is based on clinical picture and electroencephalogram. The exact pathogenesis is unclear. Prognosis is related to the underlying pathol ogy, and treatment is supportive. Critical illness polyneuropathy is a predominantly motor axonal dysfunction, occurring in a setting of res piratory insufficiency, S.I.R.S., and M.O.D.S.. A weaning problem ofte n indicates the presence of critical illness polyneuropathy. Diagnosis is made on history, clinical picture and electromyographic studies. I ndeed, motor and sensory conduction studies show a reduction of the am plitude of action potentials. In a later stage fibrillations and posit ive sharp waves emerge, with a further reduction of action potentials. Follow-up examinations reveal signs of axonal regeneration. The exact aetiology is unknown, but may be related to sepsis and M.O.D.S. Sepsi s and M.O.D.S. are associated with the release of ''mediator'' substan ces, and somewhere in this cascade, there might be a toxin, influencin g the nerve. A differential diagnosis with myopathy and neuromuscular transmission defects has to be made. Specific treatment is absent, and prognosis is related to the underlying pathology.