The Spectrum of Septic Encephalopathy: Definitions, Etiologies, and Mortalities

Abstract

OBJECTIVE: To determine whether the severity of septic encephalopathy is correlated with gram-negative bacteremia and mortality and whether there exists a single or combination of metabolic derangements(s) that cause septic encephalopathy. DESIGN AND SETTING: Prospective case series in an academic medical center. PATIENTS: Fifty patients selected according to clinical and laboratory criteria for severe sepsis. The criteria included temperature, heart rate, respiratory rate, and hypotension and/or signs of systemic hypoperfusion. MAIN OUTCOME MEASURES: A single or combination of metabolic and laboratory derangements and organ failures, three different methods to grade the severity of septic encephalopathy, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, gram-negative bacteremia and infection, and mortality. RESULTS: Encephalopathy was associated with an increase in mortality when graded by the Glasgow Coma Score; a score of 15 had 16% mortality, 13 to 14 had 20%, 9 to 12 had 50%, and 3 to 8 had 63% mortality (P < .05). Bacteremia was associated with encephalopathy; 13% of septic patients without encephalopathy vs 59% of patients with encephalopathy had bacteremia (P < .001) when graded by altered mental status. Septic encephalopathic patients had elevated serum urea nitrogen and bilirubin levels, increased APACHE II scores, and a higher incidence of renal failure. CONCLUSIONS: The severity of septic encephalopathy correlated with mortality, bacteremia, and renal and hepatic dysfunction. The Glasgow Coma Score is a useful tool for characterizing septic encephalopathy. Considerable variations can be found according to different criteria used to classify septic encephalopathy.