[Diagnosis of sepsis, severe sepsis and septic shock]

Consensual and precise definitions. Sepsis is composed of a suspected or documented infection associated with at least 2 SIRS criteria (systemic inflammatory response syndrome). Severe sepsis is sepsis with arterial hypotension and failure of one or several organs following the reduction in tIssue perfusion. Septic shock is a severe sepsis, the hypotension of which is refractory to volemic expansion. From an epidemiological point of view. Over the past two decades, its incidence is on the increase. Mortality varies from 25 to 80% of cases and sepsis remains the first cause of death in intensive care. The elements of diagnosis. The initial clinical signs are those of an infection and the port of entry and microbiological proof must be systematically researched before the appearance of a drop in blood pressure with hemodynamic impact on the various organs and hence their possible failure. The biological abnormalities observed depend on the deficient organ(s); hyperlactatemia is a good marker of visceral hypoperfusion. The sepsis risk factors. Any situation enhancing immunodepression is a risk factor for sepsis. Factors of virulence of the micro-organisms also intervene and, in cases of fungal infection, inherent risk factors. Genetic susceptibility probably intervenes, genetic variability playing either a protective or a deleterious role (the interest of Toll-like receptors).