Sepsis overview

Overview
Sepsis is a serious medical condition characterized by a whole-body inflammatory state caused by infection.

Traditionally the term sepsis has been used interchangeably with septicaemia and septicemia ("blood poisoning"). However, these terms are no longer considered synonymous; septicemia is considered a subset of sepsis.

Definition of sepsis
Sepsis is considered present if infection is highly suspected or proven and two or more of the following systemic inflammatory response syndrome (SIRS) criteria are met:


 * Heart rate > 90 beats per minute
 * Body temperature < 36 (96.8 °F) or > 38 °C (100.4 °F)
 * Hyperventilation (high respiratory rate) > 20 breaths per minute or, on blood gas, a PaCO2 less than 32 mm Hg
 * White blood cell count < 4000 cells/mm³ or > 12000 cells/mm³ (< 4 x 109 or > 12 x 109 cells/L), or greater than 10% band forms (immature white blood cells).

Consensus definitions however continue to evolve with the latest expanding the list of signs and symptoms of sepsis to reflect clinical bedside experience.

The more critical subsets of sepsis are severe sepsis (sepsis with acute organ dysfunction) and septic shock (sepsis with refractory arterial hypotension). Alternatively, when two or more of the systemic inflammatory response syndrome criteria are met without evidence of infection, patients may be diagnosed simply with "SIRS." Patients with SIRS and acute organ dysfunction may be termed "severe SIRS."

Patients are defined as having "severe sepsis" if they have sepsis plus signs of systemic hypoperfusion; either end organ dysfunction or a serum lactate greater than 4 mmol/dL. Patient are defined as having septic shock if they have sepsis plus hypotension after an appropriate fluid bolus (typically 20 ml/kg of crystaloid).

The criteria for diagnosing an adult with sepsis do not apply to infants under one month of age. In infants, only the presence of infection plus a "constellation" of signs and symptoms consistent with the systemic response to infection are required for diagnosis (Oski's Pediatrics, 2006).

Related Chapters

 * Septic shock