Sepsis is a serious medical condition, resulting from the immune response to a severe infection. Septicemia is sepsis of the bloodstream caused by bacteremia, which is the presence of bacteria in the bloodstream. The term septicemia is also used to refer to sepsis in general.
The immunological response that causes sepsis is a systemic inflammatory response causing widespread activation of inflammation and coagulation pathways. This may progress to dysfunction of the circulatory system and, even under optimal treatment, may result in the multiple organ dysfunction syndrome and eventually death.
Sepsis is common and also more dangerous in elderly, immunocompromised, and critically ill patients. It occurs in 1%-2% of all hospitalizations and accounts for as much as 25% of intensive care unit (ICU) bed utilization. It is a major cause of death in intensive care units worldwide, with mortality rates that range from 20% for sepsis to 40% for severe sepsis to >60% for septic shock. In the United States, sepsis is the leading cause of death in non-coronary ICU patients, and the tenth most common cause of death overall according to 2000 data from the Centers for Disease Control and Prevention.
A problem in the adequate management of septic patients has been the delay in administering the right treatment after sepsis has been recognized. A large international collaboration was established to educate people about sepsis and to improve patient outcomes with sepsis, entitled the "Surviving Sepsis Campaign." The Campaign has published an evidence-based review of management strategies for severe sepsis, with the aim to publish a complete set of guidelines in subsequent years.
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).
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."
The therapy of sepsis rests on antibiotics, surgical drainage of infected fluid collections, fluid replacement and appropriate support for organ dysfunction. This may include hemodialysis in kidney failure, mechanical ventilation in pulmonary dysfunction, transfusion of blood products, and drug and fluid therapy for circulatory failure. Ensuring adequate nutrition, if necessary by parenteral nutrition, is important during prolonged illness.
Most therapies aimed at the inflammatory process itself have failed to improve outcome. However, drotrecogin alfa (activated protein C, one of the coagulation factors) has been shown to decrease mortality from about 31% to about 25% in severe sepsis. Low dose hydrocortisone treatment has shown promise for septic shock patients with relative adrenal insufficiency as defined by ACTH stimulation testing.