Sepsis

From Wikipedia, the free encyclopedia

Sepsis (in Greek Σήψις, putrefaction) 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.

Symptoms

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.^[1]

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,^[2] 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:^[3]

• 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 P_aCO₂ 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."

Patients are defined as having "Severe Sepsis" if they have sepsis plus signs of end organ dysfunction. Patient are defined as having Septic Shock if they have sepsis plus hypotension after an appropriate fluid bolus.

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).

Treatment

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.

Early Goal Directed Therapy (EGDT), developed at Henry Ford Hospital by E. Rivers, MD, is a systematic approach to resuscitation that has been validated in the treatment of severe sepsis and septic shock. It is meant to be started in the Emergency Department. The theory is that one should use a step-wise approach, having the patient meet physiologic goals, to optimze cardiac preload, afterload, and contractility, thus optimizing oxygen delivery to the tissues.^[4]

In EGDT, fluids are administered until the central venous pressure (CVP), as measured by a central venous catheter reachs 8-12 cm of water (or 10-15 cm of water in mechanically ventilated patients). If the mean arterial pressure is less than 65 mmHg or greater than 90 mmHg, vasopressors or vasodilators are given as needed to reach the goal. Once these goals are met the central venous saturation (ScvO2), i.e. the oxgyen saturation of venous blood as it returns to the heart as measured at the superior vena cava, is optimized. If the ScvO2 is less than 70%, blood is given to reach a hemoglobin of 10 g/dl and then inotropes are added until the ScvO2 is optimized. Elective intubation may be performed to reduce oxygen demand if the ScVO2 remains low despite optimization of hemodynamics. Urine output is also monitored, with a goal of 0.5 ml/kg/h. In the original trial, mortality was cut from 46.5% in the control group to 30.5% in the intervention group. ^[5] The Surviving Sepsis Campaign guidelines recommends EGDT for the initial resuscitation of the septic patient with a level B strength of evidence (single randomized control trial). ^[6]

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.^[7] Low dose hydrocortisone treatment has shown promise for septic shock patients with relative adrenal insufficiency as defined by ACTH stimulation testing.^[8]

Standard treatment of infants with suspected sepsis consists of supportive care, maintaining fluid status with intravenous fluids, and the combination of a beta-lactam antibiotic (such as ampicillin) with an aminoglycoside such as gentamicin.

Related conditions/complications

• Infection is the invasion of normally sterile host tissues by a microbial pathogens.
• Bacteraemia is the presence of bacteria in the blood. Bacteraemia can occur in sepsis and other serious diseases such as infective endocarditis, but it may also be a harmless and transient condition.
• Septic joint is an infection of a joint; it is associated with bacteremia and trauma.
• Diffuse intravascular coagulation (DIC) can be the result of sepsis
• Acute tubular necrosis (ATN) leading to acute renal failure, can be the result of hypoperfusion of the kidneys in sepsis (i.e. not enough blood gets to the kidney and they stop working properly)
• Arrhythmia is an abnormal heart rhythm; it can be the result of sepsis.
• Ileus or ischemic colitis can be the result (hypoperfusion) or cause of sepsis
• Multiple organ dysfunction syndrome can be the result of sepsis
• Meningitis, infection of the tissue that covers the brain and spinal cord, can be a complication or cause of sepsis
• Osteomyelitis is an infection of the bone; it can be the cause or result of sepsis
• Endocarditis, infection of the inner surface of heart which is in contact with blood, can also be a complication or cause of sepsis
• Pyaemia- causes abscesses

References

1. ^ Martin GS, Mannino DM, Eaton S, Moss M. The epidemiology of sepsis in the United States from 1979 through 2000. N Engl J Med. 2003 Apr 17;348(16):1546-54. PMID 12700374 Full Text.
2. ^ Dellinger RP, Carlet JM, Masur H, Gerlach H, Calandra T, Cohen J, Gea-Banacloche J, Keh D, Marshall JC, Parker MM, Ramsay G, Zimmerman JL, Vincent JL, Levy MM; Surviving Sepsis Campaign Management Guidelines Committee. Surviving Sepsis Campaign guidelines for management of severe sepsis and septic shock. Crit Care Med. 2004 Mar;32(3):858-73. Erratum in: Crit Care Med. 2004 Jun;32(6):1448. Correction of dosage error in text. Crit Care Med. 2004 Oct;32(10):2169-70. PMID 15090974.
3. ^ Bone RC, Balk RA, Cerra FB, Dellinger RP, Fein AM, Knaus WA, Schein RM, Sibbald WJ. Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. The ACCP/SCCM Consensus Conference Committee. American College of Chest Physicians/Society of Critical Care Medicine. Chest. 1992 Jun;101(6):1644-55. PMID 1303622.
4. ^ Rivers E, Nguyen B, Havstad S, Ressler J, Muzzin A, Knoblich B, Peterson E, Tomlanovich M; Early Goal-Directed Therapy Collaborative Group. Early goal-directed therapy in the treatment of severe sepsis and septic shock. N Engl J Med. 2001 Nov 8;345(19):1368-77.
5. ^ Ibid.
6. ^ Dellinger RP, Carlet JM, Masur H, Gerlach H, Calandra T, Cohen J, Gea-Banacloche J, Keh D, Marshall JC, Parker MM, Ramsay G, Zimmerman JL, Vincent JL, Levy MM; Surviving Sepsis Campaign Management Guidelines Committee. Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock Crit Care Med 2004 March; 32(3):858-873
7. ^ Bernard GR, Vincent JL, Laterre PF, LaRosa SP, Dhainaut JF, Lopez-Rodriguez A, Steingrub JS, Garber GE, Helterbrand JD, Ely EW, Fisher CJ Jr; Recombinant human protein C Worldwide Evaluation in Severe Sepsis (PROWESS) study group. Efficacy and safety of recombinant human activated protein C for severe sepsis. N Engl J Med. 2001 Mar 8;344(10):699-709. PMID 11236773 Full Text.
8. ^ Annane D, Sebille V, Charpentier C, Bollaert PE, Francois B, Korach JM, Capellier G, Cohen Y, Azoulay E, Troche G, Chaumet-Riffaut P, Bellissant E. Effect of treatment with low doses of hydrocortisone and fludrocortisone on mortality in patients with septic shock. JAMA. 2002 Aug 21;288(7):862-71. PMID 12186604.

See also

• Meningococcemia
• Septic shock
• Systemic inflammatory response syndrome

External links

• Surviving Sepsis Campaign
• International Sepsis Forum
• Advances in Sepsis journal
• sepsis.com: [1]
• Medscape Sepsis Resource Center
• Diagnostic Criteria for Sepsis, MedicalCriteria.com