AskDefine | Define sepsis

Dictionary Definition

sepsis n : the presence of pus-forming bacteria or their toxins in the blood or tissues

User Contributed Dictionary

English

Noun

Derived terms

Extensive Definition

Sepsis is a serious medical condition characterized by a whole-body inflammatory state caused by infection.
Sepsis is broadly defined as the presence of various pus-forming and other pathogenic organisms, or their toxins, in the blood or tissues. While the term sepsis is frequently used to refer to septicemia (blood poisoning), septicemia is but one type of sepsis. Bacteremia specifically refers to the presence of bacteria in the bloodstream (viremia and fungemia are analogous terms for viruses and fungi).

Signs and symptoms

In addition to symptoms related to the provoking infection, sepsis is characterized by evidence of acute inflammation present throughout the entire body, and is therefore frequently associated with fever and elevated white blood cell count (leukocytosis). The modern concept of sepsis is that the host's immune response to the infection causes most of the symptoms of sepsis, resulting in hemodynamic consequences and damage to organs. This host response has been termed systemic inflammatory response syndrome (SIRS) and is characterized by hemodynamic compromise and resultant metabolic derangement.
This immunological response causes widespread activation of acute phase proteins, affecting the complement system and the coagulation pathways, which then cause damage to the vasculature as well as to the organs. Various neuroendocrine counter-regulatory systems are then activated as well, often compounding the problem. Even with immediate and aggressive treatment, this may progress to multiple organ dysfunction syndrome and eventually death.

Epidemiology

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 data from the Centers for Disease Control and Prevention. 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.

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:
Fever and leukocytosis are features of the acute phase reaction, while tachycardia is often the initial sign of hemodynamic compromise. Tachypnea may be related to the increased metabolic stress due to infection and inflammation, but may also be an ominous sign of inadequate perfusion resulting in the onset of anaerobic cellular metabolism.
In children, the SIRS criteria are modified in the following fashion:
Note that SIRS criteria are very non-specific, and must be interpreted carefully within the clinical context. These criteria exist primarily for the purpose of more objectively classifying critically-ill patients so that future clinical studies may be more rigorous and more easily reproducible.
Consensus definitions however continue to evolve with the latest expanding the list of signs and symptoms of sepsis to reflect clinical bedside experience.
More specific definitions of end-organ dysfunction exist for SIRS in pediatrics.:
  • generally well appearing
  • previously healthy
    • full term (at ≥37 weeks gestation)
    • no antibiotics perinatally
    • no unexplained hyperbilirubinemia that required treatment
    • no antibiotics since discharge
    • no hospitalizations
    • no chronic illness
    • discharged at the same time or before the mother
  • no evidence of skin, soft tissue, bone, joint, or ear infection
  • WBC count 5,000-15,000/mm3
  • absolute band count ≤ 1,500/mm3
  • urine WBC count ≤ 10 per high power field (hpf)
  • stool WBC count ≤ 5 per high power field (hpf) only in infants with diarrhea
Those meeting these criteria likely do not require a lumbar puncture, and are felt to be safe for discharge home without antibiotic treatment, or with a single dose of intramuscular antibiotics, but will still require close outpatient follow-up.

Treatment

Sepsis in Adults and Children

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—preferrably by enteral feeding, but if necessary by parenteral nutrition—is important during prolonged illness.
A problem in the adequate management of septic patients has been the delay in administering therapy after sepsis has been recognized. Published studies have demonstrated that for every hour delay in the administration of appropriate antibiotic therapy there is an associated 7% rise in mortality. 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.
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 optimize cardiac preload, afterload, and contractility, thus optimizing oxygen delivery to the tissues.
In EGDT, fluids are administered until the central venous pressure (CVP), as measured by a central venous catheter, reaches 8-12 cm of water (or 10-15 cm of water in mechanically ventilated patients). This may require around 6 liters of isotonic crystalloid solution, rapidly administered. 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 mixed venous oxygen saturation (SvO2), i.e. the oxygen saturation of venous blood as it returns to the heart as measured at the vena cava, is optimized. If the SvO2 is less than 70%, blood is given to reach a hemoglobin of 10 g/dl and then inotropes are added until the SvO2 is optimized. Elective intubation may be performed to reduce oxygen demand if the SvO2 remains low despite optimization of hemodynamics. Urine output is also monitored, with a minimum 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. Low dose hydrocortisone treatment has shown promise for septic shock patients with relative adrenal insufficiency as defined by ACTH stimulation testing.

Rule Out Sepsis and Suspected Sepsis in Neonates

Note that in neonates, sepsis is difficult to diagnose clinically. They may be relatively asymptomatic until hemodynamic and respiratory collapse is imminent, so if there is even a remote suspicion of sepsis, they are frequently treated with antibiotics empirically until cultures are sufficiently proven to be negative. In addition to fluid resuscitation and supportive care, a common antibiotic regimen in infants with suspected sepsis is a beta-lactam antibiotic (usually ampicillin) in combination with an aminoglycoside (usually gentamicin) or a third-generation cephalosporin (usually cefotaximeceftriaxone is generally avoided in neonates due to the theoretical risk of causing biliary stasis.) The organisms which are targeted are species that predominate in the female genitourinary tract and to which neonates are especially vulnerable to, specifically Group B Streptococcus, Escherichia coli, and Listeria monocytogenes (This is the main rationale for using ampicillin versus other beta-lactams.) Of course, neonates are also vulnerable to other common pathogens that can cause meningitis and bacteremia such as Streptococcus pneumoniae and Neisseria meningitidis. Although uncommon, if anaerobic species are suspected (such as in cases where necrotizing enterocolitis or intestinal perforation is a concern, clindamycin is often added.

Prognosis

Prognosis can be estimated with the MEDS score.

Related conditions/complications

External links

sepsis in Czech: Sepse
sepsis in Danish: Sepsis
sepsis in German: Sepsis
sepsis in Modern Greek (1453-): Σήψη
sepsis in Spanish: Sepsis
sepsis in Esperanto: Sepso
sepsis in Basque: Septizemia
sepsis in Persian: سپتیسمی
sepsis in French: Septicémie
sepsis in Croatian: Sepsa
sepsis in Indonesian: Sepsis
sepsis in Italian: Sepsi
sepsis in Hebrew: אלח דם
sepsis in Latvian: Sepse
sepsis in Dutch: Sepsis
sepsis in Japanese: 敗血症
sepsis in Norwegian: Sepsis
sepsis in Polish: Sepsa
sepsis in Portuguese: Sepse
sepsis in Russian: Сепсис
sepsis in Simple English: Sepsis
sepsis in Slovak: Sepsa
sepsis in Serbian: Сепса
sepsis in Finnish: Verenmyrkytys
sepsis in Swedish: Sepsis
sepsis in Vietnamese: Nhiễm trùng huyết
sepsis in Turkish: Septisemi
sepsis in Chinese: 敗血症
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