The Systemic Inflammatory Response Syndrome (SIRS) is the biologic host response to real or perceived infection which may occur in response to several severe clinical conditions.
Definitions:
(1) infection: Microbial phenomenon characterized by an inflammatory response to the presence of microorganisms or the invasion of normally sterile host tissue by those organisms.
(2) bacteremia: The presence of viable bacteria in the blood.
(3) septicemia: It is recommended that the term not be used to clinically describe patients.
The stages in response to infection may be viewed as a continuum:
(1) SIRS
(2) sepsis
(3) severe sepsis
(4) septic shock
(5) end-organ dysfunction, often manifested as the multiple organ dysfunction syndrome
(6) death
Criteria for diagnosis of SIRS - Two or more of the following conditions:
(1) temperature > 38° C or < 36° C
(2) heart rate > 90 beats per minute
(3) respiratory rate > 20 breaths per minute OR PaCO2 < 32 mm Hg
(4) WBC > 12,000 per µL OR < 4,000 per µL OR > 10% immature forms
where
• The factor for converting PaCO2 to kPa is 0.133
|
Syndrome |
Cultures |
Features |
|---|---|---|
|
sepsis |
• positive |
• SIRS
|
|
severe sepsis |
• positive |
• SIRS • organ dysfunction, hypoperfusion abnormalities, or hypotension |
|
septic shock |
• positive |
• SIRS • sepsis-induced hypotension despite fluid resuscitation • hypoperfusion abnormalities |
|
culture negative sepsis |
• negative • empirical antibiotic therapy for a clinically suspected infection |
• SIRS |
|
culture negative severe sepsis |
• negative • empirical antibiotic therapy for a clinically suspected infection |
• SIRS • organ dysfunction, hypoperfusion abnormalities, or hypotension |
|
culture negative septic shock |
• negative • empirical antibiotic therapy for a clinically suspected infection |
• SIRS • sepsis-induced hypotension despite fluid resuscitation • hypoperfusion abnormalities |
where:
• Hypoperfusion abnormalities may include lactic acidosis, oliguria, or an acute alteration in mental status.
• Hypotension indicates a systolic blood pressure of < 90 mm Hg or a reduction of > 40 mm Hg from baseline in the absence of other causes for hypotension.
• Patients with septic shock receiving inotropic or vasopressor agents may not be hypotensive at the time that perfusion abnormalities are measured.
Mortality rates shows a stepwise increase paralleling the increased severity of the reaction.
|
Syndrome |
Mortality Rate |
|---|---|
|
SIRS |
7% |
|
sepsis |
16% |
|
severe sepsis |
20% |
|
septic shock |
46% |
Purpose: To evaluate a patient for the Systemic Inflammatory Response Syndrome.
Specialty: Critical Care, Emergency Medicine, Infectious Diseases
Objective: clinical diagnosis, including family history for genetics, severity, prognosis, stage
ICD-10: R65,
