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Systemic Inflammatory Response Syndrome

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Systemic Inflammatory Response Syndrome, SIRS

  • See Also
  1. Sepsis in Adults
  2. Sepsis in Children
  3. qSOFA Score
  4. Sequential Organ Failure Assessment Score (SOFA Score)
  • Indications
  1. Sepsis Evaluation (replaced by SOFA Score and qSOFA Score as of 2016)
  • Background
  1. SIRS suggests an inflammatory response
  2. SIRS is a screening tool for Sepsis
    1. High Test Sensitivity for Sepsis
    2. Poor Test Specificity for Sepsis (any inflammation can cause SIRS)
  3. Sepsis is present when infection accompanies at least 2 positive SIRS criteria
    1. Significance of this definition of Sepsis is that it is correlated with a higher mortality risk than infection without SIRS
  • Efficacy
  1. Sepsis Test Sensitivity: 50-60%
    1. Fails to identify one in eight patients admitted to ICU with severe Sepsis
    2. Tusgul (2017) Scand J Trauma Resusc Emerg Mefd 25(1):108 [PubMed]
    3. Kaukonen (2015) N Engl J Med 372(17): 1629-38 [PubMed]
  • Criteria
  • Adults (Positive if 2 of the 4 signs are present)
  1. Body Temperature < 36 C (96.8 F) or > 38 C (100.4 F)
  2. Heart Rate >90 bpm
  3. Tachypnea (>20 breaths per minute) or PaCO2 <32 mmHg
  4. White Blood Cell Count <4000 cells/mm3 or >12,000 cells/mm3 or >10% immature Neutrophils (Band Neutrophils)
  • Criteria
  • Children (Positive if 2 of the 4 signs are present)
  1. Major (at least one of these must be present)
    1. Core Temperature >38.5 C (101.3 F) or <36 C (96.8 F)
    2. Leukocyte count elevated or depressed for age or >10% immature Neutrophils (Band Neutrophils)
      1. Abnormal Leukocyte count not due to Chemotherapy
  2. Minor
    1. Tachypnea
      1. Mean Respiratory Rate >2 SD above normal for age or
      2. Mechanical Ventilation for acute reason not related to underlying neuromuscular disorder or general Anesthesia
    2. Abnormal Heart Rate
      1. Tachycardia
        1. Mean Heart Rate 2 SD above normal for age or unexplained persistent elevation for at least 0.5 hours
        2. Not due to external or painful stimuli, longterm medication use
      2. Bradycardia in children <1 year of age
        1. Mean Heart Rate <10th percentile for age or unexplained persistent depression for at least 0.5 hours
        2. Not due to external Vagal Stimulation, Beta Blockers or Congenital Heart Disease
  1. Age <1 week
    1. Heart Rate >180 or <100 per minute
    2. Respiratory Rate >50 per minute
    3. White Blood Cell Count >34k
  2. Age 1 to 4 weeks
    1. Heart Rate >180 or <100 per minute
    2. Respiratory Rate >40 per minute
    3. White Blood Cell Count >19.5k or <5.5k
  3. Age 1 to 24 months
    1. Heart Rate >180 or <90 per minute
    2. Respiratory Rate >34 per minute
    3. White Blood Cell Count >17.5k or <5.5k
  4. Age 2 to 6 years
    1. Heart Rate >140 per minute
    2. Respiratory Rate >22 per minute
    3. White Blood Cell Count >15.5k or <6k
  5. Age 6 to 13 years
    1. Heart Rate >130 per minute
    2. Respiratory Rate >18 per minute
    3. White Blood Cell Count >13.5k or 4.5k
  6. Age 13 to 18 years
    1. Heart Rate >110 per minute
    2. Respiratory Rate >14 per minute
    3. White Blood Cell Count >11k or <4.5k
  • Differential Diagnosis
  1. Infection (Sepsis)
    1. Bacterial Infection (most common)
    2. Also fungal, parasitic or Viral Infection
  2. Trauma
  3. Burn Injury
  4. Post-surgery
  5. Pancreatitis
  6. Pulmonary Embolism
  7. Anaphylaxis
  8. Drug Overdose
  9. Vasculitis
  10. Autoimmune syndrome
  • References
  1. Khoujah (2013) Crit Dec Emerg Med 27(4):12-21
  2. Annane (2005) Lancet 365(9453): 63-78 [PubMed]
  3. Bone (1992) Chest 101:1644-55 [PubMed]
  4. Goldstein (2005) Pediatr Crit Care Med 6:2-8 [PubMed]