Systemic Inflammatory Response Syndrome (SIRS)

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Key Points

Systemic inflammatory response syndrome (SIRS) is a state of systemic, dysregulated inflammation, triggered by either an infectious (septic) or non-infectious (sterile) cause
The inciting cause triggers mass release of inflammatory mediators, leading to vasodilation, capillary leak and coagulation activation
Early stage signs can include bounding pulses and hyperaemic mucous membranes but this can quickly progress to distributive shock
- Shock results in poor perfusion, anaerobic tissue metabolism and lactate accumulation
SIRS is suspected when ≥2 of the SIRS criteria are met, but should also be interpreted alongside the clinical presentation
- ↑ or ↓ temperature, tachycardia, tachypnoea and ↑ or ↓ WBC counts
Treatment includes immediate stabilisation, addressing the underlying cause and ensuring organ-specific support
Prognosis is variable depending on how early the condition is recognised and treatment

Differential Diagnoses

Educational content only. This factsheet is for general veterinary education and is not a substitute for professional veterinary advice, diagnosis, or treatment. Not for use in an emergency — contact a veterinarian or emergency service. Full disclaimer →