Pathophysiology
Clinical meaning
Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. The immune system's overactivation triggers a cascade of inflammatory mediators (TNF-α, IL-1, IL-6), endothelial damage, microvascular thrombosis, and tissue hypoperfusion leading to progressive organ failure. Screening Tools: 1. SIRS Criteria (Systemic Inflammatory Response Syndrome): ≥2 of the following: • Temperature >38°C (100.4°F) OR <36°C (96.8°F) • Heart rate >90 bpm • Respiratory rate >20/min OR PaCO2 <32 mmHg • WBC >12,000 OR <4,000 OR >10% bands (immature neutrophils) SIRS is SENSITIVE but not SPECIFIC: many conditions trigger SIRS without infection. 2. qSOFA (Quick Sequential Organ Failure Assessment): ≥2 of: • Respiratory rate ≥22/min • Altered mentation (any change from baseline) • Systolic blood pressure ≤100 mmHg qSOFA is a bedside screening tool: it does NOT require lab work. Score ≥2 should trigger a full sepsis workup and SOFA calculation. 3. SOFA Score (Sequential Organ Failure Assessment): Assesses 6 organ systems (respiratory, coagulation, liver, cardiovascular, CNS, renal) with scores 0-4 each. An acute increase of ≥2 points from baseline in the setting of known/suspected infection = Sepsis....