Q) A 28-year-old male is brought to the ED after a road traffic accident with polytrauma. He undergoes emergency laparotomy for splenic injury. On postoperative day 1, he develops fever (38.7°C), tachycardia (120/min), leukocytosis (18,000/µL), and hypotension requiring fluids. Blood and urine cultures are negative. No evidence of pneumonia is seen on chest X-ray.
Which of the following best explains his condition?
Which of the following best explains his condition?
✅ Answer: B. Sterile systemic inflammatory response due to DAMP release
🔍 Explanation:
Trauma and major surgery cause tissue necrosis, ischemia, and cellular injury. Intracellular molecules such as HMGB1, mitochondrial DNA, ATP, uric acid, and heat shock proteins are released and act as DAMPs (damage-associated molecular patterns).
These activate innate immune receptors like Toll-like receptors and inflammasomes (e.g., NLRP3), triggering a robust inflammatory response even in the absence of infection. This explains sterile SIRS, which can mimic sepsis but with negative cultures.
🧠 Key Point: DAMP-driven sterile inflammation is common after trauma, burns, pancreatitis, and ischemia-reperfusion injuries. It must be differentiated from infection-driven SIRS (PAMP-mediated sepsis).
🔍 Explanation:
Trauma and major surgery cause tissue necrosis, ischemia, and cellular injury. Intracellular molecules such as HMGB1, mitochondrial DNA, ATP, uric acid, and heat shock proteins are released and act as DAMPs (damage-associated molecular patterns).
These activate innate immune receptors like Toll-like receptors and inflammasomes (e.g., NLRP3), triggering a robust inflammatory response even in the absence of infection. This explains sterile SIRS, which can mimic sepsis but with negative cultures.
🧠 Key Point: DAMP-driven sterile inflammation is common after trauma, burns, pancreatitis, and ischemia-reperfusion injuries. It must be differentiated from infection-driven SIRS (PAMP-mediated sepsis).