Within hours of bacterial entry into a joint, what is the principal mechanism by which articular cartilage matrix is destroyed in untreated septic arthritis?
- A Proteolytic and elastolytic enzymes released from neutrophil lysosomes together with synovial cytokines ✓
- B Direct invasion of chondrocytes by bacteria
- C Autoimmune cross reactivity between bacterial antigens and type II collagen
- D Crystal deposition of calcium pyrophosphate in the damaged matrix
Correct answer: A. Proteolytic and elastolytic enzymes released from neutrophil lysosomes together with synovial cytokines
Explanation
Neutrophils recruited into the joint release lysosomal proteases and reactive oxygen species, and the inflamed synovium adds cytokine driven matrix metalloproteinase activity, so cartilage degradation begins within days even though bacteria themselves rarely invade chondrocytes. Chondrocyte death can begin within hours of raised intra-articular pressure and pus accumulation. This enzymatic destruction is why drainage cannot be delayed beyond a few days.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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