How is an abscess formed?
Answer:
causal agent -> chemotaxis -> neutrophil aggregation -> failure to rapidly eliminate inciting stimulus -> degranulation -> tissue damage, liquefaction -> fibroblasts proliferate and encircle pus
challenge overcome: pyogenic membrane contracts -> abscess cavity shrinks -> fills with connective tissue -> necrotic material absorbed by macrophages
challenge not overcome: abscess expands, increased internal pressure -> formation of sinus tract OR rupture OR chronic inflammatory process