Acute inflammation
What it means
Rapid, neutrophil-driven response. Five cardinal signs: rubor, calor, tumor, dolor, functio laesa. Vascular changes (vasodilation, ↑permeability → exudate) + cellular events (neutrophil margination, diapedesis, chemotaxis to C5a, IL-8, LTB4, fMLP). Mediators: histamine, bradykinin, prostaglandins, complement.
Worked example
A red, hot, swollen, painful joint with a neutrophil-rich exudate = acute inflammation.
In the exam
Within hours of injury an area becomes red, hot, swollen and painful, with neutrophils migrating from dilated, leaky vessels.
What settles it
Acute inflammation = neutrophils, rapid, exudative; chronic inflammation = lymphocytes/plasma cells/macrophages with simultaneous tissue destruction and repair (fibrosis).
Classically confused with
Chronic inflammation
Source: StatPearls — Inflammation