How are acute and chronic inflammation differentiated histologically?

• A. Acute inflammation is neutrophil-rich with edema; chronic inflammation features lymphocytes/macrophages, plasma cells, fibrosis, and angiogenesis.
• B. Acute is granulomatous; chronic purulent
• C. Acute inflammation has macrophages; chronic neutrophils
• D. Acute inflammation is fibrotic; chronic edema

Answer: (A)

The main idea is that histology differentiates acute from chronic inflammation by the types of inflammatory cells and the tissue changes they produce. Acute inflammation is characterized by a rapid influx of neutrophils and increased vascular permeability, which leads to edema and an exudate rich in neutrophils. This reflects the immediate defense against injury or infection and often resolves quickly.

Chronic inflammation, by contrast, shows a shift to mononuclear cell infiltrates—predominantly lymphocytes and macrophages—with possible plasma cell involvement. Over time, tissue destruction by these cells is accompanied by repair processes such as fibrosis (scar formation) and angiogenesis to restore blood supply and structure. This pattern arises when the stimulus persists or tissue injury continues, requiring ongoing immune activity and remodeling.

Thus the description that acute inflammation is neutrophil-rich with edema, while chronic inflammation features lymphocytes and macrophages, plasma cells, fibrosis, and angiogenesis, best captures the histologic distinction.

Why the other statements don’t fit: granulomatous inflammation is a chronic pattern dominated by macrophages forming granulomas, not an acute feature; purulent (pus) describes a neutrophil-rich exudate typical of acute processes, not chronic; macrophages are more characteristic of chronic inflammation, whereas acute inflammation is driven by neutrophils; and fibrosis is a hallmark of chronic repair, not acute, while edema is more common in acute phases.