L6: Chronic Inflammation

What defines chronic inflammation?

A prolonged process where destruction and inflammation proceed simultaneously.

What are the two major chronic inflammatory processes?

1. Following acute inflammation 2. Distinct process from the outset.

List some causes of chronic inflammation.

Persistence of inciting stimulus, interference with normal healing, repeated bouts of acute inflammation, viral infections, persistent infections by microorganisms, insoluble particles, and autoimmune conditions.

What are the histologic hallmarks of chronic inflammation?

1. Infiltration by mononuclear cells, principally macrophages, lymphocytes and plasma cells. 2. Granulation tissue formation. 3. Fibrosis and tissue destruction. 4. Regeneration.

What is the characteristic morphological feature of granulomatous inflammation?

Granuloma: collections of modified macrophages (epithelioid cells) with abundant pale pink cytoplasm.

What are epithelioid cells?

Modified macrophages with abundant pink cytoplasm, resembling epithelial cells.

How does acute inflammation differ from chronic inflammation in terms of duration?

Acute inflammation lasts for days, while chronic inflammation can last for weeks to months.

What type of immune cells are primarily involved in chronic inflammation?

Macrophages, lymphocytes, polymorphonuclear leukocytes, and plasma cells.

What are some examples of granulomatous inflammation causes?

Bacterial infections like Mycobacterium tuberculosis, parasitic conditions like schistosomiasis, fungal infections like cryptococcus, and foreign bodies like silicosis.

What defines granulomatous inflammation?

Aggregations of epithelioid macrophages (granulomas) formed in response to indigestible agents or cell-mediated immunity.

What is pyogenic membrane?

Granulation tissue lining a pus-filled cavity in chronic suppurative inflammation.

What is the nature of acute inflammation compared to chronic inflammation?

Acute inflammation is usually exudative, while chronic inflammation is proliferative.

What consequences arise from chronic inflammation?

Destruction of tissues and organs, functional impairment, and scarring.

What are the effects of the biological products released by macrophages in chronic inflammation?

Cause tissue damage, recruit other cells, stimulate fibroblast/vascular proliferation, and promote collagen deposition.

How do lymphocytes contribute to chronic inflammation?

They produce lymphokines that activate macrophages and influence B-cell/T-cell functions.

What role do plasma cells play in chronic inflammation?

Produce antibodies against persistent antigens or altered tissue components.

What is granulation tissue composed of?

Fibroblasts, small blood vessels, and inflammatory cells.