Chronic Inflammation Flashcards
What are the 4 possible outcomes of acute inflammation?
- Complete Resolution
- Healing by scarring
- Abscess formation
- Progression to chronic inflammation
What does Resolution involve?
Resolution involves neutralization of the chemical mediators, with subsequent return of normal vascular permeability, cessation of leucocytic infiltration and finally removal of edema fluid, leucocytes, foreign agents and necrotic debris.
Define Chronic Inflammation…
Chronic inflammation: is a type of inflammation resulting from injurious persistent stimuli (often weeks or months), which leads to a predominantly proliferative, rather than an exudative, reaction.
What is the Hallmark of Chronic Inflammation?
Fibrosis
What are the Histologic Hallmarks of Chronic Inflammation?
- infiltration by mononuclear cells, principally macrophages, lymphocytes, and plasma cells
- proliferation of fibroblasts and in many instances, small blood vessels,
- increased connective tissue (fibrosis)
- tissue destruction
Define Granulomatous Inflammation…
Granulomatous inflammation is a specific type of chronic inflammation characterized by accumulation of modified macrophages: epithelioid cells, and initiated by a variety of infectious and noninfectious agents.
Define Granuloma…
Granuloma: small, 0.5 to 2‐mm, organized collections of modified macrophages called epithelioid macrophages, usually surrounded by a rim of lymphocytes. Another feature of the granuloma is the presence of Langhan’s giant or foreign body‐type cells and presence of fibrous connective tissue.
What type of stimuli results in granulomatous inflammation?
Stimuli resistant to phagocyte killing and degradation.
What are the cells involved in Granulomatous Inflammation?
Epithelioid cells
Multinucleated giant cells
Lymphocytes
Describe epithelioid cells…
These are large, pale‐staining macrophages that have an ovoid nucleus and a shape resembling epithelial cells.
Describe Multinucleate Giant Cells..
Multinucleate giant cells may achieve a diameter of 40 to 50 μm and contain over 50 nuclei.
• Nuclei are sometimes arranged around the periphery (creating a horseshoe pattern: Langhan’s giant cells).
• The multinucleated cell function is similar to that of the epithelioid cell.
What are the roles of T Lymphocytes in Granulomatous Inflammation?
– to produce lymphokines and interferon
– to attract and activate macrophages
– to induce formation of multinucleated giant cells
If..significant numbers of neutrophils are present in the centre of a granulomatous reaction, what type of inflammation is present?
Pyogranulomatous Inflammation
What are the types of granulomas?
Simple and Complex!
What is a Simple Granuloma?
organized accumulation of macrophages and epithelioid cells, often rimmed by lymphocytes.
