VIII.CHRONIC INFLAMMATION Definition: Chronic inflammation can be defined as a prolonged inflammatory process (weeks or months) where an active inflammation, tissue destruction and attempts at repair are proceeding simultaneously. Causes of chronic inflammation: 1. Persistent infections Certain microorganisms associated with intracellular infection such as tuberculosis, leprosy, certain fungi etc characteristically cause chronic inflammation. These organisms are of low toxicity and evoke delayed hypersensitivity reactions. 2. 3. Prolonged exposure to nondegradable but partially toxic substances either endogenous lipid components which result in atherosclerosis or exogenous substances such as silica, asbestos. Progression from acute inflammation: Acute inflammation almost always progresses to chronic inflammation following: a. Persistent suppuration as a result of uncollapsed abscess cavities, foreign body materials (dirt, cloth, wool, etc), sequesterum in osteomylitis, or a sinus/fistula from chronic abscesses. 4. Autoimmuniy. Autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosis are chronic inflammations from the outset. Morphology: Cells of chronic inflammation: Monocytes and Macrophages are the prima Dona (primary cells) in chronic inflammation. Macrophages arise from the common precursor cells in the bone marrow, which give rise to blood monocytes. These cells are then diffusely scattered in various parts of the body, in the liver (Kupffer cells), spleen, lymph nodes (sinus histiocytes), lungs (alviolar macrophages), bone marrow, brain (microglia
Posted on: Tue, 13 Aug 2013 16:56:00 +0000
Trending Topics
Recently Viewed Topics
© 2015