Course Teacher: Imon Rahman Inflammation Course Teacher: Imon Rahman

Inflammation Inflammation is a complex reaction to injurious agents such as microbes and damaged, usually necrotic cells that consists of vascular response, migration and activation of leukocytes and systemic reaction. Or Inflammation is the complex reaction of the living vascularized connective tissue towards an injury.

Types Acute inflammation: Acute inflammation is the inflammation of short duration (few mins to few days) by exudation of fluid and plasma protein and the emigration of leukocytes, predominantly neutrophils.

Cardinal Signs Rubor (Redness) Tumor (Swelling) Calor (heat) Dolor (Pain) Functio Laesa (loss of function)

Chronic inflammation It is defined as an inflammation of prolonged duration (weeks or months) in which active inflammation, tissue destruction and attempts at repair are proceeding simultaneously. Eg: Tuberculosis, Rheumatoid arthritis, atherosclerosis and chronic lung disease.

Histological features Infiltration with mononuclear cells, which include macrophages, lymphocytes and plasma cells. Tissue destruction, induced by persistent offending agent or by inflammatory cells. Attempts at healing by connective tissue replacement of damaged tissue, accomplished by proliferation of small blood vessels (angiogenesis) and in particular, fibrosis.

Causes of acute inflammation Infection (bacteria and viral parasites) and microbial toxin. Trauma (blunt and penetrating) Physical and chemical agents, thermal injury, e.g burns or frostbite, some environmental chemicals. Tissue necrosis (from any cause) Foreign bodies (splinters). Immune reaction (also called hypersensitivity reaction)

Causes of Chronic Inflammation Persistent infection: by certain microorganism, tubercle bacilli, treponema pallidum and certain viruses, lung and parasites. These organism causes delayed hypersensitivity. Some time a granulomatous reaction occurs. Prolonged exposure to potentially toxic agent: Exogenous: particulate silica- causes silicosis Endogenous: causes atherosclerasis.

3. Autoimmunity: Immune reaction develops against the individual’s own tissues, leading to autoimmune diseases, such as rheumatoid arthritis and lupus erythematosus.

Exudation The escape of proteins rich fluid and blood cells (predominantly leukocytes) from the vascular system to interstitial tissue or body cavities is known as exudation.

Exudates It is an inflammatory extra vascular fluid that has a high protein concentration, much cellular debris and specific gravity above 1.020. it is due to normal permeability of small blood vessels in the area of injury.

Benefits of Exudates Fluid exudates: Dilution of irritant substances. Exudates carry inflammatory cells & natural anti-bacterial substances like complement, specific immunoglobulin. Drugs & antibiotics appear at the site of action from the circulation through the exudates. It contain fibrin which has 3 main functions It forms an union between the cut/damaged tissue It may form a barrier against bacterial invasion It aids phagocytosis 5. Nutrition to the greatly increased cells 6. Low of pH due to lactic acid formation (by injured cells & nerves). So inhibits bacterial growth. 7. Promotion of immunity: by carrying Ag to local lymphnode and including immune response

Tissue exudates neutrophils, macrophages- ingest foreign particles, bacteria &cell debris. B lymphocytes- secrets Ig

Function of exudates in Inflammation Dilution of irritant substances. Exudates carry inflammatory cells & natural anti-bacterial substances like complement, specific immunoglobulin. Drugs & antibiotics appear at the site of action from the circulation through the exudates. It contain fibrin which has 3 main functions- It forms an union between the cut/ damaged tissue. It may form a barrier against bacterial invasion. It aids phagocytosis. 5, 6 and 7 are same. 8. Pain production by increasing the tension/ pressure on nerve endings.

Acute Inflammation Fate of acute inflammation: Complete resolution: Resolution means the complete return to normal of a tissue following acute inflammation. Usually it occurs- When the injury is limited and short lived. When there has been a little tissue damage. 2. Healing by connective tissue replacement: There is a substantial tissue destruction Inflammation occurs in the tissue that do not regenerate. There is abundant fibrin exudation

Chronic Inflammation If causative agent persists of there is interference of repair. Clinical Manifestation: Tissue Destruction: induced by persistent offending agent or inflammatory cells. Necrosis of the tissue takes place. Necrotic tissue can perpetuate the inflammatory cascade through the activation of kinin, coagulation complement, dying cells also liberate uric acid.

Fibrosis is another manifestation: it takes and whole of the tissue become fibrotic leading to disfiguring of scar, intestinal obstruction, decrease motility of joints.

Systemic effects of inflammation Fever Increasing acute phase protein Leukocytosis Manifestation of acute phase response- Increase BP and pulse Decrease sweting Chills, anorexia 5. Sepsis

Beneficiary effects of inflammation Without inflammation, infection would remain unchanged Without inflammation wound would never heal Injured tissue and organ might remain as permanent defect.

Harmful effects It may lead to disfiguring scar Formation of fibrous bands may limit the mobility of a joint. Formation of large scar tissue in an organ, may impair the function of a organ. Immune mediated hypersensitivity reaction may cause generalized inflammation leading to massive exudation and shock. Leukocyte products released causes endothelial cell injury and tissue damage.

Pus It is inflammatory exudates consisting of leukocytes (mostly neutrophils), necrotic cells and edema fluid. Composition of Pus: Dead and dying leukocyte Inflammatory exudates: edema fluid and fibrin Living or dead organism.