Pathology Of Inflammation (Cont.) PDF

Pathology of Inflammation (cont.) By Prof. Mie Ali Prof. Mona Younis Pathology department Faculty of Medicine – Mansoura University & HUE Morphology of Acute inflammation Naked eye picture (Cardinal signs) o...

Pathology of Inflammation (cont.) By Prof. Mie Ali Prof. Mona Younis Pathology department Faculty of Medicine – Mansoura University & HUE Morphology of Acute inflammation Naked eye picture (Cardinal signs) of acute inflammation 1) Redness due to V.D. 2) Hotness due to V.D. and increased blood flow. 3) Swelling due to presence of inflammatory exudate. 4) Pain and Tenderness due to: **pressure of exudate on the sensory nerves. ** release of Bradykinin in inflammatory area. 5) Loss of function due to pain & tissue damage. Microscopic picture of acute inflammation 1)Necrotic damaged tissues and degenerated cells. 2) The arterioles, venules and capillaries are dilated and filled with blood. 3) Fluid exudate observed by separation of tissues and pale staining of its fibers + fibrin. 4) Cellular exudate mainly neutrophils (24-48h) and macrophages (after 48h). General (systemic) reactions of acute inflammation 1) Fever (pyrexia): due to release IL-1 & TNF either from the bacteria or leucocytes. It Affects the heat regulating center in the brain ---- Disturb the optimum temperature of bacterial living but cause harm to body tissue. 2) Leukocytosis: Increase leukocytic count due to stimulation of the bone marrow by IL-1 & TNF. 3) Loss of appetite and weight: due to increased catabolism and toxins. Types of acute inflammation 1) Acute suppurative inflammation: Associated with pus formation 2) Acute non-suppurative inflammation: NOT associated with pus formation Acute suppurative inflammation  Acute suppurative inflammation * It is the severest form of acute inflammation. * Caused by strong pyogenic bacteria: 1. Staphylococcus aureus. 2. Streptococcus haemolyticus.  How the pus is formed?? Mechanism of suppurative inflammation 1- Strong pyogenic bacteria causes marked necrosis with excess chemical mediators. 2- Attraction of a large number of neutrophils that die due to high virulence of bacteria. 3- Dead neutrophils (pus cells) release their enzymes which liquify necrotic tissue & fibrin. 4- The liquified material mixed with pus cells & fluid exudate to form “pus”.  Types of Acute suppurative inflammation A- Localized: Caused by staphylococci that produce coagulase enzyme leads to fibrin coagulation and help localization : 1- Abscess: irregular cavity containing pus, occur anywhere but commonly in subcutaneous tissue. 2- Furuncle (Boil): small abscess related to hair follicle, commonly in hairy parts as face, axilla 3- Carbuncle: multiple communicating suppurative foci in the skin and subcutaneous fat that discharge pus through multiple openings, common in diabetics Types of Acute suppurative inflammation B- Diffuse: Caused by streptococci that produce fibrinolysin enzyme that dissolve fibrin and help spread e.g. Cellulitis, suppurative appendicitis Acute non-suppurative inflammation  Acute non-suppurative inflammation Excess erythrocytes Excess fluid exudate Excess necrosis Hemorrhagic Serous Serofibrinous Catarrhal Necrotizing Membranous Allergic  1) Haemorrhagic inflammation Acute non-suppurative inflammation characterized by excessive RBCs in the exudate due to vascular damage. e.g. infection by meningococci.  2) serous inflammation Def: Acute non-suppurative inflammation characterized by excess watery fluid exudate that is poor in fibrin e.g. ** skin blister after burn with watery vesicles. ** skin vesicles due to viral infection (herpes simplex).  3) Serofibrinous inflammation *Def: Acute non-suppurative inflammation with excess fluid exudates rich in fibrin. *Site: Inflammation of serous membranes (pleura, peritoneum and pericardium).  4) catarrhal inflammation Acute non-suppurative inflammation of the mucous membrane with excess mucus secretion e.g. Catarrhal rhinitis (common cold).  5) allergic inflammation Acute non-suppurative inflammation characterized by a fluid exudate rich in eosinophils. It occurs in cases of allergic reaction. e.g. Bronchial asthma.  6) pseudomembranous inflammation It is acute non-suppurative inflammation of the mucous membrane characterized by formation of a false membrane. It is caused by bacteria with non-invasive power but produce powerful exotoxin that causes necrosis of the mucous membrane and replaced by false membrane e.g. * Laryngeal mucosa in Diphtheria. * Colonic mucosa in Bacillary dysentery.  7) necrotizing inflammation Acute non-suppurative inflammation characterized by extensive necrosis e.g. oral mucosa in debilitated malnourished children.