Lecture (4) Princible Of Disease (باثولوجي) PDF

INFLAMMATION Dr Hanan Hosny 2024/ 2025 Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology  Cell injury Acute inflammation Chronic Resolution inflammation Dr.Hanan Hosny * Pathology...

INFLAMMATION Dr Hanan Hosny 2024/ 2025 Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology  Cell injury Acute inflammation Chronic Resolution inflammation Dr.Hanan Hosny * Pathology  What is Inflammation? A reaction of a living tissue & its micro- circulation to a pathogenic insult. It is a protective mechanism designed to get rid of organism initial cause cell injury  It serves healing mechanisms to the site of injury Dr.Hanan Hosny * Pathology Characteristic of acute Inflammation: Early (almost immediate) response of a tissue to injury. It is nonspecific. May be regarded as the first line of defense against injury Dr.Hanan Hosny * Pathology Etiologies (Causes): 1. Microbial infections: bacterial, viral, fungal, etc. 2. Physical agents: burns, trauma (cuts), radiation 3. Chemicals: drugs, toxins, or caustic substances like battery acid. 4. Immunologic reactions: rheumatoid arthritis. Dr.Hanan Hosny * Pathology Cardinal Signs of Inflammation  Red : Hyperaemia.  Hot : Hyperaemia.  Pain : Nerve, Chemical mediators.  Swelling : Exudation  Loss of Function: Pain Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology Time course Acute inflammation: Less than 48 hours Chronic inflammation: prolongation of inflammation (weeks, months, years). Cell type Acute inflammation: Neutrophils Chronic inflammation: Mononuclear cells (Macrophages, Lymphocytes, Plasma cells). Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology  Mechanism of Inflammation 1- Vascular role 2- Cellular role 3-Chemical role Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology  Mechanism of Inflammation 1- Vascular Role: (Slowing of the circulation)  The first change in the microcirculation is a transient and insignificant vasoconstriction,  which is then followed by marked, active dilation of arterioles, capillaries  Outpouring of albumin rich fluid into the extravascular tissues results in the concentration of RBCs in small vessels and increased viscosity of blood. Dr.Hanan Hosny * Pathology  1.Vasodilatation: Increased blood flow (redness and warmth). 2.Exudation – Edema : swelling, pain & loss of function). 3.leukocytes accumulation Dr.Hanan Hosny * Pathology  Edema:  Lymphatics are responsible for draining edema. Edema: An excess of fluid in the interstitial tissue or cavities; it can be either a transudate or an exudate Dr.Hanan Hosny * Pathology Transudate: An ultra filtrate of blood plasma, low protein content ( mostly low albumin) Exudate: A fluid rich in protein and cellular elements that oozes out of blood vessels due to inflammation and is deposited in nearby tissues. Dr.Hanan Hosny * Pathology 2- Cellular Role in Inflammation: Neutrophil mainly is the predominant cell. Divided into 3 steps  Margination: rolling, and adhesion to endothelium  Migration: toward a chemotactic toward source of tissue injury.  Phagocytosis: engulfing of infection agent and dead cells Dr.Hanan Hosny * Pathology  3-Chemical Mediators: Chemical substances synthesised or released and mediate the changes in inflammation.  Histamine by mast cells : vasodilatation.  Prostaglandins : Cause pain & fever.  Bradykinin : Causes pain. o Chemokines: attractants for specific types of leukocytes Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology Acute Inflammation Bronchopneumonia Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology  Cellulitis - It is an acute diffuse suppurative inflammation of skin caused by streptococci. -which secrete hyaluronidase & streptokinase enzymes that dissolve the ground substances and facilitate the spread of infection. - Sites: - Areolar tissue; orbit, pelvis, … - Subcutaneous tissue Dr.Hanan Hosny * Pathology  Abscess formation: "A localized collection of pus (superlative inflammation) appearing in an acute or chronic infection, and associated with tissue destruction, and swelling. Pus contains: purlent exudate,rich in neutrophil,and dead cells Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology  Chronic Inflammation Definition: Inflammatory response of prolonged duration (weeks – months – years) in which active: - inflammation - tissue injury - with attempts to repair coexist together. Dr.Hanan Hosny * Pathology - 1.Persistent CAUSES OF CHRONIC acuteINFLAMMATION: inflammation: - unresolved acute inflammation or infection. For example: pneumonia may proceed to lung Abscess Dr.Hanan Hosny * Pathology 2. Starts as chronic inflammation:  Mycobacterium (Tuberculosis)  Syphilis  Leprosy  Viral (hepatitis C) Dr.Hanan Hosny * Pathology 3- Autoimmune mediated Inflammatory disease: For example:  Rheumatoid arthritis  Systemic lupus Dr.Hanan Hosny * Pathology 4- Prolonged exposure to toxic material: Endogenous: elevated of plasma lipids causing atherosclerosis. Exogenous: Asbestos Silica Dr.Hanan Hosny * Pathology  Chronic Inflammation Acute Inflammation Normal Dr.Hanan Hosny * Pathology  Types of chronic Inflammation 1-Granulomatous Chronic 1 Inflammation 2- Non- Granulomatous (non- 2 specific) Chronic Inflammation Dr.Hanan Hosny * Pathology  Granulomatous Inflammation Granulomatous inflammation is a distinctive pattern of chronic inflammation that occur in a limited number of infectious and some noninfectious conditions. Immune reactions are usually involved in the development of granulomas. A granuloma is a cellular attempt to contain an offending agent that is difficult to eradicate. Dr.Hanan Hosny * Pathology A granuloma is a focus of chronic inflammation consisting of: a microscopic aggregation of macrophages that are transformed into epithelium-like cells (epitheloid cells), surrounded by lymphocytes. Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology Epitheloid cell:(Activated Macrophage) Epithelial like cell appearance Modified macrophages, with hazy outline Pale pink granular cytoplasm Oval or elongated nucleus They are weakly phagocytic May fuse to form giant cells Dr.Hanan Hosny * Pathology  Giant Cells -Epithelioid cells fuse to form giant cells in the periphery or sometimes in the center of granulomas. They have a large cytoplasm containing 20 or more small nuclei arranged either:  Peripherally (Langhans-type giant cell- horse shoe) or  Haphazardly ( where there is central Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology Haphazard arrangement Langhans' giant this giant cells (arrows) granuloma. Note within central peripherally arranged nuclei in giant cell. collections of nuclei Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology  Examples of Granulomatous Disease Tuberculosis Syphilis Leprosy Fungal infection Parasitic infections(Schistosomiasis) Foreign bodies Sarcoidosis Dr.Hanan Hosny * Pathology Dr.Hanan Hosny * Pathology