Acute Inflammation: Causes, Types, and Outcomes PDF

Acute inflammation Assistant a Professor R.F. Zibirov  Inflammation a defensive process in living body initiates against local tissue damage. It takes the form of a complex reaction of blood vessels, plasma components, blood cells and components of connectiv...

Acute inflammation Assistant a Professor R.F. Zibirov  Inflammation a defensive process in living body initiates against local tissue damage. It takes the form of a complex reaction of blood vessels, plasma components, blood cells and components of connective tissue. The unique feature of the inflammatory process is the reaction of blood vessels, leading to the accumulation of fluid and leukocytes in extravascular tissues.  Purposes: ⚫ A protective response: ⚫ 1. to dilute, localize and destroy the injurious agent ⚫ 2. to limit tissue injury 3. to restore the tissue towards normality  Etiology of inflammation 1. Physical agents: excessive heating or cooling, mechanical trauma, ultraviolet or ionising radiations. 2. Chemical agents (both inorganic and organic). 3. Microbiological agents: (bacteria, fungus, viruses) 4. Immune reactions : hypersensitivity reactions. 5. Tissue necrosis from any cause. Several molecules released from necrotic cells are known to elicit inflammation; these include uric acid, a purine metabolite; adenosine triphosphate.  Acute Inflammation: Rapid local response of living tissue to injury Lasts for minutes to a few days Extravascular accumulation of protein rich fluid and leucocytes, predominantly Neutrophils, i.e., Exudative lesion Stereotype, i.e., wide variety of agents share the same basic features  Chronic Inflammation: Persists for weeks to months Extravascular accumulation of lymphocytes and macrophages Tissue destruction and attempts to healing by proliferation runs simultaneously, i.e., Proliferative lesion Not stereotype  Clinical features of acute inflammation There are 5 cardinal signs of inflammation as: rubor (reddening) tumor (swelling) calor (warmth) dolor (pain) functio laesa (loss of function).  PATHOGENESIS OF INFLAMMATION There are numbers of phases in acute inflammatory reaction: Damage (alteration) as a result of the action of etiologic factors (accompanied by release of mediators of inflammation). Exudation (vascular and cellular events). Proliferation and differentiation of cells.  Margination of leucocytes, endothelial adhesion and leucocyte emigration. PECAM = platelet/endothelial cell adhesion molecule; ICAM intercellular adhesion molecule.  TYPES OF EXUDATIVE INFLAMMATION: Acute inflammation is accompanied by exudate formation. Exudate is an inflammatory extravascular fluid that has a high protein concentration, much cellular debris, and a specific gravity above 1.020. It implies significant alteration in the normal permeability in small blood vessels in the area of injury. Transudate is a fluid with low protein content and spesific gravity of less than 1.012. It is essetially an ultrafiltrate of blood plasma and result from hydrostatic imbalance across the vascular endothelium. In this situation, the permeability of the endothelium is normal.  TYPES OF EXUDATIVE INFLAMMATION Depending upon the composition of exudates the following types of exudative inflammation are divided: 1) serous inflammation, 2) catarrhal inflammation (depend from localisation) 3) fibrinous (pseudomembranous) inflammation, 4) purulent inflammation, 5) hemorrhagic inflammation, 6) mixed inflammation.  SEROUS INFLAMMATION This type of acute inflammation characterized by copious fluid exudation but emigration of leukocytes and escape of red cells are minimal. Its occur in serous membranes (such as the pleura, pericardium, peritoneum, joints), in parenchyma of organs (such as serous hepatitis, nephritis, myocarditis. Typical examples of serous inflammation are blister formation as reaction of skin at burn and herpes virus infection.  CATARRHAL INFLAMMATION It is acute inflammation of a mucous membrane a respiratory and gastrointestinal tracts and accompanied by glandular secretion. Etiology: Bacterial, viral, physical and chemical tissue injury. Morphology: The mucosa and submucosa appear reddened and swollen, with a slight degree of lymphocytic infiltration. Part of the surface epithelium may die, and epithelial tissue may be sloughed off. As a result, the mucous exudate may contain epithelial cells.  CATARRHAL INFLAMMATION Examples: — Acute rhinitis — Acute catarrhal bronchitis; — Enteritis.  Serous and catarrhal inflammation Serous inflammation of laryngs Catarrhal inflammation of the nasal mucosa goblet cell hyperplasia  Fibrinous inflammation Definition: Acute inflammation with exudation of fibrinogen-containing serum. It's occur in serous membranes (fibrinous pleuritis, fibrinous pericarditis, fibrinous peritonitis) and in parenchyma of inner organs (lobar pneumonia in the gray hepatization stage). Etiology: - Bacteria. —Chemical and toxic tissue injury; — Excretion of toxic metabolites (uremic toxins); Examples: fibrinous inflammation of pharynx or larynx; bacillary dysentery of colon.  Fibrinous inflammation Several forms are differentiated based on the relation of fibrin exudation and necrosis: 1. Fibrinous croupous form. It is acute inflammation in which a wide area of fibrinous exudate forms an easily removable pseudomembrane, which is limited to the mucosal epithelium. Pathogenetic chain reaction: the inflammatory necrosis only involves part of the mucosa. The submucosa remains largely intact.  Fibrinous inflammation Examples of fibrinous croupous form inflammation: — Amebic dysentery — Croupous pneumonia.  Fibrinous inflammation Fibrinous diphtheritic type it is acute inflammation which extends into the submucosa and fibrinous exudate forms of an adhesive pseudomembrane that can only be forcibly removed (diphtheric pseudomembrane). Pathogenetic chain reaction: the inflammatory exudate extends to the submucosa, causing erosion of the submucosal vessels and resulting in the escape of fibrinous exudate over a wide area.  Fibrinous inflammation Examples: — Diphtheric inflammation on mucous membrane of uterus, vagina, stomach and intestine (at dysentery). — Antibiotic enterocolitis  Fibrinous inflammation Fibrinous pericarditis ("hairy heart”) Croupous tracheitis Inflammatory exudate islands of epithelium remain unaffected  Fibrinous pericarditis ("hairy heart”) Fibrin  PURULENT INFLAMMATION General definition: inflammation with exudates consisting primarily of neutrophils and cellular debris (detritus). Etiologiy: pyogenic pathogens such as Staphylococci, Streptococci. Examples of this type of inflammation are purulent meningitis caused by meningococci, staphylococci purulent pneumonia.  PURULENT INFLAMMATION There are three types of acute purulent inflammation: 1. Abscess is accumulation of pus in a confined space. Examples: — Pulmonary abscesses occur after pulmonary infarction or lobar pneumonia; — Cerebral abscesses occur following open cranial and cerebral trauma; — Kidney abscesses may spread from purulent pyelonephritis;  PURULENT INFLAMMATION — Liver abscesses may spread from a suppurative inflammation in the region drained by the portal vein, such as amebic dysentery. It may also spread from suppurative cholangitis; — Septicopyemic abscesses occur focally in the subpleural lung, as medullary strip lesions in the kidney, as punctate subendocardial lesions in the heart, and as punctate subcapsular lesions in the liver.  PURULENT INFLAMMATION 2. Phlegmon is the diffuse purulent inflammation. Examples: — Muscular phlegmon; — Mediastinal phlegmon; — Phlegmon of the walls of hollow organs (such as phlegmonous cholecystitis, appendicitis).  PURULENT INFLAMMATION 3. Empyema is accumulation of pus in body cavity. Pathogenesis: an empyema usually occurs where a suppurative inflammation of an organ breaks through into an adjacent cavity. Examples: — Pericardial, peritoneal, and pleural empyema ; — Gallbladder and appendiceal empyema; — Pyosalpinx (pus in the uterine tube); — Hypopyon (pus in the anterior chamber of the eye).  PURULENT INFLAMMATION Peritoneal empyema Pulmonary abscesses purulent pneumonia; accumulation of the neutrophils in alveolar space Abscess in the myocardium; center is a collection of bacteria that are the cause for this abscess. abscess in the lung. The alveoli in that area have been destroyed.  HEMORRHAGIC INFLAMMATION Definition: Acute inflammation involving microvascular injury with massive diapedesis, producing an exudate with a high erythrocyte. Morphology: The inflamed area is usually necrotic and filled with blood. Etiologic factors include: — bacterial exotoxins and endotoxins; — viral cytopathic effect on endothelium; Examples: It observed at influenza, pneumonic plague and anthrax.  HEMORRHAGIC INFLAMMATION Plague lymphadenitis Hemorrhagic pneumonia  MIXED INFLAMMATION The mixture of secretion and exudate may consist of a mixture of mucus and pus; the inflammation, initially catarrhal, thus becomes mucopurulent. Catarrhal bronchitis is seen in mild influenza is often complicated by bacterial infections, with similar effects. OUTCOMES OF ACUTE INFLAMMATION  HEALING Tissue injuries associated with inflammation are eventually followed by some form of healing. Removal of inflammatory and necrotic cellular debris must precede any such healing. Resolution is to restore the tissue to its normal state when tissue loss after injury absent. Regeneration the lost tissue or part in which the lost cells are replaced by identical one. Organization (repair by scar formation) is replacement of injuried tissue by scar(connective) tissue  NEGATIVE SIDES OF INFLAMMATION 1. Inflammatory reactions underlie life-threatening hypersensitivity reactions to insect bites, drugs, and toxins as well as some, of the common chronic diseases such as rheumatoid arthritis, atherosclerosis, and lung fibrosis. 2. Repair by fibrosis may lead to disfiguring scars or fibrous bands that cause intestinal obstruction or limit the mobility of joints. 3. Several chronic infectious diseases are associated with development of malignancies. For example, schistosomiasis of the urinary bladder leads to squamous cell carcinoma of that organ. Ulcerative colitis are at higher risk for adenocarcinoma in this organ. Thank you for attention