Inflammation Lecture 7 PDF

Pathology of TYPES OF ACUTEINFLAMMATION BY Dr. Mie Ali Mohamed Profesor of pathology Mansoura universty Learning Outcomes Classification of acute inflammation Types, sites and pathogenesis of acute suppurative inflammation Course, fate and complications of an acute ab...

Pathology of TYPES OF ACUTEINFLAMMATION BY Dr. Mie Ali Mohamed Profesor of pathology Mansoura universty Learning Outcomes Classification of acute inflammation Types, sites and pathogenesis of acute suppurative inflammation Course, fate and complications of an acute abscess Types, nature and examples of acute non suppurative inflammation 1) Suppurative (Purulent – septic - Pyogenic) inflammation: Associated with pus formation 2) Non-Suppurative inflammation. NOT associated with pus formation  1) Acute Suppurative (Purulent - Septic - Pyogenic) inflammation A- Localized (Caused by staphylococcus Aureus) that produce coagulase enzyme leads to fibrin coagulation and deposition that help localization : 1- Abscess. 2- Furuncle (Boil) 3- Carbuncle. B- Diffuse: (caused by streptococci) that produce hyalurinidase and streptokinase (fibrinolysin) that dissolve fibrin and help spread e.g. Cellulitis, suppurative appendicitis etc.  Mechanism of suppuration (Pus formation) severest form caused by strong pyrogenic bacteria as staphylococcus aureus and streptococcus haemolyticus (1) Strong pyogenic Bacteria cause marked necrosis (2) Attraction of large number of neutrophils that die due to high virulence of bacteria (3) Presence of sufficient amount of proteolytic enzymes Mainly produced by dead neutrophils (= pus cells) and to less extent by necrotic tissue make liquefaction of of necrotic tissue and fibrin Liquefied material mixed with pus cells and fluid exudate to form pus  1) ABSCESS Definition:A localized suppurative inflammation resulting in the formation of an irregular pus-containing cavity. Site: It can occur anywhere commonly subcutaneous (commonest) or deep organs Pathogenesis: Early the abscess shows two zones, a central necrotic zone surrounded by a zone of acute inflammation containing large number of neutrophils then abscess then shows three zones: a- Central necrotic core. b- Mid zone containing pus, the abscess cavity usually formed by 48 hours. c- Peripheral zone of inflamed tissue called pyogenic membrane.  Course of an abscess 1. The abscess enlarges by further necrosis and liquefaction of the surrounding inflamed zone until the staphylococci produce the coagulase enzyme which helps fibrin formation that localizes the inflammation. 2. A subcutaneous abscess appears as localized tender swelling covered by red edematous skin with opaque yellow center. 3. The covering epidermis may undergo necrosis and separates 4. (A slough is a separated necrotic tissue) and the pus is evacuated. an ulcer is formed. 5. An internal abscess as lung, liver or kidney opens in a hollow organ as in bronchi, ureter, intestine Early and established abscess M/E  Course and Fate of an abscess 1- Small abscess: pus may be absorbed and followed by healing. 2- Large abscess: Pus is very slowly absorbed & its high osmotic pressure absorb water & increase in size → throbbing pain. If not surgically evacuated, pointing & rupture occur (spontaneous evacuation) on the skin or hollow organs of abscess of internal organs followed by healing by 2ry intention. * Complications of acute abscess: A) Complications of spontaneous evacuation & non-healing: 1- Ulcer 2- Sinus 3- Fistula 4- Hemorrhage B) Complications of Healing: Keloid (excessive projecting scar). C) If not evacuated (Chronic Abscess): surrounded by fibrosis, the pus dries with addition of cholesterol crystals & dystrophic calcification may occur. e.g. chronic breast abscess. E) Spread of infection: 1- Direct: lead to enlargement of the abscess. 2- Lymphatic: leads to lymphangitis & lymphadenitis. 3- Blood: leads to: - Toxemia: Bacterial toxins circulating in the blood. - Septicemia: large No. of virulent bacteria with their toxins circulating in the blood. - Pyemia: Multiple small abscesses caused by septic emboli derived from septic thrombi due to septic inflammation of a nearby vein (septic thrombophlebitis).  Ulcers Keloid Sinus Fistula  2) Furuncle (Boil) Def: It is small abscess related to hair follicle, sebaceous or sweat gland. Cause: staphylococci. Site: mainly hairy parts as face, axilla. Multiple neighboring boils are called furunculosis.  3) Carbuncle Definition: Acute localized suppurative inflammation forming multiple communicating suppurative foci in the skin and S.C. fat discharging pus through several openings. Cause: staphylococci. Common in diabetes Site: Areas where the skin and S.C. tissue are thick and tough as the back of the neck, scalp and buttocks. Pathology: When bacteria invade S.C. fat it will result in the formation of multiple communicating suppurative foci developing in the same way as the abscess. The open on the surface at multiple points particularly at the base of hair follicles.  Types of acute suppurative inflammation B- Diffuse (Caused by streptococcus hemolyticus): Cellulitis * Def: Acute diffuse suppuration inflammation. * Cause: streptococcus hemolyticus which produces two enzymes: Fibrinolysin (streptokinase) enzyme: Dissolves fibrin. Hyaluronidase enzyme: Dissolves hyaluronic acid of ground substances helping spread of bacteria. Sites: Loose connective tissue as areaolar tissue of the orbit, scrotum and wall of the appendix …. etc. Characters of pus of streptococcal pus Thin and bloody Contains many sloughs (necrotic depris) due to more necrosis * Complications: - Lymphatic spread: leads to acute lymphangitis and lymphadenitis. - Blood spread: leads to septicemia and pyemia. Acute diffuse suppurative appendicitis  Types of acute inflammation 2) Non-Suppurative inflammation ✓Serous inflammation ✓Serofibrinous inflammation ✓Allergic inflammation ✓Catarrhal inflammation ✓Pseudomembranous ✓Hemorrhagic ✓Necrotizing  1) Serous inflammation * Def: Acute inflammation characterized by excess watery fluid exudate.Poor in fibrin e.g. In skin blister after burn with watery vesicles are seen/ skin vesicles due to viral infection  2) Serofibrinous inflammation Def: Acute inflammation characterized by the formation of excess fluid exudate rich in fibrin Site: Inflammation in serous membranes as pleura; peritoneum and pericardium Fibrinous pericarditis  3) Allergic inflammation Def: Acute non suppuratine inflammation characterized by fluid exudate rich in eosinophil's It occurs in case of hypersensitivity eg urticaria, bronchial asthma, allergic rhinitis, contact dermatitis Urticaria  4) Catarrhal inflammation Def: Mild acute inflammation of the mucous membranes characterized by excess mucous secretion. Sites: Catarrhal rhinitis  5) pseudomembranous inflammation * Def: acute inflammation characterized by formation of pseudomembrane consisting of fibrin, desquamated epithelium and inflammatory cells * Cause: - Diphtheria - Bacillary dysentery caused by Shigella bacilli. Complications Toxemia most common Suffocation by detached membranes as in Diphtheria  6) Hemorrhagic inflammation Def: Acute inflammation characterized by vascular damage and hemorrhage in the exudate as in meningococci 7) Necrotizing inflammation Def: It is acute inflammation characterized by extensive tissue necrosis e.g. Oral mucosa in debilitated malnourished children Acute inflammation is divided to two main category according to the presence or absence of pus Acute suppurative inflammation includes the localized types (absecess, boil,furuncle) and diffuse type (cellulties; acute diffuse suppurative inflammation) Summary & Wrap up Acute non suppurative inflammation includes many types according to the nature of the exudate  References Robbin’s pathologic basis of disease PATHMAX:http://www.pathmax.com/ Special pathology book of pathology department – Mansoura University