Inflammation-3 Lecture Notes PDF

INFLAMMATION-3 Dr.Gehan Abdelmenam  Intended Learning Objectives Recall definition,causes,sites and complication of cellulitis. List types of non suppurative inflammation with example for each one. Describe characters and Types of Chronic inflammation. Recall de...

INFLAMMATION-3 Dr.Gehan Abdelmenam  Intended Learning Objectives Recall definition,causes,sites and complication of cellulitis. List types of non suppurative inflammation with example for each one. Describe characters and Types of Chronic inflammation. Recall definition,histopathology and types of granuloma.  Cellulitis * Definition: Acute diffuse suppurative inflammation. * Cause: Streptococcus haemolyticus. The organism produces two enzymes: (1) Fibrinolysin (streptokinase): Dissolves fibrin. (2) Hyaluronidase (spreading factor): Dissolves hyaluronic acid of ground substance helping spread of bacteria and its toxins.  * Sites: Loose connective tissue as subcutaneous tissue, scrotum, orbit and wall of the appendix. * Characters: 1. Failure of localization because of absence of fibrin. 2. Extensive necrosis. 3. Pus is thin in consistency and may contain many RBCs i.e. sanguinous. * Complications: 4. Acute lymphangitis and lymphadenitis. 5. Blood spread: Septicaemia and toxaemia. Cellulitis  II. NON-SUPPURATIVE INFLAMMATION 1. Catarrhal Inflammation: Mild acute inflammation of the mucous membranes of the respiratory and GIT characterized by excess mucus secretion. e.g. catarrhal rhinitis (common cold), bronchitis,... etc.  2. Pseudomembranous Inflammation Severe acute inflammation characterized by the formation of a pseudo membrane on the affected surface formed of necrotic cells, fibrin threads, leucocytes. e.g. diphtheria and bacillary dysentery. 3. Fibrinous Inflammation: Characterized by an exudate rich in fibrinogen e.g. lobar pneumonia. 4. Serous,fibrinous , serofibrinous Inflammation: It involves skin or serous sacs as pleura, peritoneum and pericardium. Characterized by excess serous exudates in the sac and deposition of fibrin on the surface. 5. Hemorrhagic Inflammation: Characterized by cellular exudate rich in the red blood cells due to vascular damage e.g. -smallpox Small pox -acute hemorrhagic pancreatitis 6. Allergic Inflammation: as urticaria. It is an antigen antibody reaction characterized by abundant fluid exudates and eosinophils.  CHRONIC INFLAMMATION  Chronic inflammation is characterized by the following: 1.The irritant is mild and has a prolonged action. 2. The tissue response is gradual and prolonged. 3. Chronic inflammation may follow acute inflammation or starts as slowly progressing chronic disease as in tuberculosis and syphilis.  4. Histopathologically it shows; End arteritis obliterans (E.A.O) of small arteries. Chronic inflammatory cells include lymphocytes, plasma cells, macrophages. Fibrosis: which is the surest sign of chronicity. Fibrosis E.A.O  Types of Chronic inflammation: 1. Chronic non-specific inflammation: Different irritants produce inflammatory reactions of the same non- specific microscopic picture of chronic inflammation e.g. chronic non-specific cholecystitis. 2. Chronic specific inflammation: Each irritant or organism produces a characteristic microscopic picture called granuloma e.g. tuberculosis, bilharziasis and leprosy  Granuloma * Definition: Chronic specific inflammation forming a tumor –like mass grossly and characterized microscopically by focal accumulation of large number of chronic inflammatory cells.  * Types: 1. Infective granuloma: 1. Bacterial as Tuberculosis, leprosy & syphilis 2. Parasitic as bilharziasis & leishmaniasis 3. Mycotic (fungus) as madura foot 4. Viral as subacute granulomatous thyroiditis 2. Non-infective granuloma: As silicosis, asbestosis and foreign-body granuloma. 3. Unknown cause: * Histopathology of granuloma: Macrophages main bulk of granuloma, made of tissue histiocytes and blood monocytes. Other inflammatory cells as lymphocytes, plasma cells, eosinophils. Granulation tissue. Fibrous tissue. Specific organism or foreign body. Microscopic picture of tuberculous granuloma Foreign body granuloma to suture material (nylon, silk) contains multinucleated giant cells, with haphazardly arranged nuclei. These giant cells are fused macrophages. The foreign body is birefringent, and sometimes may be visible by polarized light in the middle of the granuloma or inside the giant cells.  REFERENCES Robbins and Cotran Pathologic Basis of Disease, 9th edition, 2014 ( Kumar, Abbas, Aster) Robbins Basic Pathology 10th edition, 2017 ( Kumar, Abbas, Aster)