INFLAMMATION By Dr. Gehan Mohamed Dr. Abdelaty Shawky 1

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. 2

* 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 red cells i.e. sanguinous. * Complications: 1.Acute lymphangitis and lymphadenitis. 2.Septic thrombophlebitis causing pyaemic abscesses. 3.Septicaemia. 3

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II. NON-SUPPURATIVE INFLAMMATION 1. Catarrhal 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. 6

2. Membranous Inflammation (Pseudomembranous) Severe acute inflammation characterized by the formation of a pseudomembrane on the affected surface formed of necrotic cells, fibrin threads, leucocytes. e.g. diphtheria and bacillary dysentery. 7

3. Fibrinous Inflammation: 3. Fibrinous Inflammation: Characterized by an exudate rich in fibrinogen e.g. lobar pneumonia. 4. Serofibrinous Inflammation: 4. Serofibrinous Inflammation: It involves serous sacs as pleura, peritoneum and pericardium. Characterized by excess serous exudates in the sac and deposition of fibrin on the surface. 8

9 Serofibrinous Inflammation:

10 Serofibrinous Inflammation:

5. Haemorrhagic Inflammation: 5. Haemorrhagic Inflammation: Characterized by cellular exudate rich in the red blood cells due to vascular damage e.g. smallpox. 11

6. Necrotizing Inflammation: 6. Necrotizing Inflammation: Acute inflammation characterized by marked tissue necrosis. 7. Allergic Inflammation: as urticaria. It is an antigen antibody reaction characterized by abundant fluid exudates and eosinophils. 12

CHRONIC INFLAMMATION 13

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. 14

4. The small arteries and arterioles show thickening of the walls and narrowing of the lumens called end arteritis obliterans. 5. The inflammatory fluid exudate is scanty. 6. The inflammatory cellular exudate consists of lymphocytes, plasma cells, macrophages and foreign-body giant cells (chronic infl. Cells). 7. Fibrosis. 15

Types of Chronic inflammation: 1. Chronic non-specific inflammation: Different irritants produce inflammatory reactions of the same microscopic picture e.g. chronic abscess and chronic tonsillitis. 2. Chronic specific inflammation: Each irritant or organism produces a characteristic microscopic picture called granuloma e.g. tuberculosis, bilharziasis and leprosy 16

Differences between acute and chronic inflammation 17

Chronic inflammation Acute inflammation Item Slow and gradual Rapid and sudden Onset ProlongedShortDuration Slight or absent Present Vascular phenomena Slight or absent Present Cardinal signs -Plasma cells, lymphocytes, macrophages, giant cells, fibroblasts -Few thick walled narrow lumen(end arteritis oblitrans) -Polymorphs, pus cells, macrophages -Numerous, thin walled, dilated and filled with blood Mic. Changes Cells Cells Blood vessels Blood vessels 18

Granuloma * Definition: Chronic specific inflammation characterized by focal accumulation of large number of chronic inflammatory cells to form tumor like mass. 19

* Types: 1. Infective granuloma 1. Bacterial as TB, leprosy & syphilis 2. Parasitic as bilharziasis & leishmaniasis 3. Mycotic (fungus) as madura foot, actinomycosis 4. Viral as granuloma inguinale 2. Non-infective granuloma As silicosis, asbestosis and foreign-body granuloma. 3. Unknown cause Sarcoidosis, crohns disease 20

* 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 21

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. 22

23 Schistosomiasis

Pulmonary Tuberculosis 24

25 Pulmonary Tuberculosis

26 Thanks