Inflammation

Definition of inflammation, Causes, Signs of inflammation, Types of inflammation, Triple response, Phagocytosis, Transudate or Exudate, Difference between transudate and exudate, Granuloma and Granulomatous inflammation

1. Inflammation Dr. Bhawna MPT (Pediatric)

2. Definition Inflammation is defined as the local response of living mammalian tissues to injury from any agent. It is a body defense reaction.

3. Causes Infective agents Immunological agents Physical agents Chemical agents Inert material

4. Infective agents

5. Immunological agents Cell mediated and antigen antibody reactions.

6. Physical agents

7. Chemical agents

8. Inert material Foreign bodies

9. Signs of inflammation Rubor (redness) Tumor (swelling) Calor (heat) Dolor (pain) Functio laesa (loss of function)

10. Rubor (redness)

11. Tumor (swelling)

12. Calor (heat)

13. Dolor (pain)

14. Types of inflammation Classified as acute and chronic. Acute inflammation Chronic inflammation

15. Acute inflammation Short duration (lasting less than 2 weeks ) Represents the early body reactions Resolves quickly Main features of acute inflammation- Accumulation of fluid and plasma at the affected site Intravascular activation of platelets Neutrophils as inflammatory cells

16. Two major components of acute inflammation: Vascular stages • leads to an increased in blood flow • changes in the small blood vessels of the microcirculation Cellular stages • leads to the migration of leukocytes from the circulation • their activation to eliminate the injurious agent

17. Vascular stages characterized – 1. Haemodynamic changes 2. Altered vascular permeability Haemodynamic changes momentary vasoconstriction (seconds) vasodilatation – arterioles, venules (minutes) increased capillary permeability consequenses : •swelling •mediator release •increased viscosity •Increased blood clotting (hours)

18. Triple response The features of Haemodynamic changes in inflammation are best demonstrated by the Lewis experiment. Lewis induced the changes in the skin of inner aspect of forearm by firm stroking with a blunt point. The reaction so elicited is known as triple response or red line response consisting of the following : Red line appears within a few seconds after stroking and is due to local vasodilatation of capillaries and venules . Flare is bright reddish appearance or flush surrounding the red line and results from vasodilatation of the adjacent aterioles . Wheal is the swelling or oedema of the surrounding skin occurring due to transudation of fluid into the extra vascular space.

19. Cellular stages The cellular stage of acute inflammation is marked by changes in the endothelial cells lining the vasculature and movement of phagocytic leukocytes into the area of injury or infection. The cellular phase of inflammation consists of 2 processes : Exudation of leucocytes Phagocytosis

20. Exudation of leucocytes Changes in the formed elements of blood Rolling and adhesion Emigration Chemotaxis

21. Phagocytosis Phagocytosis of the microbe by polymorph macrophages ( neutrophils and macrophages) involves following 3 steps. Recognition and attachment Engulfment Killing and degradation

22. Chronic inflammation Chronic inflammation is a longer duration and occur after delay. Chronic active inflammation , is the type of chronic inflammation in which during the course of disease there are acute exacerbation of activity. Chronic inflammation is defined as prolonged process in which tissue destruction and inflammation occurs at the same time.

23. Chronic inflammation may occur by one of the following 3 ways : Chronic inflammation following acute inflammation Recurrent attacks of acute inflammation Chronic inflammation starting de novo

24. Transudate  or  Exudate The closed cavities of the body—namely, the  pleural ,  pericardial , and  peritoneal  cavities—are each lined by two membranes,  visceral  membrane and  parietal  membrane. There is a small amount of fluid between the membranes that is an ultrafiltrate of plasma. When the production and reabsorption of the ultrafiltrate is not balanced, fluid may accumulate, resulting in effusion. Effusions may be classified as  transudate  or  exudate .

25. Difference between transudate and exudate Transudate Exudate Filtrate of blood plasma without changes in endothelial permeability Non-inflammatory edema Low protein content Glucose content same as plasma Specific gravity is low pH >7.3 Few cells, mainly mesothelial cells and cellular debris Eg . Oedema in congestive heart failure Oedema of inflammed tissue associated with increased vascular permiability Inflammatory oedema High protein content Glucose content is low High specific gravity pH <7.3 Many cells, inflammatory as well as parenchymal Eg . Plurent exudate such as pus

26. Granuloma

27. Granulomatous inflammation Granuloma is defined as a circumscribed, tiny lesion, about 1mm in diameter, composed predominantly of collection of modified macrophages called epithelial cells, and rimmed at the periphery by lymphoid cells.

28. Composition of granuloma Epithelial cells Multinucleated gaint cells Lymphoid cells Necrosis Fibrosis

29. Necrosis the death of most or all of the cells in an organ or tissue due to disease, injury, or failure of the blood supply

30. Fibrosis the thickening and scarring of connective tissue, usually as a result of injury