L4- Acute Inflammation Flashcards Preview

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Flashcards in L4- Acute Inflammation Deck (13):
1

Acute inflammation

Non-specific initial reaction to tissue damage

2

Acute inflammation - causes

Tissue death
-Ischaemia
-Trauma
-Toxins
-Chemical insults
-Thermal injury
-Radiation

Infection
-Especially bacterial (‘pyogenic’)

3

Purpose of acute inflammation

Clear away dead tissues

Locally protect from infection

Allow access of immune system components

4

Cardinal signs’ of inflammation

Calor= heat
Dolor= pain
Rubor= redness
Tumor= swelling

5

Components of the acute inflammatory response ...reactions

Vascular reaction - dilatation (=rubor), changes in flow

Exudative reaction - formation of inflammatory exudate (=tumor)

Cellular reaction - migration of inflammatory cells out of vessels

6

Vascular reaction

Microvascular dilatation
Initially flow is increased and then decreased
There is an increased permeability (mediated and non mediated)

Mediated: Histamine, Bradykinin, NO, complement components

Non mediated: Direct damage to endothelium e.g toxins, physical agents

7

Exudative reaction

formation of inflammatory exudate (=tumor)
Protein rich:
-Immunoglobulins
-Fibrinogen

e.g The heart in a case of pericarditis

8

Cellular reaction

Migration of inflammatory cells out of vessels

Accumulation of neutrophils in extracellular space

In severe cases, accumulation of neutrophils, cellular debris and bacteria forms pus
-e.g acute meningitis caused by a pyogenic (=pus forming) bacterial infection

-bronchopneumonia - the airspaces are filled with a neutrophil rich exudate

9

Neutrophils

Produced in bone marrow
Commonest white cell in blood
Increase in acute inflammation
Motile, amoeboid, can move into tissues
Directional chemotaxis
Short lifespan (hours in tissues)

Phagocytic, microbiocidal

10

Steps in a cellular reaction (Migration)

he movement or passage of blood cells, especially white blood cells, through intact capillary walls into surrounding body tissue. Also called migration

Margination --> Rolling- adhesion (pavementing) --> diapedesis

11

Cell derived Mediators of acute inflammation

Prostaglandins
Leukotrienes
PAF
Cytokines (IL1,8; TNFa)
NO
Chemokines
Histamine

12

Plasma derived Mediators of acute inflammation

Kinin system
Clotting pathway
Thrombolytic pathway
Complement pathway

13

Outcomes of acute inflammation

Minimal tissue damage = resolution

Some tissue damage =Fibrosis

Marked neutrophil reaction with tissue damage = Suppuration- abscess

Damaging agent persists = Chronic inflammation