Clinical Lab sciences : Acute Inflammation
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Transcript of Clinical Lab sciences : Acute Inflammation
Acute InflammationAcute Inflammation
Faculty of Medicine & Health Sciences
ObjectivesObjectives Describe the range of situations in which an acute
inflammatory reaction can occur List the main steps in the acute inflammatory response Describe the composition of an acute inflammatory
exudate and some of its clinical effects Describe the functions of the components of the acute
inflammatory exudate Describe most likely consequences of acute inflammatory
reaction & its role as starting point for recovery & repair
DefinitionDefinition
What is the acute inflammatory response?
Answer: It is the most common response of the body tissues to an area of nearby damage
What sort of things stimulate What sort of things stimulate the acute inflammatory the acute inflammatory
response?response?
microorganisms (esp bacterial) trauma (eg surgical incision) ischaemic necrosis (“infarction”) radiation damage (eg sunburn) chemical damage (eg acids, alkalis)
What is the purpose of the What is the purpose of the acute inflammatory reaction ?acute inflammatory reaction ?
to destroy or neutralise the damaging agent
to liquefy and remove dead tissue to prepare the damaged area for
healing
How does it do this?How does it do this? by the production of an acute inflammatory
exudate derived from blood components from capillaries adjacent to the damaged areas
the acute inflammatory exudate comprises: fluid fibrin neutrophils, but also a few macrophages and
lymphocytes
How does the exudate work?How does the exudate work?
fluid dilutes any toxins fluid carries nutrients, mediators,
antibodies fibrin - function is speculative NEUTROPHILS - actively phagocytic
of living tissue (eg bacteria), but also necrotic debris
What are the stages in What are the stages in exudate formation ?exudate formation ?
STEP 1 Blood vessels near to damaged tissue
become dilated Blood flow initially increases, then slows
down Axial flow pattern of blood is lost
WHY DOES THIS HAPPEN ?
Vessels dilateVessels dilate
substances released by dead tissue act on blood vessels
Endothelial cells swell & Endothelial cells swell & retract; vessels leak.retract; vessels leak.
water, salts and protein leak out into damaged area an important protein is fibrinogen
Neutrophils marginate & Neutrophils marginate & emigrateemigrate
neutrophils stick to endothelial cells neutrophils migrate through capillary into damaged area.
NEUTROPHIL MARGINATION NEUTROPHIL MARGINATION
HISTOLOGY of margination of neutrophils in a capillary
EXUDATION EXUDATION ….….
HISTOLOGY- fluid, proteins and neutrophils move into area of damage
CLINICAL TYPES OF CLINICAL TYPES OF EXUDATEEXUDATE
SEROUS PURULENT FIBRINOUS FIBRINO-PURULENT
A SEROUS EXUDATEA SEROUS EXUDATE
there is excess fluid accumulation,; here it is in pericardial sac
A PURULENT EXUDATEA PURULENT EXUDATE
a purulent exudate in the meninges
HISTOLOGY OF PURULENT HISTOLOGY OF PURULENT EXUDATEEXUDATE
note the live and dead neutrophils
A FIBRINOUS EXUDATEA FIBRINOUS EXUDATE
note the shaggy exudate on the surface of the pericardium
HISTOLOGY OF FIBRINOUS HISTOLOGY OF FIBRINOUS EXUDATEEXUDATE
note the masses of pink-staining fibrin
Mediators of inflammationMediators of inflammation
Vascular changes Cellular Changes Mediated by a series of mediators of acute
inflammation MUST be studied from a textbook. This knowledge is the basis of understanding the
treatment of inflammatory conditions WILL be examined
•Cell-derived factors•Plasma derived factors•PRIVATE STUDY
WHO WAS CELSUS, AND WHO WAS CELSUS, AND WHO CARES ?WHO CARES ?
his cardinal signs calor dolor rubor tumor
Acute inflammation:clinicalAcute inflammation:clinical Malaise, fever, pain, rapid pulse Neutrophil leukocytosis Elevated ESR Increased acute phase proteins
IL-1 induced e.g. CRP
Acute inflammation:summaryAcute inflammation:summary the most common early tissue response to
tissue damage exudate is derived from local vessels vascular flow and permeability altered neutrophils are the main effector cells activation of endothelium is a key process chemical mediators attract neutrophils into
tissues
Acute inflammation:summaryAcute inflammation:summary Neutrophils kill microorganisms and break
down damaged tissue Neutrophils are short-lived cells Macrophages play a small role The exudate can vary in composition
Purulent, fibrinous, serous
Private StudyPrivate Study
Endothelial activation factors mediating vessel changes neutrophil margination & emigration Phagocytosis mediators of acute inflammation in general