3. Acute Inflammation Flashcards
Define acute inflammation
The initial protective tissue response to injury or destruction of tissues, which serves to destroy, dilute, or wall off both the injurious agent and the injured tissues.
List the five clinical features of acute inflammation
Redness Heat Swelling Pain Loss of function
What is inflammation?
The normal response of living tissues to cellular injury
What is the purpose of inflammation?
To localise the causative agent, limit tissue injury and restore tissue to normality
What are the beneficial effects of inflammation?
Dilution of toxins Entry of antibodies Fibrin formation and isolation of micro-organisms Delivery of nutrients and oxygen Stimulation of immune system
What are the harmful effects of inflammation?
Digestion of normal tissue
Swelling
Loss of normal function
Inappropriate or excessive inflammatory response
What are three main elements of acute inflammation?
Changes in small blood vessels
Recruitment of neutrophils
Increased levels of chemical mediators
What are examples of causes of acute inflammation?
Microbial infections Physical agents Chemicals Tissue necrosis of any causes Foreign bodies
What are the changes of in the microcirculation of acute inflammation?
Changes in vascular calibre and hence blood flow is an early event
Changes in vascular permeability is also early
Combined these processes contribute to the formation of a FLUID EXUDATE
causing the clinical observation of swelling
What is the key cell in inflammation?
Neutrophil
What are the features of neutrophils?
Bone marrow produced Normally present in blood Short lived Specialised for defense roles Phagocytic Capable of killing micro-organisms
What do the neutrophils do?
Movement Adhesion to micro-organisms Phagocytosis Intracellular killing Lysosomal enzyme release
What are the 7 stages of phagocytosis?
Chemotaixis and adherence of microbe to phagocyte
Ingestion of microbe by phagocyte
Formation of phagosome
Fusion of the phagosome with a lysosome to form a phagolysosome
Digestion of ingested microbe by enzymes
Formation of residual body containing indigestible material
Discharge of waste material
What chemotaxis?
Chemotaxis is the ability of cells such as neutrophils to move along a concentration gradient towards some chemical substance
What are examples of chemotactic substances?
inflammatory mediators,
cytokines,
complement components,
neutrophil degradation products.
What does NSAIDs do?
Reduce the poduction of prostaglandins
What corticosteroids?
Suppress prostaglandins, cytokines and nitric oxide
What do cytokine modulators do?
TNF inhibitors
What are the four possible outcomes of acute inflammation?
- Resolution Complete restoration of the tissue to normal
- Suppuration – chronic suppurative inflammation
- Repair with organisation and progressive fibrosis
- Progression to chronic inflammation
What is chronic suppurative inflammation?
The persistent accumulation of pus?
What is pus?
A mixture of living, dead and dying neutrophils, cellular debris and inflammatory exudate
What is an abscess?
A collection of pus within a newly formed cavity within tissues
What is an empyema?
A collection of pus within a naturally existing anatomical cavity
What is a lung abscess?
Severe localised pus-filled newly formed cavity that develops inside the tissue of the lungs
What are the systematic effects of inflammation?
Weight loss
Pyrexia
General, non-specific symptoms
Why do we feel run down etc?
Due to inflammation which leads to changes in the basal ganaglia due to circulating systems
