Inflammation Flashcards
What are the causes of acute inflammation?
Microbial infections
Hypersensitivity reactions
Physical and chemical agents
How do you recognise acute inflammation?
Red- dilation of blood vessels
Hot- increased blood flow
Swollen- mainly due to oedema
Painful- stimulation of nerve endings by pressure and chemical mediators
Loss of function
What are the two initial reaction phase of acute inflammation?
Vascular and exudative phase
What happens in the vascular phase?
Dilation and increased permeability
What happens in the exudative phase?
Fluid and cells escape from permeable venules
What is the characteristic cell of acute inflammation?
Neutrophil polymorph
What happens to capillary sphincters during inflammation?
They relax allowing a greater blood flow into the capiilaries
What happens to the plasma proteins in inflammation?
Net flow out of the blood
What are the features of the exudate phase?
High protein content (immunoglobins,)
Fibrinogen- fibrin (acutely inflamed organ surfaces covered by fibrin)
High turnover, continuously removed via lymphatics
What is transudate in respect to the exudate phase?
The normal state the body is in.
No net flow out, normal vascular permeability, low protein content
What is increased vascular permeability?
Produced by chemical mediators (histamine, bradykinin)
Involves stimulation of endothelial cell
Only in post capillary venules
Through transient, intercellular gaps
What happens to the lymphatic system in acute inflammation?
Lymphatics dilate, drain fluid from exudate, antigens carried to lymph nodes- recognised by lymphocytes
What are the functions of neutrophils?
Kills organisms, degrade necrotic tissue, ingest offending agents, produce chemical mediators, produce toxic oxygen radicals, produce tissue damaging enzymes
What is transmigration?
Cells adhere to the vessel walls, squeeze through the endothelial walls into the tissue
What is chemotaxis?
The process neutrophils use to find antigens. The receptors are filled as the neutrophil moves along the concentration gradient
What are the 4 enzymatic cascade systems that plasma contain?
Complement system, the kinins, the coagulation factors, fibrinolytic system
How do neutrophils do their function?
Movement, recognition of and adhesion to micro-organisms, phagocytosis, intracellular killing of micro-organisms
Why are neutrophils filled with pre-made granules?
So toxic agents can be released in minutes
What is phagocytosis?
The cell taking thing inside to destroy them
What is opsoniation?
Opsonins coating receptors on leucocytes and greatly enhancing phagocytosis
Some examples of major opsonins?
Fc fragment of IgG
C3b
Collectins- plasma proteins that bind to micrbial cell walls
Examples of acute inflammation
Serous- protein rich fluid exudate
Catarrhal- mucus hypersecretion
Fibrinous-exudate contains plentiful fibrin
Haemorrhagic- severe vascular injury
Explain the suppuration type of inflammation
Formation of pus-neutrophils, bacteria, cellular debris
Nearly always caused by an infective agent
What is in abscess?
A collection of pus surrounded by a membrane of sprouting capillaries, neutrophils and fibroplasts
Where may deep seated abscesses drain?
Along a sinus tract or fistula
Describe ulceration as a form of inflammation
A local defect or excavation which has been produced by the sloughing of inflammatory necrotic tissue
What are the beneficial effects of acute inflammation?
Dilution of toxins
Entry of antibodies
Fibrin formation
Transport of drugs
Delivery of nutrients and oxygen
Stimulation of the immune response
What are the harmful effects of acute inflammation?
Digestion of normal tissues
Swelling
Inappropriate inflammatory response
What is type 1 hypersensitivity?
The classic allergic response. Mast cells release large amounts of histamines through degranulation
What is pyrexia?
An increase of temperature due acute inflammation
What are some constitutional symptoms of acute inflammation?
Malaise, anorexia and nausea
What are the haematological changes of acute inflammation?
Increased erythrocyte sedimentation rate
Anaemia
Leukocytosis
What is fibrosis?
The thickening and scarring of connective tissue
What factors favour resolution?
Minimal cell death and tissue damage
Regenerative tissue
Rapid destruction of the agent
Rapid removal of fluid and debris by vascular drainage
What is the end result of organisation?
Replacement of destroyed tissue by granulation tissue
What factors favour organisation?
Large amounts of fibrin
Substantial necrosis
Exudate and debris cannot be removed
What is a classic example of granulation tissue?
Capillary loops and macrophages
In granulating tissue what is the inflammatory exudate replaced by?
Capillaries, macrophages, fibroblasts and collagen
What is granulation tissue regulated by?
Growth factors, TNF, EGF, FGF
What is TB and Leprosy and example of?
Primary chronic inflammation caused by resistence of infective agent to phagocytosis and intracelullar killing
What is chronic tophaceous gout with crippling gouty arthritis an example of?
Primary chronic inflammation caused by foreign body reactions to endogenous materials
What is asbestos an example of?
Primary chronic inflammation caused by foreign body reactions to exogenous materials
What rheumatoid arthritis an example of?
Primary chronic inflammation caused by an autoimmune disease
What is ulcerative colits an example of?
Primary chronic inflammation caused by specific diseases of unknown aetiology
What is sarcoidosis an example of?
Primary chronic inflammation caused by granulomatous
What factors favour progression from acute to chronic inflammation?
Indigestible substances
Deep seated suppurative inflammation where drainage is delayed or inadequate
Recurrent episodes of acute inflammation and healing
What is osteomyelitis?
A chronic abcess which is extremely difficult to eradicate
What is chronic cholecystitis?
Replacement of wall by fibrous tissue , lymphocytes rather than neutrophils predominate
What does chronic inflammation look like?
Chronic ulcers, chronic abscesses, thickening of the wall of a hollow viscus, granulomatous inflammation, fibrosis
How do you identify a chronic ulcer?
Mucosa breached, base lined by granulation tissue and punched through other tissue layers
What cells are more common in chronic inflammation?
Lymphocytes, plasma cells, macrophages, multinucleate giant cells
What are macrophages?
Phagocytic capabilites
Can harbour viable organisms resistant to lysosmal enzymes
Produce a range cytokines
What is a granuloma?
An aggregate of epitheloid macrophages
What is a histiocyte?
Macrophage in connective tissue
What causes granulomatous disease?
Specific infections, foreign bodies, specific chemicals, drugs
Exudate vs transudate?
High protein content from increased vasc perm vs low protein from normal vasc perm
Acute vs chronic inflammation
Distinguished by dynamics and character process
What is granulation?
Important healing process with small blood vessels and connective tissue
What is fibrin?
Deposited in acute inflammation
What is “fibrous”?
Typical scar tissue with collagen
