Flashcards in 4. Acute inflammation Deck (54):
1
What are the causes of acute inflammation?
- tissue death (ischaemia, trauma, toxins, chemical insults, thermal injury, radiation)
- infection (especially bacterial, pyogenic)
2
Define pyogenic
Pus forming
3
Define suppuration
The formation of pus
4
What is pus?
An accumulation of acute inflammatory cells, dead cells, bacteria etc.
5
What comes after acute inflammation?
Either
- healing by regeneration
- healing by repair
or
- chronic inflammation
6
When does healing by regeneration occur?
After acute inflammation, when the cells can regrow
7
When does healing by repair occur?
After acute inflammation, when the cells canon regrow
8
When does chronic inflammation occur following acute inflammation?
After acute inflammation, when the damaging agent persists
9
What are the purposes of acute inflammation?
- clear away dead tissues
- locally protect from infection
- allow access of immune system components
10
What are the 4 cardinal signs of inflammation?
- calor (=heat)
- rubor (=redness)
- dolor (=pain)
- tumor (=swelling)
11
In addition to the main 4 cardinal signs of inflammation, what is the extra one?
Disturbance of function
12
Why does rubor (redness) and calor (heat) occur in inflammation?
Due to vascular dilation
13
Why does swelling occur in inflammation?
Due to inflammatory exudate into surrounding tissues
14
Acute inflammation will look different in different organs. Name 4 different types of acute inflammation.
- serous
- fibrinous
- purulent
- pseudomembranous
15
What occurs in serous inflammation?
Fluid accumulates in cavity
16
What occurs in fibrinous inflammation?
Precipitation of fibrin
17
What occurs in purulent inflammation?
Formation of pus
This is very common
18
What are 3 components of the acute inflammatory reaction?
1. vascular reaction
2. exudative reaction
3. cellular reaction
19
What is the vascular reaction? (a stage of acute inflammatory response)
Dilatation of blood vessels (=rubor), changes in flow
20
What is the exudative reaction? (a stage of acute inflammatory response)
Vessels become leaky, formation of inflammatory exudate (=tumor)
21
What is the cellular reaction? (a stage of acute inflammatory response)
Migration of inflammatory cells out of vessels
22
Define pyrexia
High temperature due to inflammation
23
How can the severity of acute inflammatory response in a patient be quantified?
- pyrexia
- acute phase reaction
24
Give an example of a protein that is measured in acute phase reaction?
C-reactive protein
ESR (erythrocyte sedimentation rate)
25
What is the acute phase reaction?
Systemic and metabolic changes that occur within hours of an inflammatory stimulus. - acute phase proteins.
26
Describe the vascular reaction?
Microvascular dilation causes an increase in flow and then flow eventually deceases as the vessels become leaky
27
What causes increased permeability of vessels?
Mediated =
histamine
bradykinin
NO
leukotriene B4
complement components
Non-mediated =
direct damage to endothelium eg. toxins, physical agents
28
How can we interfere with increased vascular permeability?
Drugs can affect the mediators which cause mediated increased permeability
29
What happens in a capillary if there is a greater hydrostatic pressure?
Fluid is pushed out of the capillaries
30
What happens in a capillary if there is a greater oncotic pressure?
Fluid will enter the capillaries
31
At the arterial end of a capillary, is hydrostatic or oncotic pressure higher?
Hydrostatic pressure > oncotic pressure at the ARTERIAL end
32
What does acute inflammatory exudate consist of?
Protein rich (50g/l)
- immunoglobins
- fibrinogen
33
What are the benefits of acute inflammatory exudate?
constantly turning over
- dilution of noxious agents
- transport to lymph nodes
- supply of nutrients, O2
- spread of drugs
- spread of antibodies
- spread of inflammatory mediators
34
What is pericarditis?
Inflammation of the pericardium of the heart
35
What do you see in pericarditis?
A friable shaggy covering of the heart rather than being smooth and shiny.
This is due to fibrinous inflammation (the shaggy material is precipitated fibrin from the inflammatory exudate)
36
What happens during the cellular reaction?
- accumulation of neutrophils in the extracellular space (neutrophils are normally present in the blood but migrate into the extracellular space in infection)
- in severe cases, accumulation of neutrophils, cellular debris and bacteria forms pus
37
What do you see in acute meningitis caused by a pyogenic bacterial infection?
Rather than being clear and shiny, the arachnoid covering over the cerebellum is cloudy because of the cell rich exudate in the subarachnoid space (pus)
38
What type of cells are in the subarachnoid space in acute bacterial meningitis?
Neutrophil polymorphs, these are characteristic of acute inflammation
39
How would the alveoli feel in the case of bronchopneumonia?
It would feel solid compared to the surrounding lung as the alveoli are filled with the acute inflammatory exudate rather than air
40
What are the main characteristics of neutrophils?
- produced in the bone marrow
- commonest white cell in the blood
- increase in acute inflammation
- motile, amoeboid, can move into tissues
- directional chemotaxis
- short lifespan (hours in tissues)
- phagocytic, microbiocidal
41
Where are neutrophils produced?
In the bone marrow
42
What is the most common white cell in the blood?
Neutrophils
43
Do neutrophils have a long or short lifespan?
Short.
(hours in tissues)
44
What are the stages as neutrophils flow in the blood during inflammatory response?
1. margination
2. rolling - adhesion (pavementing - can see this microscopically)
3. migration (RBC diapedesis)
4. chemotaxis
45
Where are the mediators of acute inflammation derived?
Cell derived or plasma derived
46
List the plasma derived mediators of acute inflammation
- kinin system
- clotting pathway
- thrombolytic pathway
- complement pathway
47
What are the cell derived mediators of acute inflammation?
Stored = histamine
Synthesised =
prostaglandins
leukotrienes
PAF
cytokines (IL1, IL8, TNFa)
NO
chemokines
48
Why are the mediators of acute inflammation important to know about?
We can interfere with them with drugs
49
What contributes to laboratory assessment of inflammation?
- full blood count
- erythrocyte sedimentation rate
- acute phase reaction eg. C-reactive protein
50
What diseases are caused by the inflammatory pathway going wrong?
- systemic inflammatory response syndrome
- acute (adult) respiratory distress syndrome
- chronic granulomatous disease of childhood
- hereditary angio-oedema
- amyloidosis
51
What is resolution?
After acute inflammation when there is minimal tissue damage
52
What is fibrosis?
After acute inflammation when these is some tissue damage
53
What happens after acute inflammation when there is marked neutrophil reaction with tissue damage?
Suppuration - abscess
54