Acute inflammation

Question 1

what are the main causes (aetiologies) of acute inflammation?

Answer 1

micro-organisms
injury/ trauma to tissue
chemical
extreme conditions
dead tissue
hypersensitivity

Question 2

microorganisms and acute inflammation

Answer 2

e.g bacteria, fungi, viruses, parasites- Pathogenic organisms that cause infection

Question 3

Recognise the benefits of acute inflammation

Answer 3

rapid response to injury site
cardinal signs (redness, swelling, pain and heat) and loss of function
neutrophils move from blood vessels to E.C space -destroy organisms and denature antigen for macrophages- can eradicate the infection
plasma proteins localise the process
resolution and return to normal

Question 4

what are the cardinal signs of inflammation? ie simple sign of symptoms

Answer 4

Rubor (redness)
Calor (heat)
Tumor (swelling)
dolor (pain)
loss of function

Question 5

Injury/trauma to tissue and acute inflammation

Answer 5

All injuries, even sterile (e.g surgery) cause acute inflammation
‘mechanical’= a blow, crush, cut, or penetrating wound

Question 6

Chemical cause for acute inflammation

Answer 6

upset stable environment (e.g acid or alkali, bile (alkaline) and urine cause irritation when in inappropriate place)

Question 7

Extreme conditions (physical) cause for acute inflammation

Answer 7

e.g sunburn from heat, frostbite from cold, ionising radiation

Question 8

Hypersensitivity for acute inflammation

Answer 8

several classes of reaction

Question 9

dead tissue cause of acute inflammation

Answer 9

in tissue that dies, cell necrosis irritates adjacent tissue

Question 10

what microvascular changes occur because of acute inflammation?

Answer 10

• change in vessel radius/ flow
• change in vessel permeability as blood vessels dilate and more gaps arise for things to infiltrate it.
• movement of neutrophils from the vessel to the extra-cellular ‘space’ compartment

Question 11

increased blood flow?

Answer 11

blood vessels dilate which increases the blood flow to the site of inflammation. RESULT= observed redness and heat

Question 12

Increased permeability?

Answer 12

an increase in permeability of the capillaries allows fluid and plasma proteins to move into the interstitial spaces. This process is called EXUDATION. What is leakes is called exudate. Exudation causes the formation of an oedema (accumulation of fluid in the extra-vascular space).
This explains the swelling of tissue in acute inflammation. Swelling causes pain and reduces function.

Question 13

Define exudation?

Answer 13

process by which there is an increase in permeability of the capillaries, allowing fluid and plasma proteins to move into the interstitial spaces

Question 14

Exudate?

Answer 14

a mass of cells and fluid rich in protein that has seeped out of blood vessels. It contains immunoglobulin and fibrinogen.

Question 15

Migration of neutrophils

Answer 15

1. margination- the neutrophils (WBCs) move to endothelial aspect of lumen (lining)
2. pavementing/adhesion- neutrophils adhere (stick) to endothelium
3. emigration- neutrophils squeeze between endothelial cells to extravascular tissues- guided to site of infection

Question 16

describe sequence of events in exudate formation

Answer 16

An increase in permeability of capillaries during acute inflammation allows exudate to leak into extravascular space. It explains the swelling of tissue in acute inflammation. Can lead to oedema, which is the accumulation of fluid in the extravascular space. This swelling causes pain, due to pain receptors being stretched, and loss of function.

Question 17

What are the local effects of acute inflammation?

Answer 17

1. Transient (lasting only a short time) arteriolar constriction. Lasts a few moments, probably protective
2. local arteriolar dilation. Relaxation of smooth muscle of vessel.

Question 18

List the systemic effects of acute inflammation

Answer 18

1. pyrexia- raised temperature
2. feel unwell (malaise) anorexia, nausea, abdominal pain and vomiting in children
3. neutrophilia- raised white cell count, produced and released by bone marrow
4. septic shock

Question 19

Outcomes of acute inflammation

Answer 19

suppuration (pus formation)
abscess
organisation
dissemination
chronic inflammation

Question 20

suppuration

Answer 20

sup backwards = pus
pus formation, made up of dead tissue, organisms, exudate, neutrophils, fibrin, red cell and debris. ‘membrane’ surrounds pus to keep it contained locally. May extend into other tissues (still contained) and progress inflammation further
many neutrophils die at the site of their action so form the pus that is found at infection site

Question 21

abscess

Answer 21

a collection of pus (suppuration) under pressure. Can be a single locule, or multiloculated (when pus bursts through the pyogenic membrane and forms new cavities)

Question 22

dissemination

Answer 22

spread to the bloodstream, and the patient becomes ‘septic’
bacteraemia= bacteria in the blood
septicaemia= growth of bacteria in blood
toxaemia= toxic products in blood

Question 23

inflammation leads to the following stages

Answer 23

granulation tissue- occurs after a large amount of damage, or an ability to remove dirt from wound-
capillaries grow into the inflammatory mass. Means plasma proteins, macrophages and fibroclasts which lay down collagen to repair damage have access
-healing and repair
-scar formation

Question 24

how can process of acute inflammation be detrimental to patient

Answer 24

• release of lysosomal enzymes by inflammatory cells may have harmful effects
• digestion of normal tissue
• swelling
• inappropriate inflammatory response

Question 25

digestion of normal tissue effect on patient

Answer 25

enzymes such as collagenases and proteases may digest normal tissues, resulting in their destruction. This may result particularly in vascular damage e.g type III hypersensitivity

Question 26

Swelling:- effect on patient

Answer 26

Swelling of acutely inflamed tissues may be harmful. Inflammatory swelling is especially serious when it occurs in an enclosed space such as the cranial cavity. Thus, acute meningitis or a cerebral abscess may raise intacranial pressure to the point where blood flow into the brain is impaired.

Question 27

Inappropriate inflammatory response:- effect on patient

Answer 27

Sometimes acute inflammatory responses appear inappropriate, such as those which occur in type I hypersensitivity reactions (e.g hay fever) where the provoking environmental antigen (e.g pollen) otherwise poses no threat to the individual. Such allergic inflammatory responses may be life- threatening, for example extrinsic asthma.

Question 28

mediators of vasodilation and vasoconstriction

Answer 28

histamine causes vasodilation while serotonin causes vasoconstriction. These two molecules contradict each other in terms of vasodilation and vasoconstriction and so balance each other out through homeostasis

Question 29

mediators of altered permeability

Answer 29

prostaglandins and leukotrienes produce molecules that aid and prevent increased permeability, and so balance each other out

Question 30

mediators of neutrophil adhesion

Answer 30

molecules can either aid or inhibit the process of neutrophil adhesion

Question 31

what effect do mediators have?

Answer 31

mediators can have positive and negative effects, and result in a dynamic balance. They can favour or inhibit acute inflammation relative to need.

Question 32

Is inflammation a quick response?

Answer 32

Yes

Question 33

Oedema

Answer 33

accumulation of fluid in the extravascular space- swelling

Question 34

What flow is there in a normal vessel?

Answer 34

laminar flow | velocity of the fluid through vessel is constant at any point in the fluid

Question 35

Margination

Answer 35

movement of neutrophils from centre of vessel to the vessel wall

Question 36

Diapedesis

Answer 36

movement of white blood cells out of through capillary walls

Question 37

Inflammation terminology

Answer 37

(add -itis usually) meninges- meningitis appendix- appendicitis others:- pneumonia pleural cavity

Question 38

effector mechanism of inflammation- cell?

Answer 38

neutrophil

Question 39

neutrophils

Answer 39

- can recognise foreign antigens | they move towards the antigen by chemotaxis

Question 40

When do neutrophils die?

Answer 40

when granule contents are released they produce pus although it's contained, it might extend into other tissues- progressing inflammation

Question 41

fibrinogen

Answer 41

helps blood to coagulate in vessels and clot exudate outwith vessels performs like a plug localises inflammatory process- stops spreading

Question 42

chemotaxis

Answer 42

movement of neutrophils in response to inflammation Move up a conc. gradient to where the messenger is coming from- requires energy

Question 43

mediators of acute inflammation

Answer 43

``` vasodilation and vasoconstriction altered permeability neutrophil adhesion chemotaxis itch and pain ```

Question 44

What can septicemia cause/lead to?

Answer 44

septic shock- tachycardia, peripheral vasodilation, hypotension (low bp) shock is the inability to perfuse tissues

Question 45

what effects can mediators have on acute inflammation

Answer 45

they can promote/ inhibit inflammatory response

Question 46

Summary of outcomes of acute inflammation

Answer 46

``` resolution suppuration organisation dissemination chronic inflammation ```

Question 47

Histamine

Answer 47

it's a neurotransmitter. it's in form of granules that are released from inside mast cells IgE and antigen reaction changes mast cell membrane the histamine binds to H1 receptors and causes vasodilation, increased permeability

Question 48

Anti-histamines

Answer 48

work by blocking/inhibiting H1 receptors (histamine receptors)

Question 49

pyrexia

Answer 49

raised temperature

Question 50

Abscess

Answer 50

collection of pus under pressure single locule, multiloculated can release discharge collapses- healing and repair depending on size small may drain naturally, or simply shrink, dry up and disappear Large- may need antibiotics to clear the infection + pus may need to be drained.

Question 51

multiloculated abscess

Answer 51

pus bursts through pyogenic membrane and forms new cavities

Question 52

Pyaemia

Answer 52

discharge to bloodstream

Question 53

what is normal laminar flow like?

Answer 53

white blood cells in the middle surrounded by red blood cells

Question 54

flow in inflammation

Answer 54

neutrophils found near endothelium so capillary walls (margination) RBCs aggregate in centre of lumen (rouleaux)

Question 55

what do neutrophils do in terms of granule release?

Answer 55

their granules possess oxidants eg H2O2 and enzymes eg proteases they release the granule contents phagocytose/destroy foreign antigens when neutrophils release their contents they die and produce pus