CTB8 - Anaphylaxis: Cardiorespiratory Problem

Question 1

Briefly describe anaphylaxis.

Answer 1

Severe allergic reaction brought on by various allergens.

Question 2

What are the four signs of acute inflammation?

Answer 2

Rubor - redness.
Calor - heat.
Tumour - swelling.
Dolor - unpleasant sensation

Question 3

Are deaths common for anaphylaxis?

Answer 3

May have life threatening implications but these are relatively rare on account of prompt treatment

Question 4

What is the fifth additional sign of acute inflammation?

Answer 4

Functio laesa- loss of function

Question 5

Give identifiable features of anaphylactic episodes

Answer 5

Rapid onset.
Generalised skin itching - pruritis
Tingling sensation in extremities. 
Skin reddening - erythema
Swelling - urticaria and angioedema.
Itchy runny nose - rhinitis
Itchy runny eyes - conjunctivitis
Nausea, abdominal pain, vomiting
Breathing difficulties due to laryngeal oedema and bronchoconstriction
Hypotension - dizzy, faint

Question 6

Define allergens vs antigen.

Answer 6

Antigen is any foreign particle able to stimulate an immune response. Allergens are similar but commonly induce a more severe allergic reaction, as opposed to an immune response solely.

Question 7

What are the three most common allergens for anaphylaxis?

Answer 7

Food. Poisons/toxins. Medications.

Question 8

Give an example for an allergen that is more of a risk in younger children and older patients.

Answer 8

Young - food.

Older - medicinal products.

Question 9

Define innocuous.

Answer 9

Substances that are innocuous generally have no immune response associated with them, unless the person is specifically allergic to them.

Question 10

Give examples of common drugs, foods, and other allergens that can stimulate an immune response in the case of anaphylaxis.

Answer 10

Drugs - NSAIDs, x ray contract mediums. Anaesthetics, antibiotics.
Food - nuts, milk, egg, fish, shellfish.
Insect stings - bees, hornets, wasps.
Chemicals - latex, hair dye.

Question 11

Define hypersensitivity and hypersensitive reactions.

Answer 11

Unwanted responses produced by the immune response in response to otherwise innocuous allergens. Can be classified at type I, II, III and IV (not based on severity)

Question 12

Briefly describe each type of hypersensitivity reaction.

Answer 12

Type I - immediate reaction using IgE antibodies e.g. anaphylaxis.
Type II - cytotoxic reaction involving IgM and IgG antibodies e.g. autoimmunity and haemolytic anaemia.
Type III - complement fixation involving IgG antibodies e.g. inflammation.
Type IV - delayed sensitive T cell response e.g. inflammation.

Question 13

What type of hypersensitivity reaction does anaphylaxis fall under?

Answer 13

Type I hypersensitivity

Question 14

Describe a brief overview of the production of antibodies during a normal immune response and a type I hypersensitive reaction.

Answer 14

Normal - foreign antigen detected. Bind to IgM antibodies on lymphocytes. Proliferation occurs which secrets IgM antibody clones. Class is switched to IgG during immune response. 
Hypersensitivity - foreign antigen detected. Bind to IgM antibodies on lymphocytes. Proliferation occurs however the antibody class switches to IgE by the T helper cells. Long term IgE production which interact with inflammatory white blood cells.

Question 15

Give two types of inflammatory white blood cells involved in hypersensitivity reactions. Give two common locations for these.

Answer 15

Mast cells. Basophils.

Mast cells are found in connective tissue and epithelial mucous.

Question 16

Are mast cells and basophils the same? Give brief introduction to their similarities and differences (if any)

Answer 16

Similarities - structure and fcuntion are similar.

Differences - from different cell lineages; basophils are myeloid whereas mast cells are lymphoid

Question 17

What are the two types of mediators within the granules of the mast cells/basophils?

Answer 17

Inflammatory mediates - e.g. histamines.

Arachidonic acid metabolites e.g. prostaglandins

Question 18

Discuss the process by which mast cells/basophils become activated.

Answer 18

FceRI receptors present on mast cell/basophils surface which are high affinity IgE receptors. Initial exposure causes release of IgE antibodies. Antibody binds to receptor. Until two adjacent antibodies are bound to two adjacent FceRI receptors, no anaphylaxis occurs. Upon adjacent binding, mast cell/basophils becomes activated. Intracellular signalling transduction pathway is activated which causes release of i granules (which contain histamine) or stimulates synthesis of other inflammatory mediators.

Question 19

Give four different inflammatory mediators whose synthesis is stimulated upon activation of the mast cell/basophils.

Answer 19

Cysteinyl leukotrienes
Prostaglandins
Platelet activating factors
Cytokines

Question 20

How many histamine receptors are there? Do they each have the same effect? Give one example of same/different effect.

Answer 20

Four receptors: H1-H4. Some effects occur at multiple receptors however some effects are unique to each receptor.

E.g. receptor H1 involved in itching effects whereas receptor H4 involved in immune modulation

Question 21

Give two examples of arachdonic acid metabolite inflammatory mediators.

Answer 21

Prostaglandins and cysteinyl leukotrienes

Question 22

Which inflammatory mediators is associated with the greatest number of anaphylaxis symptoms?

Answer 22

Histamine

Question 23

What is plasma exudation? Give a brief overview of the process.

Answer 23

Plasma exudation refers to the leaking of plasma through endothelial cells, resulting in swelling. Occurs as endothelial cells undergo contraction which increases the gaps between the cells. This, alongside vasodilation, causes a large amount of plasma to be released from the bloodstream.

Question 24

What does the ABC of treating anaphylaxis refer to?

Answer 24

Airway
Breathing
Circulation

Question 25

Describe how anaphylaxis may cause breathing difficulties.

Answer 25

Bronchoconstriction may occur, narrowing the airway. In addition, plasma exudation near the airways (e.g. laryngeal oedema) can further reduced airway lumen size.

Question 26

Describe how anaphylaxis may cause hypotension.

Answer 26

Plasma exudation causes excess fluid loss from blood volume. Vasodilation occurs which increases blood flow to surface vessels which may contribute to low blood pressure generally.

Question 27

Describe how anaphylaxis may cause intestinal pain.

Answer 27

Contraction of smooth muscle within the intestines, can cause stomach pain.

Question 28

What are the two main effects that adrenaline has for treating anaphylaxis?

Answer 28

Reversing bronchoconstriction.

Elevation of blood pressure.

Question 29

What effects does adrenaline have on airway and breathing and how?

Answer 29

Clears airway and eases any breathing difficulties by inhibition of plasma exudation (reduces laryngeal oedema) and induce bronchodilation (reverse bronchoconstriction).

Question 30

Describe the effects that adrenaline has on circulation - specifically on the heart.

Answer 30

Increased heart rate and contractility, allowing for increased blood pressure elevation.

Question 31

Describe the effects that adrenaline has on circulation - specifically on vasculature .

Answer 31

Increases peripheral vasoconstriction, reversing vasodilation, helping to elevate blood pressure.

Question 32

Describe the effects that adrenaline has on circulation - specifically via the kidney.

Answer 32

Stimulation of renin angiotensin system which increases blood pressure via increased sodium retention - increased water retention, increased circulating blood volume, increased blood pressure.