YR 2 F1- Anaphylaxis

Question 1

How does anaphylaxis differ from allergy?

Answer 1

A major difference between anaphylaxis and other allergic reactions is that anaphylaxis typically involves more than one system of the body which leads to shock ( decreased tissue perfusion and oxygenation of tissues).

Question 2

Which type of hyerpsensitivity is anaphylaxis?

Answer 2

Type 1 hypersensitivity

Question 3

How many types of hypersensitivity are there?

Answer 3

Type 1 - antibody mediated

Type 2 - antibody mediated

Type 3 - antibody mediated

Type 4 - T cell mediated

Question 4

What do you call an foreign antigen that is actually not harmful to the body?

Answer 4

Allergen

Question 5

What is the mechanism of the development of anaphylaxis?

Answer 5

Antigen is detected but this antigen is not an actually harmful, so this is called allergen. The allergen mediates an immune response. Tcells activate b cells to produces IgEs. IgE attaches onto the FcR receptors on MAST CELLS which then release cytokines and cause more WBC to be activated like basophils. Once activated degranulation happens of the WBCs and releases histamine.

Question 6

Role of histamine in anaphylaxis

Answer 6

vasodilator - dcreases bp

bronchoconstrictor - increase rr

increases the vascular permeability - causes sweeling/inflammation

Question 7

What drug do you give to conteract histamine for anaphylaxis?

Answer 7

Adrenaline

Question 8

During anaphylaxis do you inject it intermuscularly or subcutaneously

(in tissues)

WHy?

Answer 8

Intermuscularly because provides rapid relief of hypersensitivity (exaggerated immune response to an antigen) reaction

Question 9

Adrenaline is a vasoconstrictor and bronchodilator

Which receptors do adrenaline bind to?

Answer 9

Alpha 1

Beta 2

Question 10

What foods or substances are capable of inducing anaphylaxis?

Answer 10

tree nuts, milk, egg, sesame seeds, fish, and shellfish

venom/ insect stings

medication

latex

Question 11

What is the significance of the mast cell tryptase test in anaphylaxis?

Answer 11

Tryptase (enzyme) is releases by mast cells.

Serum Tryptase is a marker of mast cell degranulation

SO the more tryptase is found the higher the amount of activated mast cells.

Question 12

The mast cell tryptase test is done at the start of admitting and then 2 hours later. Why is that?

Answer 12

Mast cell is done again at 2 hours because it is at peak concentration. Do this to see if it was a false positive and to see what the true value is.

Question 13

The prevalence of allergies is increasing in developed countries. What possible explanations have been suggested for this?

Answer 13

hygiene hypothesis- children too clean that they are not exposed to different antigens which affects the immune system. Other factors are vitamin D and pollution. Reduced antioxidants in the diet.

3 significant cases support this which are:

• Farmers and their children
• Siblings have better immune systems cos they pass different antigens
• Offspring of parents that come from developing coubtries that move into developed countries have a chance of more allergies showing environment does show an affect

Question 14

Signs/Symptoms

Answer 14

Skin rashes/Itching/Hives

• Swelling of the lips, tongue or throat
• Shortness of breath, trouble breathing, stridor, wheezing (bronchoconstriction)
• Dizziness and/or fainting
• Stomach pain/Vomiting/Diarrhoea
• Chest pain and low blood pressure (Vasodilation)

Question 15

Treatment:

Answer 15

• Antihistamines (Block the histamine, this will reduce bronchoconstriction and promote vasoconstriction)
• Adrenaline (Causes vasoconstriction and increases BP, Increase HR which can reverse cardiovascular collapse, also promotes bronchodilatation)
• Corticosteroids (Anti-inflammatory)
• High flow O2
• Supportive