Mod12: Anaphylactic vs Anaphylactoid Reactions - Clinically Important Mediators

Question 1

_{Anaphylactic vs Anaphylactoid Reactions}

List clinically Important Mediators of Anaphylactic vs Anaphylactoid Reactions

Answer 1

Histamine

Arachidonic Acid Metabolites

Tryptase

IgE antibodies

Question 2

_{Mediators of Anaphylactic vs Anaphylactoid Reactions - Histamine}

Which receptors do Histamine affect?

Answer 2

H1 & H2 receptors

Question 3

_{Mediators of Anaphylactic vs Anaphylactoid Reactions - Histamine}

Stimulation of which Histamine receptors will cause:

Release of Nitric oxide causing vasodilation

Increased capillary permeability

Airway constriction

Smooth muscle contraction

Answer 3

H1

Question 4

_{Mediators of Anaphylactic vs Anaphylactoid Reactions - Histamine}

True or False: stimulation of H1 receptors causes vascular smooth muscle contraction

Answer 4

False

Stimulation of H1 receptors does Not cause vascular smooth muscle contraction

Question 5

_{Mediators of Anaphylactic vs Anaphylactoid Reactions - Histamine}

Stimulation of which Histamine receptors will cause:

Vasodilation, Cardiac stimulation (tachycardia), and Gastric acid secretion?

Answer 5

H2

Question 6

_{Mediators of Anaphylactic vs Anaphylactoid Reactions - Histamine}

True or False: stimulation of both H1 and H2 receptors causes vasodilation

Answer 6

True

Question 7

_{Mediators of Anaphylactic vs Anaphylactoid Reactions - Histamine}

What is the main physiologic source of Histamine?

Answer 7

Mast Cells

Histamine is also produced by Basophils

Question 8

_{Mediators of Anaphylactic vs Anaphylactoid Reactions - Histamine}

Where in the body are Mast cells abundant?

Answer 8

Airways

Skin

Question 9

_{Mediators of Anaphylactic vs Anaphylactoid Reactions - Histamine}

What’s the function of mast cells?

Answer 9

Make & release many mediators

(e.g., Histamine)

Question 10

_{Mediators of Anaphylactic vs Anaphylactoid Reactions - Histamine}

What cause mast cells to release mediators?

Answer 10

Triggered by antigens, drugs

Question 11

_{Mediators of Anaphylactic vs Anaphylactoid Reactions - Histamine}

Which specific mechanism causes mast cells to release Histamine

Answer 11

Mast cells are anchored into the tissue (airway, skin, intestin). Mast cells will have IgE antibodies on their surface. Antigens will attach to the mast cell. This will trigger the mast cell to release histamine

Question 12

_{Mediators of Anaphylactic vs Anaphylactoid Reactions - Histamine}

What percentage of circulating granulocytes are Basophils?

Answer 12

0.5 - 1%

Question 13

_{Mediators of Anaphylactic vs Anaphylactoid Reactions - Histamine}

Similar to mast cells, what do basophils have on their surface that will detect antigen (triggers) floating in the circulation and lead to Histamine release?

Answer 13

IgE

Question 14

_{Mediators of Anaphylactic vs Anaphylactoid Rx - Arachidonic Acid Metabolites}

Which two Arachidonic Acid Metabolites are associated with allergic reactions

Answer 14

Leukotrienes & Prostaglandins

^{(Breakdown products of arachidonic acid)}

Question 15

_{Mediators Anaphylactic vs Anaphylactoid Rx - Arachidonic Acid Metabolites}

Which arachidonic acid metabolites mediate allergic reactions characterized by:

• Bronchoconstriction - More intense than histamine*
• Increased capillary permeability*
• Vasodilation*
• Coronary vasoconstriction*
• Myocardial depression*

Answer 15

Leukotrienes

Question 16

_{Mediators of Anaphylactic vs Anaphylactoid Reactions}

Which arachidonic acid metabolites mediate allergic reactions that result in more intense bronchoconstriction?

A. Histamine

B. Leukotrienes

Answer 16

A. Histamine

B. Leukotrienes

Question 17

_{Mediators Anaphylactic vs Anaphylactoid Rx - Arachidonic Acid Metabolites}

Which arachidonic acid metabolites mediate allergic reactions characterized by:

Vasodilation, Bronchospasm**, Pulm HTN, Increased capillary permeability

Answer 17

Prostaglandins

Question 18

_{Mediators Anaphylactic vs Anaphylactoid Rx - Arachidonic Acid Metabolites}

Which arachidonic acid metabolites mediate allergic reactions that may result in bronchospam?

A. Leukotrienes

B. Prostaglandins

Answer 18

A. Leukotrienes

B. Prostaglandins

Question 19

_{Mediators Anaphylactic vs Anaphylactoid Rx - Tryptase}

What’s a benefit of Tryptase?

Answer 19

Serves as an excellent marker of histamine release

Question 20

_{Mediators Anaphylactic vs Anaphylactoid Rx - Tryptase}

Normally what are blood levels Tryptase?

Answer 20

Undetectable

Question 21

_{Mediators Anaphylactic vs Anaphylactoid Rx - Tryptase}

What do elevated serum levels of Tryptase indicate?

Answer 21

That mast cell activation with mediator release has occurred

Question 22

_{Mediators Anaphylactic vs Anaphylactoid Rx - Tryptase}

What trigger elevation of serum levels of Tryptase?

Answer 22

Anaphylactic or anaphylactoid reactions

Question 23

_{Mediators Anaphylactic vs Anaphylactoid Rx - Tryptase}

What’s the plasma half-life of Tryptase?

Answer 23

2 hour

Question 24

_{Mediators Anaphylactic vs Anaphylactoid Rx}

Which antibodies, present on mast cells and basophils surface cause mediator to be released?

Answer 24

Immunoglobulin E (IgE)

Question 25

_{Mediators of Anaphylactic vs Anaphylactoid Rx - IgE}

Do Anti IgE antibodies exist?

Answer 25

Yes

Anti IgE antibodies were first introduced in 2002

Question 26

_{Mediators of Anaphylactic vs Anaphylactoid Rx - IgE}

Why are Anti IgE antibodies not used more commonly?

Answer 26

Very expensive!!!

Question 27

_{Mediators of Anaphylactic vs Anaphylactoid Rx - IgE}

Anti IgE antibodies are only approved for use in which medical condition?

Answer 27

Allergic asthma

Question 28

_{Mediators of Anaphylactic vs Anaphylactoid Rx - IgE}

How are Anti IgE antibodies admnistered?

Answer 28

Parenterally

Question 29

_{Anaphylactic vs Anaphylactoid Reactions - Apex Review}

In which type of hypersensitivity allergic reaction do we note:

• Antigen antibody interaction in a patient who has been previously sensitized to the antigen.*
• IgE mediated reaction.*
• Examples: anaphylaxis, extrinsic asthma*

Answer 29

Type I: Immediate Hypersensitivity

Question 30

_{Anaphylactic vs Anaphylactoid Reactions - Apex Review}

What’s the best lab test to determine if an allergic response has occurred?

Answer 30

Tryptase

^{It is released from mast cells during an allergic reaction}

Question 31

_{Anaphylactic vs Anaphylactoid Reactions - Apex Review}

In which type of hypersensitivity allergic reaction do we note:

• IgG and IgM antibodies bind to cell surfaces or extracellular regions.*
• The reaction activates the complement cascade.*
• Examples: ABO-incompatibility, heparin-induced thrombocytopenia*

Answer 31

Type ll: Antibody-Mediated

Question 32

_{Anaphylactic vs Anaphylactoid Reactions - Apex Review}

In which type of hypersensitivity allergic reaction do we note:

• An immune complex is formed and deposited into the patient’s tissue (normally these complexes are cleared from the body).*
• The reaction activates the complement cascade.*
• Examples: snake venom reaction, protamine induced vasoconstriction*

Answer 32

Type III: Immune Complex Mediated

Question 33

_{Anaphylactic vs Anaphylactoid Reactions - Apex Review}

In which type hypersensitivity allergic reaction do we note:

• Allergic reaction is delayed at least 12 hours following exposure.*
• Examples: contact dermatitis, graft-vs-host reaction, tissue rejection*

Answer 33

Type IV: Delayed

Question 34

_{Anaphylactic vs Anaphylactoid Reactions - Apex Review}

Type IV: Delayed hypersensitivity allergic reactions are delayed for at least how long after exposure?

Answer 34

12 hours

Question 35

_{Anaphylactic vs Anaphylactoid Reactions}

Visual representation of mediators, effects and presentations

^{(see picture!!!)}

Answer 35

Note mediators, effects and presentations