CTB8

Question 1

What is anaphylaxis?

Answer 1

A severe systemic allergic reaction involving respiratory and cardiovascular systems.

Question 2

What triggers anaphylaxis?

Answer 2

Allergens such as foods, insect stings, drugs (e.g., penicillin), and latex.

Question 3

How does IgE contribute to anaphylaxis?

Answer 3

IgE binds mast cells and basophils, causing degranulation upon antigen exposure.

Question 4

What mediators are released during mast cell degranulation?

Answer 4

Histamine, leukotrienes, prostaglandins, and cytokines.

Question 5

What is the physiological effect of histamine?

Answer 5

Vasodilation, increased vascular permeability, bronchoconstriction, and itching.

Question 6

What are the four classical signs of acute inflammation?

Answer 6

Rubor (redness), calor (heat), tumor (swelling), and dolor (pain).

Question 7

What is loss of function (functio laesa)?

Answer 7

A fifth sign of inflammation; severe dysfunction results in systemic collapse in anaphylaxis.

Question 8

How does anaphylaxis affect the cardiovascular system?

Answer 8

Systemic vasodilation causes hypotension and shock.

Question 9

What happens to the respiratory system during anaphylaxis?

Answer 9

Bronchoconstriction, airway oedema, and mucus production cause dyspnoea.

Question 10

Why is adrenaline the first-line treatment for anaphylaxis?

Answer 10

It reverses hypotension (vasoconstriction), bronchodilation, and mast cell stabilisation.

Question 11

What are the ABC principles of anaphylaxis treatment?

Answer 11

Airway, Breathing, and Circulation.

Question 12

What is the role of leukotrienes in anaphylaxis?

Answer 12

They sustain bronchoconstriction, inflammation, and increased vascular permeability.

Question 13

What happens to mast cells during anaphylaxis?

Answer 13

They degranulate, releasing preformed and newly synthesised mediators.

Question 14

How is anaphylactic shock defined?

Answer 14

Severe hypotension and tissue hypoperfusion due to systemic vasodilation.

Question 15

What is the function of basophils in anaphylaxis?

Answer 15

They complement mast cell responses, releasing histamine and other mediators.

Question 16

What is the role of prostaglandins in anaphylaxis?

Answer 16

They induce pain, vasodilation, and inflammation.

Question 17

What pathway leads to IgE production?

Answer 17

Th2 cells stimulate B cells to switch to IgE production in response to antigens.

Question 18

What are the symptoms of anaphylaxis?

Answer 18

Rashes, swelling, hypotension, bronchospasm, gastrointestinal distress, and dizziness.

Question 19

How is anaphylaxis diagnosed clinically?

Answer 19

By acute onset of symptoms involving skin, respiratory, cardiovascular, or gastrointestinal systems.

Question 20

What is the incidence of anaphylaxis in the population?

Answer 20

Approximately 0.05-2% of people experience anaphylaxis.

Question 21

What does adrenaline act on to restore cardiovascular function?

Answer 21

Alpha-1 receptors (vasoconstriction) and beta-2 receptors (bronchodilation).

Question 22

Why does vascular permeability increase in anaphylaxis?

Answer 22

Histamine and leukotrienes induce endothelial cell contraction, causing leakage.

Question 23

How can anaphylaxis cause laryngeal oedema?

Answer 23

Increased vascular permeability causes fluid leakage into airway tissues.

Question 24

What is biphasic anaphylaxis?

Answer 24

A recurrence of symptoms hours after the initial reaction, even with treatment.

Question 25

Why are antihistamines used in anaphylaxis management?

Answer 25

They block histamine action, reducing swelling, itching, and rash.

Question 26

What is the role of glucocorticoids in anaphylaxis?

Answer 26

They reduce late-phase inflammation and prevent recurrent symptoms.

Question 27

What are lipid mediators?

Answer 27

Molecules like leukotrienes and prostaglandins produced from arachidonic acid.

Question 28

Why is oxygen therapy important in anaphylaxis?

Answer 28

It counters hypoxaemia caused by bronchoconstriction and airway oedema.

Question 29

What is the role of tryptase in anaphylaxis?

Answer 29

Tryptase is a mast cell-specific enzyme that can confirm mast cell activation.

Question 30

Why is mast cell activation rapid in anaphylaxis?

Answer 30

Pre-formed mediators (e.g., histamine) are released immediately upon antigen binding.

Question 31

What are the key inducers of anaphylaxis?

Answer 31

Foods, drugs, insect stings, and latex.

Question 32

What mechanisms cause hypotension in anaphylaxis?

Answer 32

Systemic vasodilation and increased capillary permeability reduce blood volume.

Question 33

How does anaphylaxis affect gastrointestinal function?

Answer 33

Smooth muscle contraction causes nausea, vomiting, abdominal pain, and diarrhoea.

Question 34

How does IgE-mediated hypersensitivity differ from other types?

Answer 34

It is immediate, mediated by IgE, and causes mast cell degranulation.

Question 35

How are adrenaline auto-injectors used in emergency management?

Answer 35

They deliver intramuscular adrenaline to quickly reverse symptoms.

Question 36

Why does anaphylaxis sometimes cause wheezing?

Answer 36

Bronchoconstriction reduces airway diameter, increasing airflow resistance.

Question 37

How do cytokines contribute to anaphylaxis?

Answer 37

They amplify inflammation by recruiting immune cells.

Question 38

What are common anaphylaxis risk factors?

Answer 38

Previous allergic reactions, atopy, asthma, and exposure to known allergens.

Question 39

Why does anaphylaxis need rapid treatment?

Answer 39

It can progress rapidly to shock, respiratory failure, and death if untreated.

Question 40

What long-term strategies help prevent anaphylaxis?

Answer 40

Allergen avoidance, desensitisation therapy, and carrying an adrenaline auto-injector.

Question 41

What is the role of IL-4 in IgE production?

Answer 41

IL-4 promotes B-cell class switching to produce IgE antibodies.

Question 42

Why is adrenaline given intramuscularly in anaphylaxis?

Answer 42

IM administration provides rapid absorption and onset of action.

Question 43

What causes skin rashes and urticaria in anaphylaxis?

Answer 43

Histamine induces vasodilation and increased capillary permeability.

Question 44

How does hypoxaemia occur during anaphylaxis?

Answer 44

Airway obstruction and bronchospasm limit oxygen delivery to alveoli.

Question 45

How does anaphylaxis affect heart rate?

Answer 45

Tachycardia occurs due to compensatory sympathetic activation.

Question 46

Why can anaphylaxis lead to unconsciousness?

Answer 46

Severe hypotension and hypoperfusion impair brain function.

Question 47

How does adrenaline stabilise mast cells?

Answer 47

It reduces mediator release by acting on beta-2 receptors.

Question 48

What are the emergency steps for suspected anaphylaxis?

Answer 48

Administer adrenaline, call emergency services, provide oxygen, and monitor vitals.

Question 49

Why are beta-blockers risky in anaphylaxis?

Answer 49

They block adrenaline’s effects, reducing treatment efficacy.

Question 50

How does leukotriene receptor antagonism benefit anaphylaxis patients?

Answer 50

It blocks leukotriene activity, reducing bronchoconstriction and inflammation.