Adult Anaphylaxis

Question 1

What are the 5 most common Allergens

Answer 1

1. Insect stings
2. Food
3. Medication
4. Exercise-induced
5. Idiopathic

Question 2

When should escalation of care be considered in Anaphylaxis?

Answer 2

• Expected clinical course (Refractory Anaphylaxis, ICU admit, multiple adrenaline doses)
• Hypotensive <90
• Medication as percipitating cause (Abx, IV contrast medium)
• Respiratory symptoms
• Hx of asthma or multiple co-morbidities
• No response to initial dose of IM Adrenaline

Question 3

Where should adrenaline be administer in a patient with anaphylaxis?

Answer 3

Antero-lateral thigh

Question 4

What are signs of Adrenaline toxicity?

Answer 4

• shaking
• tachycardia
• nausea
• vomitting
• arrhythmias

Question 5

When should glucagon be administered in an anaphylactic patient?

Answer 5

• patients remaining hypotensive after 2 adrenaline doses
  And
• history of heart failure
  OR
• patients in beta-blocker

Question 6

What is the Pathophysiology of Anaphylaxis

Answer 6

1. Initial exposure to Antigen
2. Antigen presenting cells present antigen to T-helper cells
3. T helper cells stimulate B-cells to differentiate into plasma cells and memory cells
4. Small release of IgE from plasma cells
5. Re-exposure causes mass inapprorpriate mast cell activation due to cross-linking of IgE to High affinity IgE receptors on mast cells
6. Mast cells release pro-inflammatory mediators (Histamine, Prostoglandins, TNF)
7. pro-inflammatory mediators cause Vasodilation, Increased Vascualr permeability, Bronchoconstriction, Increased mucous secretion
8. This can lead to Hypotension, Airway compromise, Angiodema, Cramping, rashs
9. Shock
10. MODS
11. Coma
12. Death

Question 7

What is the intitial Mx for Anaphylaxis ?

Answer 7

1. Remove antigen
2. Adrenaline 500mcg @ 5/60 intervals
3. Oxygen (As per critical illness)
4. Request MICA if high risk symptoms OR not responsive to initial Adrenaline
5. Insert IV

Question 8

What is the Management for Airway Oedema/Stridor in Anphylaxis ?

Answer 8

1. Adrenaline 5mg Nebulised
   - Consult with clinician for repeat dose if required
   - Notify receiving hospital

Question 9

What is the Management for Bronchospasm in Anphylaxis ?

Answer 9

1. Salbutamol 5mg Nebulised
   - Repeat @ 20-minute intervals
2. Atrovent 500mcg Nebulised
3. Dexamethasone 8mg Iv/Oral

Question 10

What is the Management for Cardiovascular in Anphylaxis ?

Answer 10

• BP <90 despite initial Adrenaline
  1. Normal Saline (40ml/kg)
• Consult for more or 20ml/kg