Anaphylaxis and angio-oedema

Question 1

What is the definition of anaphylaxis?

Answer 1

• Severe life-threatening
• Hypersensitivity reaction: generalised or systemic
• Characterised by any or all rapidly developing problems of:
  
  • Airway
  • Breating
  • Circulation
• Usually associated with skin and mucosal changes

Question 2

Under what conditions is a diagnosis of anaphylaxis considered likely?

Answer 2

Meeting all three of the following:

• Sudden onset and rapid progression of symptoms
  
  • ‘Sense of impending doom’
• Life-threatening problems in any of
  
  • Airway: swelling; dyspnoea; dysphagia; hoarse voice; stridor
  • Breathing: SOB; wheeze; fatigue; confusion; cyaosis; SaO₂ <92%
  • Circulation: shock; tachycardia; hypotension; impaired consciousness
• Skin and/or mucosal changes
  
  • Erythema, urticaria, or angioedema

Supported by exposure to a known allergen

Question 3

What is biphasic anaphylaxis?

Answer 3

Potentially life-threatening recurrence of symptoms after initial presentation, without re-exposure to the trigger.

Question 4

Give three risk factors or triggers of anaphylaxis

Answer 4

• Pre-existing asthma: especially if poorly controlled
• Insect stings: wasps and bees
• Latex
• Food allergy
• Drugs: NSAIDs; aspirin; antibacterials; blood products; vaccines

Question 5

Outline the immediate management of anaphylaxis in children

Answer 5

• ABCDE approach; call for help esp anaesthetist
• IM adrenaline 1:1000: repeat at 5-min intervals if needed
  
  • 1m-5y: 150mcg/6-11y: 300mcg/12y+: 500mcg
• High-flow oxygen and IV fluids
• Remove trigger if possible
• Slow IM/IV chlorphenamine
  
  • 1m-5y: 2.5mg/6-11y: 5mg/12y+: 10mg
• Slow IV hydrocortisone: prevent further deterioration

Question 6

What is angio-oedema?

Answer 6

• Swelling in any of:
  
  • Deep dermis
  • Subcutaneous
  • Submucosal
• Often affecting the fact, genitalia, hands or feet

Question 7

Give three types of angio-oedema

Answer 7

• Allergic
• Non-allergic: ACEi therapy
• Hereditary
• Acquired: secondary to lymphoma or connective tissue disorder
• Idiopathic

Question 8

Outline the management of rapidly developing angio-oedema without anaphylaxis

Answer 8

• Slow IV/IM chlorphenamine
• Slow IV/IM hydrocortisone
• Arrange emergency admission

Question 9

Outline the management of stable angio-oedema without anaphylaxis

Answer 9

• Attempt to identify any underlying cause
  
  • ACEi: stop immediately; consider alternative drug (not ARBs)
• No treatment needed if mild; otherwise
• Offer non-sedating antihistamine ^eg. cetirizine
• Add prednisolone if severe
• Safety net: 999 or A+E if rapidly worsening or anaphylaxis