Anaphylaxis

Question 1

Definition

Answer 1

A serious allergic reaction that is rapid in onset and can cause death

Question 2

Prevelance

Answer 2

1-3 reactions per 10,000 people

Question 3

Presentation

Answer 3

Urticaria, syncope, anxiety, angio-oedema, itching, stridor and wheezing, palpitations, low BP

Question 4

Diagnosis(3)

Answer 4

Diagnosing anaphylaxis must fulfil one of these 3 criteria:

Acute onset of illness with involvement of skin, mucosal tissue or both

Two or more of the following : involvement of skin-mucosal tissue, resp compromise, reduced BP or persistent GI symptoms

Reduced BP after exposure to known allergen for that patient.

Question 5

Causes

Answer 5

Foods, venom, drugs

Question 6

Pathophysiology

Answer 6

During a TYPE 1 REACTION, an allergen reacts with specific IgE antibodies on mast cells and basophils which triggers rapid released of mediators such as histamine, tryptase and PAF which cause symptoms

Question 7

Investigations

Answer 7

Serum tryptase is preferred marker, but only remain elevated for approx 6 hours

Question 8

Management - acute

Answer 8

CHAOS as acute treatment

C – cetirizine IV or IM (antihistamine)

H – hydrocortisone IV or IM

A – adrenaline adult dose is 0.5mg, child dose of 6-12 yrs. is 0.3mg and below 6 is 0.15mg

O – oxygen, high flow

S – salbutamol

And give rapid IV fluid – Hartmann’s or 0.9% saline in 5-10 mins

Question 9

Management - longer term - 4

Answer 9

Create an allergy action plan

Patient carries allergy id

Carry adrenaline auto-injector everywhere

Avoid allergen

Question 10

Differentials (4)

Answer 10

Asthma attack,
septic shock,
panic attack,
breath-holding episode in a child