What is anaphylaxis?
A type I, IgE mediated life-threatening hypersensitivity reaction
What is the pathophysiology of anaphylaxis?
Release of histamine and other agents by mast cells and basophils due to IgE mediated reaction involving a specific antigen -> capillary leak and swelling
What allegens can cause anaphylaxis?
- Drugs - penicillin, contrast media, antisera
- Stings - wasps, bees, hornets
- Strawberries, Citrus fruits
What are symptoms of anaphylaxis?
What are signs of anaphylaxis?
- Laryngeal obstruction
How would you approach intially managing someone with suspected anaphlaxis?
- A - Secure airway
- B - Attach 15L/min O2, Give adrenaline IM (0.5mg), Consider salbutamol neb
- C - IV access, Fluids, Hydrocortisone (200mg), Chlorphenamine (10mg)
Admit for observation
What flow rate would you set oxygen at when treating someone with anaphylaxis?
What dose of adrenaline woul dyou give someone who was experiencing anaphylaxis?
0.5mg (0.5ml of 1:1000)
How would you administer adrenaline in anaphylaxis?
What IV access would you want to establish in someone experiencing anaphylaxis?
2 large-bore IV cannulae
How often would you repeat adrenaline injections in someone with anaphylaxis?
Every 5 mins, as guided by BP, HR, RR etc.
STOP AS SOON AS RESULT OBTAINED
What dose of hydrocortisone would you administer in someone with anaphylaxis?
How would you administer hydrocortisone?
What dose of chlorphenamine would you administer in someone with anaphylaxis?
How would you administer chlorphenamine?
What dose of nebulised salbutamol would you consider giving somoene with anaphylaxis?
What volume of saline woul dyou consider giving someone in anaphylactic shock?
500 ml over 15 mins initially, but may need 1L if hypotensive
What is the general approach to fluid administration in someone in anaphylactic shock?
Give as fast as needed and titrate to BP - may need up to 4-8L
Once initially managed, what short term management measures would you take to manage someone with anaphylaxis?
- Admit for obervation
- Continue prednisolone 30-40 mg for 3-5 days
- Continue chlorphenamine 4mg/6h PO - if itching
- Monitor ECG
- Further fluids
- Consider serum tryptase (1-6h after suspected anaphylaxis)
What would you consider as part of longer term management in someone with anaphylaxis?
- Medic alert bracelet
- Educate on self injection
- Refer to allergy clinic +/- skin prick testing to identify allergens
- Clinical incident form if allergic to antibiotic
In terms of short term management, what dose and rate of chlorphenamine would you continue somoene on until itching subsided?
How long would you continue someone on prednisolone as part of short term management of anaphylactic shock?
What dose of prednisolone woul dyou consider giving somoene as part of short term management of anaphylaxis?
What disease processes can mimic anaphylaxis?
- Systemic mastocytosis
- Hereditary angioedema
What would you do immediately once you recognised someone was having an anaphylactic reaciton?