1. Mohan Kamalanathan Emergency Department Frankston Hospital
Anaphylaxis
Mohan Kamalanathan
Emergency Department
Frankston Hospital

2. Introduction Definition. Statistics. Treatment. Current trends.
Controversies.

3. Definition. ān'ə-fə-lāk'sĭs
Hypersensitivity especially in animals to a substance, such as foreign protein or a drug, that is caused by exposure to a foreign substance after a preliminary exposure.
Richet and Porter in 1902

4. Statistics. ED presentations vary between 1 in 440 to 1 in 1500.
Fatalities vary between 3 to 9% of presentations.
True incidence in unknown as numbers are underestimated.

5. Variations in anaphylaxis.
True anaphylaxis.
Anaphylactic shock.
Anaphylactoid reaction.

6. Clinical features. Cutaneous Respiratory Cardiovascular
Gastrointestinal
Other

8. Pathophysiology.

9. Airway oedema.

10. Cutaneous features.

11. Treatment. First line medication. Position patient. Oxygen Adrenaline
Supine or left lateral.
Oxygen
Keep sats > 92%.
Adrenaline
0.3 – 0.5 mls of 1:1000 IM.
Repeated 5 minutely.
Fluids
Anything will do.

12. Treatment Second line treatment: Antihistamines Steroids Glucagon
H1 or H2 antagonists.
Steroids
Oral vs. intravenous.
Glucagon
1 mg IV repeated every 5 minutes.
Bronchodilators
Salbutamol or Adrenaline

13. Level of evidence in anaphylaxis.
Use of Oxygen:
Really good idea
No one has challenged it.

14. Adrenaline Cornerstone.
Lateral thigh IM injection better than other IM routes as serum levels reliably achieved in 3 – 5 minutes.
Level 3 evidence.
Continuous infusion safer than boluses.

15. Fluids. 20 ml/kg over 1 – 2 minutes.
No direct evaluation between colloid or crystalloid.
Any fluid will do.

16. Antihistamines.
H2 antagonists (Ranitidine) help with the urticaria of anaphylaxis.
Level 3 evidence.
H1 antagonists (Promethazine) going out of fashion due to excessive sedation, vasodilatation and hypotension.
Current trend is to use non-sedating H2 antihistamines.

17. Steroids.
Current practice is to use 250 mg Hydrocortisone intravenously.
No comparative trials between methylprednisolone or dexamethasone.
Thought to be useful for prevention of late phase occurrence.

18. Glucagon. Coming into vogue now.
Useful in pretreatment of a subgroup of patients with anaphylaxis.
1 mg intravenously.

19. Bronchodilators. Salbutamol. Adrenaline. Nebulised 5 mg with oxygen.
Useful as a temporising measure.
Adrenaline.
Nebulised 5 mls 1:1000 undiluted.
Another temporising measure.

20. Controversies in anaphylaxis.
Dilution of adrenaline dose.
Observation period of 8 hours.
Biphasic anaphylaxis is 1 – 5%.
Use of mast cell tryptase to confirm diagnosis.

21. Key points. Adrenaline is main treatment.
All other treatments are unproven in anaphylaxis, but are a good idea.
Drugs coming in vogue are:
Non-sedating antihistamines.
Glucagon.

22. Rules to live by.
-I work very hard. Please don't expect me to think as well.
-Love your enemies. At least they don't try to borrow money from you.
-There is no job so simple that it can not be done wrong.
-In order to keep an open mind, I am trying to avoid learning anything.
-I have seen the truth, and it makes no sense!
-Never underestimate the power of human stupidity.
-Never wrestle a pig. You both get dirty and the pig likes it.
-If your only tool is a hammer, all your problems start to look like nails.
-If you're not part of the solution, be part of the problem!
-If you can not convince people, confuse them!