papers to read

2024 practical guide 2023 practice parameter update WAO 2020 Anaphylaxis guideline (good) Duvauchelle et al 2-18 J allergy Clin Immunolo Pract = epi pharmaco studies

+++ defintions

WAO one is quite good I like the 2 defintions, simple, probably easier for patients

some pearls:

Reactions are like a roulette. It is difficult to predict who will have a severe anaphylaxis episode vs mild it seems most cases of severe fatal anaphylaxis seem to display their first symptoms in 30 mins post ingestion

risk of death

around 1 in 1 million

cofactors:

exercise alcohol infections drugs (ie NSAIDs) emotional stress

risk factors for severe anaphylaxis

asthma on antihypertn cardiovascular diseases mast cell disorders already

ddx

vasovagal vocal cord severe asthma PE axiety MI etc...

anaphylaxis grading is variable and split ...

see WAO for their one

testing

Trytpase proteinase released by mast cells >>> basophils there is alpha and beta immature protryptase and mature tryptase with degranulation mature tryptases are released by mast cells

our test is a ELISA for 'total' trytpase max elevation 30-90 mins after onset anaphylaxis but still worth trying... correlations with hypotension in insect sting allergy should compare to baseline if possible

normal is 1-11.4 systemic is >1.2 + 2 of baseline . >20 systemic mastocytosis . >8 is HAT, mostly >11

there is some data that shows a high tyrptase is a specific but NOT sensitive marker ? 50% sensivity ...

management

beyond EPI preLOAD is important there are big changes in stroke volume and CO while HR goes up, stroke volume and preload go down

IV fluids bolus

start IV epi if refractory to a few doses of IM epi 0.1ml of 1:1000 epi and add 0.9ml of NS 1 in 10k dilution infuse it over 30-60s

doses:

12 0.5ml of 1:1000 epi 6-12 0.3 ml of 1mg/ml 1:1000 epi 0.15 for 1-5

in canada we go by weight tbh but this is from WAO

epipen and epipen junior junir is 0.15mg <30kg to 15kg... not great otherwise is 0.3

our opinion is 0.5mg is the better dose... IM

NEFFY nasal spray has some slcial chemical to allow epi to be asborebd easier through nasal mucoass seems to have a pretty good absroption profile voer time compared to autoinjector at least from componay data...

see cochrane review biphasic anaphylxais steroids limited relief

more pealrs

needle legnth is important for peds/adult don't be afriad to treat anaphylxais even if BP is high BB and epi with alpha oppostino should be kept in mind