This podcast covers anaphylaxis, have a listen and let us know what you think. Below are a few of the key take home messages, enjoy!
The most common causes of fatal reactions identified in the UK are (Pumphrey 2004):
- stings, nuts and “other foods” e.g. milk and shellfish.
- Anaesthetic drugs
- Other drugs e.g. NSAIDS and ACE-I
- Contrast media
Fatal reaction occurred quickly, with time to arrest demonstrated below (Pumphrey 2000):
- Injected drugs = 1-20 minutes
- Stings = 2-45 minutes
- Food = 10-100 minutes (most deaths 10-45 minutes)
The mainstay of treatment is adrenaline (1:1000 concentration, given IM) at the doses below (RCUK) and can be repeated every 5 minutes:
- Adult = 500 micrograms IM (0.5mls)
- Child more than 12 years = 500 micrograms IM (0.5mls)
- Child 6-12 years = 300 micrograms IM (0.3mls)
- Child less than 6 years = 150 micrograms IM (0.15mls)
(Cochrane review for adrenaline available from Sheikh et al 2008)
- H1-antihistamines = no evidence to support their routine use in anaphylaxis (Sheikh et al 2007). Some evidence of improved skin signs e.g. itching for less severe reactions. Important to remember they can also cause drowsiness, confusion, fatigue and dizziness as side effects.
- H2-antihistamines = no evidence to support their routine use in anaphylaxis (Nurmatov et al 2014). May provide some relief for less emergent skin symptoms.
- Steroids (glucocorticoids) = no evidence to support their routine use in anaphylaxis (Choo et al 2012). The primary reason for administration has been to prevent biphasic reactions (see below), however a recent paper by Grunau et al (2015) found they were not associated with decreased relapses within 7 days.
A huge study by of 430,000 casenotes by Grunau et al (2014) found biphasic reactions were incredibly rare (0.17%!) but could occur far longer than any reasonable period of observation in the ED (anything up to 6 days afterwards). Additionally there were NO fatalities.
Choo, K. J., Simons, F. E & Sheikh, A (2012). Glucocorticoids for the treatment of anaphylaxis. Cochrane Database of Systematic Reviews. Apr 18 (4): CD007596 (available at http://www.ncbi.nlm.nih.gov/pubmed/22513951 ).
Grunau, B. E., Li, J., Yi, T. W., Stenstrom, R., Grafstein, E., Weins, M. O., Schellenberg, R. R & Scheuermeyer, F. X (2014). Incidence of clinically important biphasic reactions in emergency department patients with allergic reactions or anaphylaxis. Annals of Emergency Medicine. 63 (6), pp736-44 (available at http://www.ncbi.nlm.nih.gov/pubmed/24239340 ).
Grunau, B. E., Wiens, M. O., Rowe, B. H., McKay, R., Li, J., Yi, T. W., Stenstrom, R., Schellenberg, R. R., Grafstein, E & Scheuermeyer, F. X (2015). Emergency department corticosteroid use for allergy or anaphylaxis is not associated with decreased relapses. Annals of Emergency Medicine. 66 (4), pp381-9 (available at http://www.ncbi.nlm.nih.gov/pubmed/25820033 ).
Nurmatov, U. B., Rhatigan, E., Simons, F. E & Sheikh, A (2014). H2-antihistamines for the treatment of anaphylaxis with and without shock: a systematic review. Annals of Allergy, Asthma and Immunology. 112 (2), pp126-31 (available at http://www.ncbi.nlm.nih.gov/pubmed/24468252 ).
Pumphrey, R. S (2000) Lessons for the management of anaphylaxis from a study of fatal reactions. Clinical and Experimental Allergy. 30 (8), pp1144-50 (available at http://www.ncbi.nlm.nih.gov/pubmed/10931122 )
Pumphrey, R. S (2004) Fatal anaphylaxis in the UK, 1992-2001. Novartis Foundation Symposium. 257, 116-28 (available at http://www.ncbi.nlm.nih.gov/pubmed/15025395 ).
Sheikh, S. A., ten Broek, V. M., Brown, S. G & Simons, F. E (2007). H1-antihistamines for the treatment of anaphylaxis with and without shock. Cochrane Database of Systematic Reviews. Jan 24 (1): CD006160 (available at http://www.ncbi.nlm.nih.gov/pubmed/17253584 ).
Sheikh, A., Shehata, Y. A., Brown, S. G & Simons, F. E (2008) Adrenaline (epinephrine) for the treatment of anaphylaxis with and without shock. Cochrane Database of Systematic Reviews. Oct 8 (4): CD006312 (available at http://www.ncbi.nlm.nih.gov/pubmed/18843712 ).