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Anaphylaxis is one of the most under-appreciated and under-treated conditions in the Emergency Department. A common misperception is that you need hypotension to diagnose it. Below is a brief summary of the diagnostic criteria and ED treatment protocol. Immediate administration of IM epinephrine is critical.
A major challenge is deciding which patients can go home and which need to be admitted, because of the risk of "rebound" or a biphasic anaphylactic response. This may occur as late as 72 hours later, but typically occur within the first 24 hours. There isn't a good answer for this.
What's your practice in dispositioning these patients? Personally, I admit at least those patients who present with severe hypotension, require more than 1 epinephrine dose, or have poor social support.
NOTE: Unlike the photo on the top, warn patients not to rest their thumb on the device because of the risk inadvertent needle puncture.
Hey Michelle, great post on a "bread and butter" emergency medicine topic.
ReplyDeleteOne question, if you have somebody with a severe anaphylactic reaction in refractory shock even after 2 x IM Epi do you then go to Epi IV? If so, what dosing do you use?
Thanks!
Good question. I still follow the 2005 American Heart Association guidelines (which reference a 1984 JAMA article):
Delete"Use epinephrine (1:10 000) 0.1 mg IV slowly over 5 minutes. Epinephrine may be diluted to a 1:10 000 solution before infusion. An IV infusion at rates of 1 to 4 μg/min may prevent the need to repeat epinephrine injections frequently."
To translate, that means 0.1 mg of 1:10,000 epi = 1 mL over 5 min. Note that this concentration of epi is 10x more dilute than the IM epi which is 1:1,000. Common medication error is to give this more concentrated epi formulation in IV form, cause an overdose of IV epi.
@Hans: And yes, after 2 IM doses of epi, I do go to IV.
DeletePerfect. Thanks!
DeleteDr Lin,
ReplyDeleteJust something to point out with the photo...I've seen a couple of people (docs included) inject their thumb by accident when they held the injector this way (rather than keeping their thumb off the end) in the heat of the moment. Have you seen that as well?
@Mark: Good question. Sadly I've heard of such cases, but haven't actually managed such a case. Typically only supportive care is necessary. For extremely cases some case reports suggest phentolamine.
ReplyDeletehttp://www.ncbi.nlm.nih.gov/pubmed/11902698:
Mrvos R, Anderson BD, Krenzelok EP. Accidental injection of epinephrine from an autoinjector: invasive treatment not always required. South Med J. 2002 Mar;95(3):318-20.
BACKGROUND: Individual case reports of accidental injection with epinephrine
appear in the literature and seem to represent the worst case scenarios. We
present a case series of 28 exposures to epinephrine via autoinjector.
METHOD: All accidental parenteral injections of epinephrine by autoinjector
reported to two regional poison information centers over a 2-year period were
included.
RESULTS: Injection sites included digits (23 cases), palm (4 cases), and thigh (1
case). Symptoms included swelling, pallor, pain, and erythema. Four patients
reported no effect, and 9 required no treatment. Ten patients obtained relief
with warm soaks, 1 patient had massage only, and 2 patients were lost to
follow-up. Fourteen were examined in the emergency department, and 14 were
treated at home.
CONCLUSION: Although some injection injuries must be treated in an emergency
facility, many can be treated at home. Immediate referral to a health care
facility is not needed in all cases and at times is unwarranted.
Hi Michelle, in our Australian ED we have a rough policy (without much evidence base I admit) that if the patient got adrenaline then they need to stay for a least 6 hours post resolution of symptoms, and if the the end of that period is "late" at night (after 10-11 PM) then they stay overnight in the observation ward. Immunologists seem to be happy with this plan. Probably too overcautious, and I've never seen a delayed recurrence. Not to say I won't one day...
ReplyDeleteThis policy sounds like a very reasonable plan. I've had a colleague who has had 3 24-hour bouncebacks with a delayed recurrence in her very early career. All did fine but they were pretty impressive presentations on recurrence requiring epi again. Thanks for sharing your ED's approach.
DeleteThanks. I wish these procedures would be adopted by all ERs. Many of us with kids with life-threatening allergies have to convince doctors of the new treatment protocols.
ReplyDeleteAgreed, I think we're slowly changing culture.
Deletemy basic pathway:
ReplyDelete-if you have any airway involvement, 4-6h obs
-if >1 dose of epi = admit
-if 2nd dose of epi doesnt immediately fix everything, epi gtt
plus all the usual steroids, h1, h2. will throw mag at them around the same time as the 2nd epi dose
Excellent protocol. I also put GLUCAGON on my list just in case you have epi-refractory hypotension from beta-blocker use.
DeleteGreat summary!
ReplyDeleteWhat's your current practice with regard to prescribing steroids at discharge? I find there's so much discrepancy between dosing, tapering, and duration of treatment.
Thanks!
Excellent question. There is actually NO evidence even looking at corticosteroids for the treatment of acute anaphylaxis. There's also no evidence available in whether it can reduce the incidence of the biphasic response of anaphylaxis. That's why there's so much practice variation. I've personally seem people prescribe 3-14 days of prednisone (burst and tapered approach).
DeleteThat being said, I personally DO add corticosteroids (usually 40-60 mg daily) on discharge for 5 days, similar to a burst treatment used in asthma and COPD exacerbation. The trick is to warn the patient that despite maximal medical therapy at home, the anaphylaxis symptoms may return quickly within 72 hours and that it's important to return to the ED immediately if that happens.