Allergy reaction - what's your epinephrine threshold?

[pinipig523]

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So, here's how I was trained - once there is vasomotor instability or signs of anaphylaxis (systemic symptoms such as vomiting, syncope) then give epi in addition to the usual allergy meds.

That said - I was wrestling with the idea that one of my patients had an intact airway but HE felt like his tongue was very swollen from the posterior onwards. Now, I stuck with my guns and didn't give epinephrine and he did well on my usual allergy cocktail (benadryl, pepcid, solumedrol or prednisone).

It's easy to know when you HAVE to give epi... but when you're at the grey zone, it's a little tougher.

What's YOUR threshold for EPI? Is it tongue swelling or significant FB sensation in the posterior pharynx? Is it vocal change?

 

[Khaos]

I do not have a high threshold for epi in a younger patient without significant past medical history. I will give it to them if they have diffuse rash, any symptoms at all with lip/tongue/posterior pharynx swelling, sensation of any of them, or wheezing. You have to remember that before albuterol and atrovent, epinephrine was given all of the time with very few complications.

Now, you have an older patient with risk factors for CAD, then I am a little bit more hesitant and if I do give them epi, I give them 0.3ml of epi IM. This is usually enough to help with the allergic reaction but hardly causes worsening tachycardia (usually if I'm giving it to someone like that they are anxious and have tachycardia already).

 

[xaelia]

No hesitation to give epinephrine for someone sufficiently uncomfortable.

 

[deleted109597]

I give it almost every time. Unless they're elderly with cad and chest pain. Even then I give it IM or subq.

It isn't dangerous, and you're doing your allergy AND urticaria patients a disservice by not considering it. Benadryl, pepcid, and steroids takes hours. Epi is almost instantaneous.

 

[dotcb]

If multi-system involvement (even just symptoms) - I give IM epi.

If high risk for CAD and the patient does not clearly need epi, I would likely hold off and observe.

In young patients and low CV risk, I'll give epi even just for bad urticaria. Just talk about it with the patient.

Never had a problem yet - after all, the epi pen is designed to be self-administered at home.

 

[jendc08]

How long are you observing after epi?

 

[deleted109597]

How long are you observing after epi?

For anaphylaxis? 4 hours. For anything else? Maybe an hour. What are you worried about, rebound itching?

 

[docB]

Maybe I'm in the minority but I almost never use epi for allergic reactions. The real anaphylactoid reactions are very rare and using it on the minor reactions turns a short visit into a long visit for the post treatment obs. It seems like most of the "severe" symptoms I see are anxiety mediated and that will not be helped by the epi.

 

[deleted109597]

Don't get me wrong. I don't use it for the allergies that get meds listed in the EMR (nausea, abdominal pain, lack of getting high).

I use it for true anaphylaxis, and for actual mast cell mediated reactions like urticaria. I don't use it for angioedema.

 

[suckstobeme]

If the pt described in the above post wasn't an older person or one that had known CAD or underlying arrhythmia, I totally would have given Epi. I haven't really had any bad experiences with it. I've never caused a cardiac event or precipitated an arrhythmia. In general, in a healthy patient, allergic reaction + Mod discomfort OR any throat swelling/facial (even if it's just a sensation) OR any SOB or wheezing, I will probably give Epi. And I send many (though not all) of my patients home with EpiPens; more than my colleagues do.
Also, though I haven't looked into this for awhile, my understanding is that Epi is one of the few things that actually work for angioedema; a lot of angioedema is not histamine related so steroids and anti-histamines don't work very well.

 

[deleted109597]

Also, though I haven't looked into this for awhile, my understanding is that Epi is one of the few things that actually work for angioedema; a lot of angioedema is not histamine related so steroids and anti-histamines don't work very well.

Sorry, I meant bradykinin mediated angioedema (no anaphylaxis). You can tell the difference because people with anaphylaxis have hypotension and itch.
And epi works for anaphylaxis. As do steroids and anti-histamines.

It doesn't work at all for ACE induced or hereditary angioedema. Only the expensive C1 esterase, kallikrein, or that other recombinant drug really work for that condition.

 

[WilcoWorld]

I agree that epi (and steroids, and antihistamines) is ineffective in bradykinin mediated angioedema.
Icatibant is attractive, but I haven't had a chance to use it yet, as I've never worked at a hospital that had it.

 

[WilcoWorld]

Oh yeah, the main point of the thread:
My threshold for the use of epi in anaphylaxis has gotten lower as my experience has increased. In kids, I'm not at all reluctant to give it for as "little" as generalized urticaria that's refractory to benadryl (in such cases epi works like a miracle drug - you can watch the rash improving). The oldest person I've given it to for diffuse urticaria was a guy in his 60's. He was a physician, had no CAD Hx, and we talked about the pros and cons before administering it.

Would I give it in someone with known CAD? It depends. Not in someone with a tight stenosis that wasn't stented due to technical difficulty who is now holding his pressure and his airway. But someone who has a single stent who is now getting hypotensive? Heck yes. Sure, catecholamine surges aren't good for someone with CAD, but a MAP<65 isn't very good for someone with CAD either.

Think about it this way - diffuse urticaria = massive vasodilation, which steals a LOT of your cardiac output. So giving 0.3mg of epi might actually decrease the strain on the patient's heart.

That all being said, so long as they're stable I'll always try benadryl first. If that works, I'll skip the epi.

 

[Extracts]

As an allergist, we have a mantra for using epi in suspected anaphylaxis "when in doubt, whip it out".

For any suspected anaphylaxis/anaphylactoid (systemic reaction involving cardiac, respiratory (upper/lower), GI, and or cutaneous) reaction, give epinephrine. There is an increase in mortality/morbidity with delay in epinephrine administration.

Anaphylactoid reactions are caused by direct mast cell histamine release. Not IgE mediated but still treated with epinephrine (full dose IM 0.3 ml)

For elderly patients with CAD with suspected anaphylaxis give epinephrine. If you're thinking MI vs death. I would choose MI. Epi is also short acting.

For the above scenario, if they have CAD, they are probably on a beta-blocker. If symptoms are refractory to epi (after multiple administration) give glucagon.

We love having EM transitional residents rotate through our department. We teach them that anaphylaxis is not treated by anti-histamines/steroids and epi is the first line treatment for any suspected anaphylaxis.

 

[pinipig523]

As an allergist, we have a mantra for using epi in suspected anaphylaxis "when in doubt, whip it out".

For any suspected anaphylaxis/anaphylactoid (systemic reaction involving cardiac, respiratory (upper/lower), GI, and or cutaneous) reaction, give epinephrine. There is an increase in mortality/morbidity with delay in epinephrine administration.

Anaphylactoid reactions are caused by direct mast cell histamine release. Not IgE mediated but still treated with epinephrine (full dose IM 0.3 ml)

For elderly patients with CAD with suspected anaphylaxis give epinephrine. If you're thinking MI vs death. I would choose MI. Epi is also short acting.

For the above scenario, if they have CAD, they are probably on a beta-blocker. If symptoms are refractory to epi (after multiple administration) give glucagon.

We love having EM transitional residents rotate through our department. We teach them that anaphylaxis is not treated by anti-histamines/steroids and epi is the first line treatment for any suspected anaphylaxis.

Thanks for chiming in!

But you're saying - save the EPI for a true anaphylactic/anaphylactoid event, right? A little rash and a little FB sensation in the back of the throat does not constitute EPI - am I correct?

Problem I have w/ EPI is that it becomes a long waiting/obs period in the ER and I've seen 2 patients go into VTACH from it. I try to stay away and I've only had to use EPI 5x in my career thus far for anaphylaxis. 98% of the time, they get better with just the usual cocktail and observation for 2 hours in the ER.

OTOH, I send all my allergy reactions home w/ EPIpens and an allergy f/up.

Btw, you guys admit for 23h obs if you had to give someone or some kid 2 EPI shots in the ER, right?

 

[docB]

We're talking about several different things here and they're getting all mashed together (one of the limitations of the medium). Anaphylactoid reactions where the patient looks sick (e.g. hypotension), patients who have urticaria and are uncomfortable but not unstable and "other" where the patient complains of feeling they are having symptoms but there is no objective evidence of it. I agree with epi with the anaphylactoid reactions and the angioedemas. For just urticaria I'm reluctant to use epi because of the side effects and the obs time. I wouldn't give it to the worried well.

And how long are people obsing these patients post epi?

 

[deleted109597]

Thanks for chiming in!

But you're saying - save the EPI for a true anaphylactic/anaphylactoid event, right? A little rash and a little FB sensation in the back of the throat does not constitute EPI - am I correct?

Problem I have w/ EPI is that it becomes a long waiting/obs period in the ER and I've seen 2 patients go into VTACH from it. I try to stay away and I've only had to use EPI 5x in my career thus far for anaphylaxis. 98% of the time, they get better with just the usual cocktail and observation for 2 hours in the ER.

I haven't ever seen VT from epi personally.
I do know of someone getting a STEMI from it (clean cath though). Don't give code drug dose IV unless the patient is coding.

Hell, I've put people on epi drips to keep from intubating them.

Why the long obs period? Again, you watch life threatening anaphylaxis because the rebound is, uh, life threatening anaphylaxis. For urticaria? The rebound is itching. Big deal. Send 'em home.

 

[WilcoWorld]

DocB makes good point. So here goes:

"I think I might be having an allergic reaction" - maybe benadryl, maybe nothing
"I have an itchy rash on my arm" - PO benadryl, no epi or steroids
"I'm hot & red in a few places, but my throat feels normal" - PO benadryl and steroids, epi will depend on the severity of the urticaria, the comorbidities and the response to benadryl
"I'm hot and red all over, and my throat/tongue feels funny" - 0.3mg epi IM now, parenteral steroids and benadryl (because the gut's not well perfused when your skin is glowing red)

If I give them epi I watch for 4 hours. If they're doing well I d/c with an epi pen Rx. If they rebound and I need to redose the epi before 4 hours, I admit.

 

[Extracts]

Again I'm not an ER doc but if you reach a threshold where you believe there is true anaphylaxis/anaphylactoid reaction requiring epi, I would admit this person. There is a late phase reaction with anaphylaxis that can occur 12 hours after. Therefore observation for 4 hrs would give you a false sense of security.

 

[pinipig523]

Again I'm not an ER doc but if you reach a threshold where you believe there is true anaphylaxis/anaphylactoid reaction requiring epi, I would admit this person. There is a late phase reaction with anaphylaxis that can occur 12 hours after. Therefore observation for 4 hrs would give you a false sense of security.

If you're having to admit every patient post-EPI, you're admitting a lot of patients.

 

[Extracts]

How many patients do you give epi to on a daily basis?

 

[The White Coat Investor]

So, here's how I was trained - once there is vasomotor instability or signs of anaphylaxis (systemic symptoms such as vomiting, syncope) then give epi in addition to the usual allergy meds.

That said - I was wrestling with the idea that one of my patients had an intact airway but HE felt like his tongue was very swollen from the posterior onwards. Now, I stuck with my guns and didn't give epinephrine and he did well on my usual allergy cocktail (benadryl, pepcid, solumedrol or prednisone).

It's easy to know when you HAVE to give epi... but when you're at the grey zone, it's a little tougher.

What's YOUR threshold for EPI? Is it tongue swelling or significant FB sensation in the posterior pharynx? Is it vocal change?

I have an ultra low threshold because it makes people feel so much better so quickly. It is an exceedingly safe drug given IM in the appropriate dose. I challenge you to find a case where an appropriate dose of IM epi caused someone harm. I'm sure they're out there, but I haven't found them yet. Most allergic reactions are patients with zero heart problems.

You got a really itchy rash? Good enough for me. I would say MOST of my allergic reactions get epi.

 

[Extracts]

I have an ultra low threshold because it makes people feel so much better so quickly. It is an exceedingly safe drug given IM in the appropriate dose. I challenge you to find a case where an appropriate dose of IM epi caused someone harm. I'm sure they're out there, but I haven't found them yet. Most allergic reactions are patients with zero heart problems.

You got a really itchy rash? Good enough for me. I would say MOST of my allergic reactions get epi.

Management patterns differ and some physicians are more conservative than others. Just know that the first line of treatment for suspected anaphylaxis (ie. systemic reaction) is epinephrine.

I agree that you can't go wrong with giving it, but you can definitely have an adverse event withholding it.

 

[Extracts]

Thanks for chiming in!

But you're saying - save the EPI for a true anaphylactic/anaphylactoid event, right? A little rash and a little FB sensation in the back of the throat does not constitute EPI - am I correct?

Problem I have w/ EPI is that it becomes a long waiting/obs period in the ER and I've seen 2 patients go into VTACH from it. I try to stay away and I've only had to use EPI 5x in my career thus far for anaphylaxis. 98% of the time, they get better with just the usual cocktail and observation for 2 hours in the ER.

OTOH, I send all my allergy reactions home w/ EPIpens and an allergy f/up.

Btw, you guys admit for 23h obs if you had to give someone or some kid 2 EPI shots in the ER, right?

I'm a little more conservative. A rash (usually with anaphylaxis, cutaneous manifestations are not usually little) with upper airway symptoms technically constitutes a systemic reaction with two organ involvement. Again, there are many gray zones in medicine, but I would give epinephrine in this scenario.

I'm glad that you send all suspected anaphylaxis patients with epinephrine with further evaluation. You also can't go wrong with prescribing epinephrine, but then again I'm biased!.

A kid who receives two epi pens definitely needs admission or at the very least overnight observation in my opinion.

Hope that helps.