The data on this is sort of all over the place, so I love hearing people's
experiences and opinions.
A biphasic reaction (what we're worried about) is reported to occur in as
many as 20% of patients as others have said. The 2 pediatric studies I've
read recently haven't really addressed the question of how long to observe:
Lee and Greenes looked at 108 admitted patients over 14 years at a US
tertiary center and found 6% of these *admitted* patients had some sort of
biphasic reaction, half of which were "significant". This obviously doesn't
address those patients who were seen in the ED and sent home. The one
factor they identified as being related to biphasic reaction (again,
retrospective sample, small number of "cases" of biphasic reactions, so
difficult to draw conclusions) was delay to administration of the first
dose of epi. (Pediatrics.<http://www.ncbi.nlm.nih.gov.revproxy.brown.edu/pubmed/11015520#>
Mehr et al. looked at 104 patients *admitted* from an Australian tertiary
ED with anaphylaxis and found 11% had biphasic reactions. The only
predictor for them was that those who needed more epi initially had more
likelihood of having a biphasic course (my read is, if you need more epi
now, then you might need more epi later). (Clin Exp
The most worrisome finding for me is that in studies of adults, the AVERAGE
time to onset of biphasic reaction is reported as 10 hours in a least one
The take-home for me is, good anticipatory guidance, an Epi-Pen
prescription with teaching, and crossing my fingers, knowing that if a
rebound reaction is going to happen, it could happen today or tonight or
tomorrow. And if you need more than one dose of IM epi, you're getting
On Mon, Jan 7, 2013 at 8:52 PM, Beverly Poelstra <[log in to unmask]>wrote:
> I have seen both.
> On Mon, Jan 7, 2013 at 8:00 PM, Bergmann Terence
> <[log in to unmask]>wrote:
> > I too am a community hospital ED doc, and in 22 years of full time work I
> > have not seen, or heard of anyone else I work with, having a patient with
> > this near lethal rebound. I wonder how much of it is urban myth, like
> > rebound we were going to frequently see when we gave croup kids
> > vaponephrine.
> > Terence
> > On 2013-01-07, at 3:48 PM, don zweig <[log in to unmask]> wrote:
> > > i am just a lowly non peds em doc but have treated many cases of acute
> > allergic reaction that required or benefitted from epi. i have never
> > or heard of a delayed reaction and/but have never kept a person for
> > than 2 hours observation. i do give a dose of decadron orally and send
> > hope with epipen and h2 blockers.
> > >
> > > don
> > > On Jan 7, 2013, at 11:13 AM, Doc Holiday <[log in to unmask]> wrote:
> > >
> > >> This does not sound like a bad case.
> > >> And it has been treated. The epinephrine is no longer in the system
> > there are no symptoms.
> > >> My tendency is to give 1 oral dose of prednisolone if past histoy
> > suggests severe episodes are possible for the patient AND if the allergen
> > contact has not ceased (e.g. removal of topical allergen). In this case
> > nuts are still in contact with the patient and there is a history of
> > anaphylaxis, so I'd also have given prednisolone, as was done. Then I'd
> > wait a couple of hours to be sure it's been ingested and retained and at
> > least somewhat absorbed. By "a couple" I won't insist on exactly 120
> > minutes...
> > >> Then discharge with relevant advice.
> > >> I am not aware of ANY patients who have improved, and been given
> > steroids, and then had significant "rebound".
> > >> Here is a question: When last did anyone here get called back to a
> > steroid-loaded patient they were observing, because of a rebound that
> > have made the patient return to the ED had he/she been discharged?
> > >> I am aware of 6 being the most favourite number of hours to observe
> > people, but I see no reason to prefer it to 4 or 8. My choice of 2 is to
> > make sure the patient has absorbed a significant dose of prednisolone.
> > >> We don't have any long-acting anti-histamines in our ED. We use
> > chlorpheniramine and I would advise it's use every 4-6 hours IF/AS
> > required. If I discharge the patient at bed-time, I often tell parents to
> > GIVE a dose before sleep, hoping for no disrupted sleep.
> > >> Aware of the benefit of adding H2-b, but it's only rarely required.
> > >> For my ED, by the time such a well patient is seen and then has
> > treatment is generally 30-90 minutes from arrival. If I now add even 4
> > hours of observation, I will have pressure to admit the child or have
> > him/her "breach" the 4-hour target for ED stay. This issue does not
> > what we do, but it does force us to look more closely and challenge any
> > traditional reason to cause patients to spend time in the ED... This is
> > we came to eliminate the ol' automatic "rebound" observation for asthma
> > well.
> > >> For more information, send mail to [log in to unmask] with
> > the message: info PED-EM-L
> > >> The URL for the PED-EM-L Web Page is:
> > >> http://listserv.brown.edu/ped-em-l.html
> > >
> > > For more information, send mail to [log in to unmask] with
> > message: info PED-EM-L
> > > The URL for the PED-EM-L Web Page is:
> > > http://listserv.brown.edu/ped-em-l.html
> > >
> > For more information, send mail to [log in to unmask] with the
> > message: info PED-EM-L
> > The URL for the PED-EM-L Web Page is:
> > http://listserv.brown.edu/ped-em-l.html
> Beverly A. Poelstra
> For more information, send mail to [log in to unmask] with the
> message: info PED-EM-L
> The URL for the PED-EM-L Web Page is:
Chris Merritt, MD, MPH, FAAP
Pediatric Emergency Medicine
Hasbro Children's Hospital
Alpert Medical School, Brown University
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