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Study on Biphasic Reactions

2 replies [Last post]
By Lovey on Tue, 10-19-04, 14:54

This is an old study but I just came upon it recently.

[url="http://pediatrics.aappublications.org/cgi/content/abstract/106/4/762"]http://pediatrics.aappublications.org/cgi/content/abstract/106/4/762[/url]

Biphasic Anaphylactic Reactions in Pediatrics

Received Jan 3, 2000; accepted Apr 17, 2000.

Joyce M. Lee and David S. Greenes
From the Division of Emergency Medicine, Children's Hospital, Harvard Medical School, Boston, Massachusetts.

Objectives. The objectives of this study were to: 1) determine the incidence of biphasic reactions in children with anaphylaxis; 2) establish what risk factors can predict progression to a biphasic reaction; and 3) assess the utility of inpatient observation for patients whose anaphylaxis appears to have resolved.

Methods. We performed a retrospective analysis of all children admitted to Children's Hospital inpatient service between 1985 and 1999 with acute anaphylaxis. Data were collected from the medical records regarding past medical history, presenting signs and symptoms, treatment, and hospital course. Patients were considered to have resolution of anaphylaxis if they were documented to have cessation of all symptoms and needed no therapy for at least 1 hour. Biphasic reactions were defined as a worsening of symptoms requiring new therapy after resolution of anaphylaxis. Significant biphasic reactions were defined as those requiring oxygen, vasopressors, intubation, subcutaneous epinephrine, or unscheduled bronchodilator treatments. Patients were considered to benefit from a 24-hour observation period if they had a significant biphasic reaction within 24 hours of admission.

Results. Of 108 anaphylactic episodes, 2 (2%) were fatal, and 1 (1%) was a protracted anaphylactic reaction. Among the remaining 105 children with resolution of anaphylaxis, 6 (6%) [95% confidence (CI): 2, 12] had biphasic reactions, of which 3 (3%) [95% CI: .6, 8] were significant. Of those who had a biphasic reactions, the median time from the onset of symptoms to the initial administration of subcutaneous epinephrine was 190 minutes, versus 48 minutes for those without a biphasic reaction. Patients with or without biphasic reactions did not differ significantly in the incidence of initial epinephrine use, initial steroid use, or serious respiratory or cardiovascular symptoms on initial presentation. Two of 105 (2%) [95% CI: .2, 7] patients clinically benefitted from a 24-hour observation period.

Conclusions. We found an overall incidence of biphasic reactions of 6%, and an incidence of significant biphasic reactions of 3%, among pediatric patients admitted with anaphylaxis. Delayed administration of subcutaneous epinephrine was associated with an increased incidence of biphasic reactions. Approximately 2% of patients with anaphylaxis potentially benefitted from a 24-hour period of observation after symptoms had resolved. Key words: anaphylaxis, biphasic reaction, pediatric.

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By Munchkin's Mom on Wed, 10-20-04, 01:01

I just have to say OMG!

108 cases of anaphylaxis in children over a 14 year period at one hospital? That's 7-8 per year, just at that one hospital. I remember reading that anaphylaxis is severely underreported, and this certainly would seem to substantiate that.

I did some REALLY rough estimating (using Boston's population of children in 2000) and using a figure of 6% of those children as having anaphylactic allergies to something. Given that, somewhere around (again...this is REALLY rough and doesn't take about a ZILLION other factors into account) 1% of the allergic population was treated for anaphylaxis over this time period. Again, this is just at one hospital.

It really makes me wonder...if we just had more information regarding the prevalance of anaphylaxis...

Lori

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By jtolpin on Wed, 10-20-04, 14:10

I'll gladly look thru this PDF abstract, given the fact it looks interesting, and about BCH.

If there is ANY hospital to go to, in Mass., this would be the one you are transported to.

I would bet BCH is THE hospital to be treated for anaphylaxis (if transporting to them is safe)

OK. there is a BOATLOAD of reading to this case study...

Topics I see that are VERY relevant are

Biphasic time frames
Initial Epi use
Allergens (some MFA)

Cant make comments until I read the whole thing...

Probably nothing new to us, just reading material until the Sox game [img]http://uumor.pair.com/nutalle2/peanutallergy/smile.gif[/img]

Jason

ETA -- some quick bits:

'In 76 patients we were able to ascertain the time interval from exposure to the allergen to the onset of symptoms. This time interval ranged from <1 minute to 9.7 hrs.... In 75 patients we were able to ascertain the time interval from onset of symptoms to the first administration of subcutaneous epinephrine. This time interval ranged from <1 minute to 17.4 hrs'

So there was at LEAST one child (age range was from 6 mths to 21 yrs) who reacted within 1 minute, and more than likely, was the person who got the epi <1 minute as well...

How spooky... to react THAT quickly...

Yeah, I know.. we ALL react that quickly... but yikes...

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[b]* ENRICHED * [/b]

[This message has been edited by jtolpin (edited October 20, 2004).]

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