Unit 1: Preventing, Recognizing and Treating Anaphylaxis.

Preventing, Recognizing and Treating Anaphylaxis

Case Presentation

A 27 year old male graduate student consults you for runny itchy congested nose and itchy watery eyes, present for many years but much worse over the past 2 years.  Spring and fall are the worst.  Antihistamines improve but do not eliminate symptoms.  He’s also noticed a little shortness of breath when running, but concedes that it may be a deconditioning issue.  His only other health issue is very mild hypertension, and his blood pressure today is normal on his daily antihypertensive medication.  He’s been off all allergy medications for 2 weeks.  You offer him skin testing, and he accepts.

You assure an adequate histamine response (9mm wheal) and proceed to put on the 38 chosen antigens of your initial panel.  When you check on the patient at about 10 minutes after putting  on the skin tests, you notice numerous large (10-15mm) wheals with surrounding erythema. He says he feels fine.  Five minutes later, your nurse interrupts as you are seeing another patient, saying I need you in Room 2.  You walk in to find your patient looking visibly uncomfortable, with a flushed slightly swollen face.  He says “I feel really funny”- you notice his voice is a little hoarse.  

You diagnose an early systemic reaction, and immediately give him 50 mg of chewable diphenhydramine and 4 puffs of albuterol.  One minute later, he seems to be getting a little confused. HIs blood pressure is 105/60.  You administer IM epinephrine, with immediate improvement.  

Note**  This prequiz may contain questions about topics with which you are totally unfamiliar.  That’s OK.  In addition to helping you gauge your knowledge, these questions perform a ‘priming’ function making your neural pathways more receptive for learning this content!!

Q1:  Which would you do next?

  1. Have him transported by ambulance to the ED for any further treatment and observation
  2. Start an IV, and administer another 25 mg of diphenhydramine along with 10 mg of solucortef.
  3. Give him a prescription for 20 mg of prednisone this evening, 20 mg in the morning, and send him home.
  4. Have him call a friend to drive him back to his apartment.  Tell him he’ll feel OK in the morning.
  5. Prescribe another Epipen for him to take home with him in case the symptoms reoccur.

A1:  A.  Although steroid may be helpful in resolving the inflammation, this medication will not prevent a biphasic response.  (Lewis 2014)   Recent literature indicates that 5-6 hours of ED observation is appropriate for most of these patients.
B:  You could do this, but what he really needs now is hours of observation
C:  No.  You don’t want him to experience a biphasic worsening at home, alone.
D:  Well, C was a marginally better choice than this.  No.
E:  Yes, of course, but A comes first!!

Q2:  If his antihypertensive medication is a beta-blocker, how might this have affected his clinical course?

A2:  When epinephrine is administered to a beta-blockaded patient, it provides mostly alpha stimulation.  Some think this means the dose of epinephrine should be halved in beta-blockaded patients, others think it should be doubled to ‘overcome’ the beta blockade.  You certainly should have determined exactly which antihypertensive he is on.  It is most prudent to have the patient off any beta-blocker (general OR cardio-selective) for 1-2 days prior to allergy skin testing.

Q3:  True or False?  Epinephrine for anaphylaxis is preferentially administered subcutaneously.

A3:  No.  That used to be thought best, but further studies showed the epinephrine is absorbed more rapidly from muscle than subcutaneous tissue.  

Q4:  What are some methods you might have further evaluated his breathing prior to allergy skin testing?  Why would you care?

A4:  Studies show that adverse generalized reactions to allergy testing and immunotherapy are more common when breathing is not as well controlled as it could be. (Epstein 2014)   Ideally you would have asked him about any childhood asthma, former or current exercise intolerance, asthma medication use and any current chest tightness, wheezing, shortness of breath or cough, especially cough awakening him at night.  

Option 1:  Auscultation:  Any wheezing, rales, ronchi or other abnormal sounds would cue you that further assessment is needed prior to testing.
Option 2:  Peak Flow-  comparing his performance to normative values would tell you if his baseline exhalation was as expected for his age and gender.
Option 3:  Fractional Exhaled Nitric Oxide (FeNO).   This is a marker of eosinophilic lung inflammation.  A higher-than-normal valued would have prompted you to further investigation.
Option 4:  Spirometry:  A basic flow-volume loop would tell you if this patient is in the expected range for his age, height and gender.  If any of these initial values were low (FVC, FEV1, FEF25-75), you would probably administer albuterol and repeat this testing, looking for the magnitude of change in these values after albuterol.  

If any of this testing indicated active reactive airway disease or asthma, you would postpone allergy skin testing and either initiate asthma medication yourself, or refer for a pulmonary consultation. 

LEARNING CONTENT

What is anaphylaxis?  

Anaphylaxis is a severe generalized allergic reaction which can result in death if not treated promptly and appropriately.  It can occur during allergy skin testing or with allergy shots (SCIT, subcutaneous immunotherapy).   It ranges from a little itchiness  remote from the site of testing to cardiovascular collapse and death.  

How can anaphylaxis be prevented?

The best defense in this case is a good offense.  That means identifying the patients at higher risk for anaphylaxis, and planning their allergy evaluation with greater caution.  Studies of fatal and near fatal reactions show that two of the main factors associated with bad outcomes to anaphylaxis are breathing or asthma that is not well controlled, and failure to use epinephrine early.  (Epstein 2014)

 

Clues on history or physical exam that should prompt further consideration of breathing adequacy include:  (1) History of childhood asthma (2) exercise-induced  bronchospasm (3) any recent chest tightness, shortness of breath, wheezing or nocturnal awakenings with SOB or cough, (4) persistent cough, (5) exercise intolerance that seems out of proportion to estimated deconditioning.  If any of these are present, consider peak flow measurement, measurement of fractionated exhaled nitric oxide or spirometry for further deliniation of respiratory status prior to allergy skin testing.  

Other contraindications to allergy skin testing include pregnancy (because of a remote risk of hypoxic injury to the fetus should severe anaphylaxis occur), certain medications (see Unit on Medications and Allergy Skin testing) and comorbidities, such as severe coronary artery disease, that would make the chance of surviving severe anaphylaxis problematic.

Recognizing Anaphylaxis

Anaphylaxis starts small and subtly and builds.  If you train your staff to recognize the earliest signs of a systemic reaction (anaphylaxis), this enables early treatment and minimization of serious problems.

Here are the signs we watch for in our allergy practice:

  1. increased soft throat clearing or mild hoarseness- secondary to early laryngeal edema
  2. itchy skin distant from the site of testing
  3. facial or neck/chest flushing
  4. facial swelling

Other signs like frank urticaria, audible wheezing, confusion and hypotension occur later in the response-  hopefully you’ve caught and treated a reaction before it progresses to these.  

Treating Anaphylaxis

The most important rule of treating anaphylaxis it to administer intramuscular epinephrine early and as often as needed.

If someone is in advanced anaphylaxis when you first encounter them (which shouldn’t happen in your well-run office), the Trauma ABC assessment and treatment is used at the same time as the epinephrine injection, with airway support as needed.  Other than the epinephrine and perhaps antihistamines, this code situation is run as any other code.  

In the allergy office, the most common presentation is very early anaphylaxis.  If you just think there MIGHT be a beginning early anaphylaxis (systemic reaction), administer diphenhydramine or cetirazine in chewable tablet form for quickest absorption.  The diphenhydramine can also be administered intramuscularly.  Symptoms should begin to improve within 60 to 90 seconds.  If not, epinephrine is administered immediately.  Albuterol by MDI or nebulizer is administered if needed.  

If further treatment is required in the allergy office, oxygen is administered by face mask, and IV access is established.  Cardiovascular instability is treated using the ACLS guidelines.  Occasionally it is mentioned to put a tourniquet above the skin test site or to inject epinephrine around the skin test site to prevent further absorption of the allergen.  I have been unable to find any literature source examining whether these actions are helpful.  

Once the patient is stabilized, transport the patient to an Emergency Department for observation.  Biphasic anaphylaxis occurs in 10-20% of patients.  This later recurrence of symptoms can be milder, the same, or more severe.   There is unfortunately no way of predicting which patient will experience this.  Although ‘observation’ used to mean 24 hours in a clinical setting, recent literature reveals that 5-6 hours of observation is generally sufficient.  (Grunau et al 2014)

The well-run allergy office establishes an anaphylaxis protocol, and runs drills to assure that all personnel are familiar with their roles.  One person is designated as a record-keeper, recording vital signs, and the time, dose and route of all medications administered.  This information is handed on to transport personnel, with a copy kept for office charting.  It is important for the physician to document all the details of the reaction and care as soon as possible.

POST TEST

Q1:  True or False:  Epinephrine should only be administerd after all other medications, including antihistamines, leukotriene modifiers and intravenous steroids have failed.

A1:  As you know from reading the above unit, epinephrine early and as often as needed is the key to successful anaphylaxis treatment.

Q2:  The earliest signs of anaphylaxis include (chose one or more)

  1. Chills and shakes
  2. Hoarseness
  3. Total body urticaria
  4. Feeling of impending doom
  5. Facial flushing

A2:  B, E.  The mild hoarseness/throat clearing from early laryngeal edema is one of the first clues that a systemic reaction is occurring.  Facial flushing, lips tingling or tongue feeling clumsy are also early occurrences.  Total body urticaria happens much further on in the reaction. Chills and shakes and a feeling of impending doom may occur late in the reaction, or may be related to epinephrine administered.  

Q3:  Explain why most patients are not sent home directly from the office after epinephrine resolves anaphylaxis symptoms.

A3:  Even if there has been no cardiopulmonary instability, the patient who requires epinephrine is at risk for a biphasic anaphylaxis.  Five – six hours of clinical observation will identify the vast majority of these, allowing timely treatment.  

 

REFERENCES

Epstein TG, Liss GM, Murphy-Berendts K

, Bernstein DI.   AAAAI/ACAAI surveillance study of subcutaneous immunotherapy, years 2008-2012: an update on fatal and nonfatal systemic allergic reactions.  J Allergy Clin Immunol Pract. 2014 Mar-Apr;2(2):161-7.

Grunau BE, Li J, Yi TW, Stenstrom R, Grafstein E, Wiens MO, Schellenberg RR, Scheuermeyer FX.   Incidence of clinically important biphasic reactions in emergency department patients with allergic reactions or anaphylaxis.  Ann Emerg Med. 2014 Jun;63(6):736-44.

Lewis J.  BET 2: in children, do steroids prevent biphasic anaphylactic reactions?  Emerg Med J. 2014 Jun;31(6):510-2..

 

 

Otolaryngic Allergy Learning

Here’s your Go-To for learning about otolaryngic allergy.  The otolaryngologist brings a great viewpoint and useful knowledge to the delivery of allergy care.  We know the sinuses and nasal cavity intimately, and easily detect the appearance of pathologic findings.  We care for the nose and upper airway, understanding the surgical anatomy and physiology.  With the almost-mirror-image inflammation of the upper and lower airways, caring for the asthma of our allergic rhinitis patients allows us to coordinate these aspects of the patients care in a way that is convenient for the patient.

When I couldn’t find a textbook about otolaryngic allergy that was up-to-date and easy-to-use, I considered approaching publishers about writing such a text.  But then, I’d been  reading a number of books about the best ways for adults to learn- and realized that the traditional textbook was not a stronghold of these learning methods.  And the lead time on a textbook is so long-  2-3 years in most cases- that some of the information is out of date by the time the text reaches the reader.  And there may be newer important discoveries that are not included.  So, I decided to build a Learning Website that incorporated these newly-understood learning methods along with both the basic learning and the latest findings relevant to otolaryngic allergy.  I hope the website provides the learning tools you need!  Please let me know about other things you’d like to see included, or any topics or learning techniques that do/don’t work for you!

Karen H. Calhoun MD FACS FAAOA