1. Anaphylaxis in the Radiology Department
Anita Pozgay, MD, FRCPC Emergency Medicine,
Dip. Sport Med & Tropical Med.

2. Case One
A 7 year old comes in to the ED after an possible exposure to peanut butter
He has a severe nut allergy for which he was prescribed an EpiPen
He was recently admitted to PICU for a severe asthma attack but was not intubated
Mom gave him some oral Benadryl and he is no longer itchy but still has lip swelling

4. Case One continued
He is sent for a CXR due to decreased air entry in the lower lobes
While in radiology, he becomes acutely SOB and his lip becomes more swollen
What do you do now?

5. Case Two
A 45 y o woman involved in a MVC needs a CT abdo after she is stabilized in the ED
She received 2 L NS for a hypotensive episode and her BP is now 120/70
She has a positive FAST U/S
Although her CXR is normal she has palpable lower rib fractures & a distended abdomen

6. Case Two continued She is given both oral and IV contrast for her CT
She becomes hypotensive again!
What do you do now?
There is no rash

7. Case Three A 67 y o man is stung by an insect while gardening
He developed pruritus, dizziness, and SOB 20 min later so he called 911
He self-treated with Benadryl po and was given another 50 mg IV by EMS due to persistent sx and rash
He is now asymptomatic and refusing transport to hospital

8. Case Three: Do you transport?
EMS convinced him to get “checked out” in the hospital
On arrival, he becomes hypotensive, and his hives reappeared, along with facial edema
An ECG shows T wave inversion in his lateral leads
PHx: MI, HTN, IV contrast allergy
Meds: ASA, metoprolol, lisinopril

10. Case of EIA
28 year old male, after eating spaghetti and then playing soccer 1 hr later, developed urticaria & dizziness
attempted to drive to hospital but pulled over because worse
EMS vitals: BP 80/42, HR 90, RR 24
Rx: w/ epi and 1 litre NS
In ED: BP 130/85, chest was clear and “hives” gone but skin still edematous

11. Exercise Induced Anaphylaxis
Clinical features indistinguishable from allergen induced anaphylaxis
food dependent & food independent forms (also cholinergic urticaria)
mechanism not fully known, but thought exercise lowers threshold for mast cell degranulation esp after a food allergen triggers an IgE response

12. Exercise-Induced Allergic Syndromes

13. Natural History of EIA
N= 365 respondents with 10 yr hx of EIA to 75 item questionaire
EIA if anaphylactic Sx with exercise but not with passive warming
Shadick, Nancy A., et al. The Natural History of Exercise-Induced Anaphylaxis: Survey results from a 10-year follow-up study, J Allergy Clin Immunol 1999; 104:

14. Results of Survey frequency of attacks lesson over time
a wide range of activities associated but more CV demand more likely
70% had atopy or family hx of it
subjects avoided attacks by not exercising in humid weather or high allergy seasons
no single trigger identified; most common food
H1 blockers/ epi were used by 30% emergently; Role of prophylaxis?

15. Management Questions? What is the first line of therapy?
When do you give epi? Type? Route?
Do all patients need Epinephrine? Corticosteroids?
What is the role of combined H1 & H2 blockers?
Who needs to be monitored? Referred?
Who needs an EpiPen?

16. Epidemiology
Likely under reported due to lack of recognition or self treatment in the field
in Ontario: 4 cases/ 1 million
in Germany: 10 cases/
in Minnesota, U.S.A.: 17/19,122 visits
in Brisbane, Australia: 1/440 visits

17. Common Causative Agents
Drugs: Antibiotics, ASA, NSAIDS, sulfa, opioids, IV contrast dye
Foods: Peanuts, Seafood, Eggs, milk
Latex gloves
Insect Stings
Physical Factors: Exercise (FDEIA), Cold/Heat

18. Definitions
Anaphylaxis: “against protection”, a severe systemic allergic reaction in a previously sensitized person; must include respiratory difficulty or vascular collapse
* hives/angioedema NOT universally present!
Allergic reactions: localized urticaria, angioedema, contact dermatitis, rhinoconjunctivitis

19. Pathophysiology
Sensitization occurs when IgE adheres to the mast cell Ag (allergen)
IgE specific
Degranulation of mast cell
mediators

20. Anaphylactic vs. Anaphylactoid
Anaphylactoid has the same clinical features as anaphylaxis but is not IgE mediated
Instead it is due to direct mast cell degranulation and thus, does not require prior sensitization

21. SMOOTH MUSCLE CONTRACTION
Clinical Features
SMOOTH MUSCLE CONTRACTION
abdominal cramps
nausea
rhinitis
conjunctivitis
CAPILLARY LEAK
urticaria
angioedema
laryngeal edema
hypotension/syncope
MUCOSAL SECRETIONS
bronchospasm
diarrhoea
vomiting

22. Urticaria versus Angioedema
Both characterized by transient, pruritic, red wheals on raised serpiginous borders
urticaria due to edema of dermis
angioedema due to edema of subcutaneous tissues

31. DDx: Anaphylaxis MI/arrhythmia/cardiogenic shock
Airway obstruction due to other causes: FB aspiration, asthma, COPD, epiglottitis, peri-tonsillar abscess, etc.
Flushing syndromes (eg: carcinoid)
Vasovagal syncope
Panic attack
Scombroid poisoning
Hereditary angioedema

32. Management Questions? What is the first line of therapy?
When do you give IV vs IM epi?
Do all patients need Epinephrine; corticosteroids?
What is the role of combined H1 & H2 blockers?
Who needs to be monitored? Referred?
Who needs an EpiPen?

33. Key Management of Anaphylaxis
1st line of therapy:
AWARENESS
RECOGNITION
TREAT QUICKLY
CALL FOR BACK-UP!

35. Management: Adult Epi dosing
Epinephrine:
0.3 mg (0.3 ml) 1:1000 solution IM
(NOT SC or IV)
may repeat in 5 min X 1
(empirical only but safe)

36. Epi: Pediatric Dosing (0.01 ml/kg)
Age (yrs) Volume of Dose (mg)
1:1000(1mg/ml)
ml 0.1
ml 0.2
> ml 0.3

37. EPI cautions: Co-morbidities
Thyroid disease
Cocaine addicts
CAD on BBlockers, ACEi
Depression using MAOIs or TCAs
Bblockers blunt the response to epi and this is both B1 and B2. ACEi blunt the catecholamine response ( ACE/Nor-Epi/Epi rise) with shock.

38. Mechanisms of Epinephrine
Alpha agonist effects increase peripheral resistance, BP, reduce vascular leakage
Beta agonist effects cause bronchodilation, positive cardiac inotropy/chronotropy (caution in CAD pts!)

39. Dangers of Epinephrine IV
Only use IV Epi if patient has refractory shock not responding to fluid bolus first
dose 0.1 mg (10 ml) 1:100,000 dilution over 10 minutes
must be on cardiac monitor
caution in elderly or those with CAD
may cause supraventricular/ventricular dysrhythmias!

40. Management Do all patients need Epi?
Epinephrine reverses mediator release while antihistamines (H1) do not
Epinephrine should be used for all systemic signs of allergy: airway edema (includes tongue/lips), SOB, cyanosis, hypotension

41. Grading of Anaphylaxis
Grade
Skin
GI tract
Resp CV
Neuro 1
Local pruritus, hives, mild lip swelling
Oral “tingling”, pruritus 2
Generalized pruritus, hives, flushing, angioedema
Above plus nausea +/- emesis
Nasal congestion/
sneezing
Activity change 3
Any of above
Any of above + repetitive vomiting
Rhinorrhea, sensation of throat tightness
Tachy
( > 15 bpm)
Above plus anxiety 4
Any of above + diarrhea
Hoarseness
dysphagia, SOB, cyanosis
Above + arrhythmia +/- dec BP
dizziness
Feeling of impending doom 5
Any above + stool incont.
Any above + resp arrest
Brady +/- card arrest
LOC

42. Management: Do all patients need Corticosteroids?
Corticosteroids take 4-6 hours to work
theoretically blunt the multi-phasic reaction of anaphylaxis
the quicker the onset of anaphylaxis the worse the reaction/quicker resolution less likely to relapse
Caution in IV steroids esp if given in bolus doses; case reports of anaphylaxis!
Oral form preferred if possible

43. Histamine Classes
H1 receptor: stimulates bronchial, intestinal, smooth muscle contraction, vascular permeability, coronary artery spasm
H2 receptor: increase rate & force of ventricular & atrial contraction, gastric acid secretion, airway secretions, vascular permeability, bronchodilation, & inhibition of histamine release

44. Management: What is the role of combined H1 & H2 Antagonists?
RCT, N=91 w/ allergic syndromes
50 mg Benadryl (H1) & saline vs. 50 mg Benadryl & 50 mg Ranitidine (H2) IV
Endpoints of resolution of urticaria, angioedema, or erythema
also measured subjective improvement & vitals
Lin et al., Improved outcomes in patients with acute allergic syndromes who are treated with combined H1 & H2 antagonists, Annals of Emergency Medicine 36(5) 2000.

45. Histamines: Results
Statistically significant diminution of angioedema and/or urticaria with addition of H2 blocker
study too small to determine if H2 blockers helpful in anaphylaxis (those with respiratory compromise &/or hypotension)
also significant decrease in HR in Rx group

46. Back to Cases: Management Case 1

47. Case One: Peanut allergy in asthmatic
A 7 year old comes in to the ED after an possible exposure to peanut butter
He has a severe nut allergy for which he was prescribed an EpiPen
He was recently admitted to PICU for a severe asthma attack but was not intubated
Mom gave him some oral Benadryl and he is no longer itchy but still has lip swelling

48. Case One continued
He is sent for a CXR due to decreased air entry in the lower lobes
While in radiology, he becomes acutely SOB and his lip becomes more swollen
What do you do now?

49. Case 1 Conclusion He needs IM Epi!
(He weighs 30 kg and thus 0.3 mg IM is fine.)
O2, IV fluids, cardiac monitoring
Consider Ventolin neb (esp if concurrent asthma)

50. Case Two : MVC Management
A 45 y o woman involved in a MVC needs a CT abdo after she is stabilized in the ED
She received 2 L NS for a hypotensive episode and her BP is now 120/70, HR 100
She has a positive FAST U/S
Although her CXR is normal she has palpable lower rib fractures & a distended abdomen

51. Case Two continued She is given both oral and IV contrast for her CT
She becomes hypotensive again!
What do you do now?
There is no rash

52. Case 2: Conclusion
Is she in hypovolemic shock or anaphylactic? doesn’t matter b/c both require IV crystalloids!
There may be no rash initially
Look for airway compromise/swelling: intubate?
IV contrast reactions are anaphylactoid and so prior sensitization not necessary (thus may be no prior hx of anaphylaxis)
If no response to fluids give IV epi 1st via slow infusion, except if pulseless then may give IV bolus

54. Case 3: Gardener Management

55. Case Three A 67 y o man is stung by an insect while gardening
He developed pruritus, dizziness, and SOB 20 min later so he called 911
He self-treated with Benadryl po and was given another 50 mg IV by EMS due to persistent sx and rash
He is now asymptomatic and refusing transport to hospital

56. Case Three: Do you transport?
EMS convinced him to get “checked out” in the hospital
On arrival, he becomes hypotensive, and his hives reappeared, along with facial edema
An ECG shows T wave inversion in his lateral leads
PHx: MI, HTN, IV contrast allergy
Meds: ASA, metoprolol, lisinopril

57. Case 3 Management: Refractory Anaphylaxis
Biphasic (multi?) reactions can occur typically after 3-4 hours but as late as 72 hours later!
Beware of the patient with increased age and co-morbidities (eg. CAD) b/c anaphylaxis can cause cardiac ischemia
B-Blockers & ACEi blunt the catecholamine response

58. Management Refractory Anaphylaxis: Glucagon
Glucagon: increases inotropy/chronotropy & causes smooth muscle relaxation independent of B receptors
Dose: 1-5 mg in adults ( mg in kids) IV/IM

59. Management: Disposition & Follow-up
Inquire about possible antigen exposure
Those with systemic reactions require a prescription for and instruction on how to use a EpiPen
A Medic Alert Bracelet is useful
Follow-up with an allergist for skin testing should be arranged particularly if the allergen is unknown

60. EpiPen

61. Summary
Acute anaphylaxis is often poorly recognized & treated due to the protean clinical features and variation in the speed of onset
a trigger is often not found
Pruritis is a universal feature and should differentiate anaphylaxis from asthma
Expedious treatment w/ epi is necessary & thus patient education on its use is essential