Anaphylaxis Flashcards
Anaphylaxis is what type of allergic reaction
Type 1, IgE-triggered
Anaphylactoid reactions are what type of allergic reaction
Type 1; non-IgE-triggered
Describe the physiology of anaphylaxis
- exposure to antigen causes IgE antibodies to bind to surface of mast cells & basophils
- repeat exposure to antigen causes binding to IgE antibodies
- degranulation of mast cells and basophils
- release of inflammatory mediators
Most important inflammatory mediators in an anaphylactic rxn
- histamine
- leukotriene
- prostaglandin
- tryptase
Key difference between anaphylactic & anaphylactoid rxns
anaphylactoid rxn = can occur on 1st exposure, does not depend on IgE antibodies to produce response
4 body systems affected in anaphylaxis
1) cutaneous (pruritis, flushing, angioedema)
2) resp (wheezing, SOB, increased airway pressures)
3) GI (N/V/D, abd pain, incontinence)
4) CV (HoTN, tachy, arrhythmias, shock)
What causes the vasodilation & increased capillary permeability associated with anaphylaxis?
histamine: H1 and H2 receptors –> HoTN
S/S in anesthetized patients experiencing anaphylaxis (triad)
- cutaneous signs
- CV collapse (HoTN)
- bronchospasm/increased PIP/hypoxemia
Most common cause of perioperative anaphylaxis in Europe?
NMBAs
Most common cause of perioperative anaphylaxis in US?
antibiotics (B lactams: PCN & cephalosporins)
Highest to lowest NMBA anaphylaxis sensitivity
Succs > Roc > Cis/Atra > Pan > Vec
An anaphylactic rxn occurring 30-60min after incision is likely d/t…
latex
Risk factors for perioperative anaphylaxis
- hx of a previous rxn
- female
- food allergies
- seasonal allergies
- multiple sxs
- elderly w/ COPD/CAD
Goals of treating anaphylaxis:
1) stop administration of allergen
2) abate effects of toxic mediator release
3) prevent further mast cell degradation
T/F: Epi dose in anaphylaxis depends on severity
true
Grade 1 anaphylaxis symptoms and Epi dose
cutaneous signs only (erythema, urticaria, angioedema)
NO Epi
Grade 2 anaphylaxis symptoms and Epi dose
cutaneous signs, HoTN, tachycardia, wheezing, difficult ventilation, N/V/D, abd pain
10-20mcg boluses
Grade 3 anaphylaxis symptoms and Epi dose
life-threatening severity; CV collapse, profound HoTN, bradycardia, arrhythmias, bronchospasm, hypoxia, N/V/D, incontinence
100-200mcg boluses, +/- infusion
Grade 4 anaphylaxis symptoms and Epi dose
cardiac/resp arrest
1mg + infusion @ 0.05-1.0 mcg/min
2 most critical interventions for treating anaphylaxis:
1) IV fluids
2) Epi
Effect of Epi on anaphylaxis processes:
- A1: vasoconstriction, decreased permeability
- B1: inotropy, chronotropy
- B2: bronchodilation
- inhibits mast cell degradation & release of mediators
Medication options for anaphylaxis refractory to Epi
- vasopressin
- Dopamine, NE, Isuprel
- Glucagon
- Methylene blue
- bronchodilators
- antihistamines
- corticosteroids (prevents late response)
T/F: The order of medications administered is often predictive of the causative factor of anaphylaxis.
False
T/F: Any med administered during the perioperative period can cause anaphylaxis.
True
