ANAPHYLAXIS Flashcards
What is the most common trigger of anaphylaxis?
A. Exercise
B. Foods, drugs, or Hymenoptera stings
C. Pollen exposure
D. Cold weather
B. Foods, drugs, or Hymenoptera stings
Which of the following is NOT a common cutaneous manifestation of anaphylaxis?
A. Urticaria
B. Flushing with diffuse erythema
C. Petechial rash
D. Giant hives
C. Petechial rash
Which serum biomarker is most practical for diagnosing anaphylaxis?
A. Histamine
B. Prostaglandin D2
C. Serum tryptase
D. Platelet-activating factor (PAF)
C. Serum tryptase
- more practical and useful biomarker is serum tryptase, which peaks 60–90 min after the onset of anaphylaxis and can be measured as long as 5 h after the onset
What is the first-line treatment for anaphylaxis?
A. Intravenous fluids
B. Intramuscular epinephrine
C. Antihistamines
D. Corticosteroids
B. Intramuscular epinephrine
- The treatment of first choice is intramuscular administration of 0.3–0.5 mL of 1:1000 (1 mg/mL) epinephrine, with repeated doses at 5- to 20-min intervals as needed for a severe reaction.
TRUE OR FALSE: Failure to use epinephrine within the first 20 min of symptoms is a risk factor for poor clinical outcomes
TRUE
How long after the onset of anaphylaxis can serum tryptase levels still be measured?
A. <1 hour
B. 2–3 hours
C. 5 hours
D. 24 hours
C. 5 hours
serum tryptase, which peaks 60–90 min after the onset of anaphylaxis and can be measured as long as 5 h after the onset
What is a key feature of the “empty ventricle syndrome” in anaphylaxis?
A. Sudden-onset tachycardia
B. Insufficient venous return to the heart
C. High cardiac output
D. Delayed response to epinephrine
B. Insufficient venous return to the heart
- Upright or sitting posture may lead to “empty ventricle syndrome”
- insufficient venous return to the heart from sudden-onset hypotension secondary to intravascular volume depletion
- recommended that patients who suffer from anaphylaxis be placed in the supine position before receiving epinephrine
Which statement about epinephrine in anaphylaxis is TRUE?
A. It provides only β-adrenergic effects.
B. It is contraindicated in patients with hypertension.
C. It should be given intramuscularly in doses of 0.3–0.5 mL of 1:1000 concentration.
D. Beta blockers enhance its effect.
C. It should be given intramuscularly in doses of 0.3–0.5 mL of 1:1000 concentration.
Which food allergy is most likely to persist into adulthood?
A. Milk
B. Soy
C. Wheat
D. Peanut
D. Peanut
What is the purpose of desensitization in the management of anaphylaxis?
A. To prevent anaphylaxis permanently
B. To induce temporary tolerance to a specific allergen
C. To eliminate IgE from the bloodstream
D. To treat acute symptoms
B. To induce temporary tolerance to a specific allergen
- Desensitization elicits a temporary state of tolerance to the drug in sensitized, clinically reactive patients
- effective for certain chemotherapy agents, especially platin-based chemotherapy agents that can induce IgE-mediated sensitization with repeated exposures
Which drug may blunt the efficacy of epinephrine in anaphylaxis?
A. Beta-blockers
B. Alpha-blockers
C. ACE inhibitors
D. Calcium channel blockers
A. Beta-blockers
- Epinephrine provides both α- and β-adrenergic effects, resulting in vasoconstriction, bronchial smooth-muscle relaxation, and attenuation of enhanced venular permeability
- Beta blockers may attenuate this response
- therefore, an alternative antihypertensive may be considered in patients at high risk of needing emergency epinephrine
What is the primary role of prostaglandin D2 in anaphylaxis?
A. Causes severe hypotension
B. Attracts eosinophils and basophils to the site of activation
C. Induces smooth muscle relaxation in the bronchi
D. Suppresses cutaneous symptoms
B. Attracts eosinophils and basophils to the site of activation
- Prostaglandin D2 causes cutaneous flushing and attracts eosinophils and basophils to the site of mast cell activation
Which arachidonic acid-derived product is primarily responsible for bronchoconstriction in anaphylaxis?
A. Platelet-activating factor (PAF)
B. Prostaglandin D2
C. Cysteinyl leukotrienes
D. Histamine
C. Cysteinyl leukotrienes
- Cysteinyl leukotrienes and prostaglandin D2 cause bronchoconstriction and increased microvascular permeability
Which condition is associated with atopy as a predisposing factor for anaphylaxis?
A. Hymenoptera sting allergy
B. Drug-induced anaphylaxis
C. Idiopathic anaphylaxis
D. Chemotherapy-induced IgE sensitization
C. Idiopathic anaphylaxis
- Atopy is not generally thought to be a risk factor for anaphylaxis from drug reactions or Hymenoptera stings, but it is associated with radiocontrast sensitivity, exercise-induced anaphylaxis, idiopathic anaphylaxis, and allergy to foods or latex
- IgE-mediated drug allergies are most common with antibiotics and certain chemotherapy drugs
What percentage of anaphylactic episodes are biphasic, with symptoms recurring after initial resolution?
A) 1–5%
B) 10–20%
C) 30–40%
D) 50–60%
Correct Answer: B) 10–20%
Rationale: The majority of anaphylactic episodes (80–90%) are uniphasic. However, approximately 10–20% of cases are biphasic, meaning symptoms recur after an initial resolution, typically after an hour or more.
Which of the following mediators is responsible for bronchoconstriction and increased microvascular permeability in anaphylaxis?
A) Histamine and serotonin
B) Cysteinyl leukotrienes and prostaglandin D2
C) Bradykinin and nitric oxide
D) Platelet-activating factor and thromboxane A2
Correct Answer: B) Cysteinyl leukotrienes and prostaglandin D2
Rationale: Cysteinyl leukotrienes (LTC4, LTD4, LTE4) and prostaglandin D2 (PGD2) contribute to bronchoconstriction and increased microvascular permeability, which are key pathophysiological mechanisms in anaphylaxis.
Which of the following best describes the relationship between platelet-activating factor (PAF) and anaphylaxis severity?
A) PAF levels are directly proportional to the level of PAF acetylhydrolase
B) PAF levels are inversely proportional to PAF acetylhydrolase activity
C) PAF levels remain unchanged during anaphylaxis
D) PAF acetylhydrolase is not involved in anaphylaxis regulation
Correct Answer: B) PAF levels are inversely proportional to PAF acetylhydrolase activity
Rationale: Serum PAF levels correlate with anaphylaxis severity, and their levels are inversely proportional to the activity of PAF acetylhydrolase, an enzyme that inactivates PAF. Lower levels of PAF acetylhydrolase result in higher PAF levels and more severe anaphylaxis.
