CIR Contrast Media Administration & Adverse Reaction Management 2 — Questions and Answers
Question 1: According to ACR classification, which clinical presentation defines a SEVERE anaphylactoid contrast reaction?
- Urticaria covering less than 50% of body surface area
- Nausea and vomiting lasting more than 30 minutes
- Bronchospasm, laryngeal edema, or cardiovascular collapse (Correct answer)
- Isolated systolic blood pressure drop of 10 mmHg
Correct answer: Bronchospasm, laryngeal edema, or cardiovascular collapse
Severe anaphylactoid reactions are defined by life-threatening airway compromise (bronchospasm, laryngeal edema) or cardiovascular collapse requiring immediate resuscitative intervention.
Question 2: What is the FIRST-LINE treatment for a severe anaphylactic reaction occurring during cardiac catheterization?
- IV diphenhydramine 50 mg
- IV hydrocortisone 200 mg
- IM epinephrine 0.3–0.5 mg (1:1000) (Correct answer)
- IV atropine 1 mg
Correct answer: IM epinephrine 0.3–0.5 mg (1:1000)
Intramuscular epinephrine (1:1000) in the anterolateral thigh is the gold standard first-line treatment for anaphylaxis due to its rapid alpha and beta-adrenergic effects.
Question 3: A patient develops diffuse urticaria and mild itching 5 minutes after contrast injection with no respiratory or hemodynamic changes. How is this classified?
- Severe anaphylactoid reaction
- Mild anaphylactoid reaction (Correct answer)
- Delayed T-cell-mediated hypersensitivity
- Vasovagal reaction
Correct answer: Mild anaphylactoid reaction
Cutaneous symptoms (urticaria, pruritus) without airway involvement or hemodynamic compromise are classified as a mild anaphylactoid reaction under ACR guidelines.
Question 4: During contrast injection, a patient develops bradycardia to 38 bpm, diaphoresis, and hypotension without urticaria or bronchospasm. What is the MOST likely reaction type?
- Severe anaphylaxis
- Moderate anaphylactoid reaction
- Vasovagal reaction (Correct answer)
- Contrast-induced cardiomyopathy
Correct answer: Vasovagal reaction
Bradycardia with diaphoresis and hypotension in the absence of cutaneous or respiratory symptoms is characteristic of a vasovagal reaction triggered by pain, anxiety, or vagal stimulation.
Question 5: What is the appropriate treatment for a vasovagal reaction with persistent bradycardia and hypotension during a catheterization procedure?
- Epinephrine IV push and antihistamine
- Atropine IV and IV fluid bolus (Correct answer)
- Diphenhydramine IV alone
- Methylprednisolone IV infusion
Correct answer: Atropine IV and IV fluid bolus
Vasovagal reactions are treated with atropine to reverse vagally-mediated bradycardia and IV fluids to restore preload and blood pressure.
Question 6: Which patient factor is the STRONGEST predictor of a repeat adverse contrast reaction?
- Age over 70 years
- Documented seafood allergy
- History of a prior moderate or severe contrast reaction (Correct answer)
- Asthma without prior contrast exposure
Correct answer: History of a prior moderate or severe contrast reaction
A prior moderate or severe reaction to iodinated contrast media is the strongest risk factor for recurrence, with repeat reaction rates significantly higher than in the general population.
Question 7: Which ACR-recommended premedication regimen is used for ELECTIVE contrast studies in patients with a prior contrast reaction?
- Single-dose IV methylprednisolone 1 hour before contrast
- Prednisone 50 mg PO at 13, 7, and 1 hour before contrast plus diphenhydramine 50 mg PO 1 hour before (Correct answer)
- Diphenhydramine 25 mg PO only, 1 hour before
- Ranitidine 150 mg PO the night before only
Correct answer: Prednisone 50 mg PO at 13, 7, and 1 hour before contrast plus diphenhydramine 50 mg PO 1 hour before
The ACR elective premedication protocol is prednisone 50 mg PO at 13, 7, and 1 hour before contrast plus diphenhydramine 50 mg PO 1 hour before to reduce reaction risk.
CIR Contrast Media Administration & Adverse Reaction Management 2
According to ACR classification, which clinical presentation defines a SEVERE anaphylactoid contrast reaction?