Contrast agents: reactions: practice question

A Radiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Radiology · Contrast agents: reactions

Sample item

Three minutes after intravenous iodinated contrast, a patient develops generalised urticaria, stridor, wheeze and a blood pressure of 70/40 mmHg. What is the first-line treatment?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Intramuscular adrenaline, with oxygen, airway support and intravenous fluids

A severe anaphylactoid reaction to iodinated contrast presents with airway and circulatory compromise, and adrenaline is the first-line treatment, given intramuscularly (0.5 mg of 1:1000 in an adult) and repeated as needed. Oxygen, rapid fluid and airway support follow. Steroids and antihistamines are adjuncts. A prior reaction is the strongest risk factor, and steroid premedication may be considered for future studies.

Option by option

  • A. Intramuscular adrenaline, with oxygen, airway support and intravenous fluids (correct)

    Correct. Adrenaline is life-saving and should not be delayed.

  • B. Inhaled salbutamol alone

    Salbutamol does not treat hypotension and laryngeal oedema.

  • C. Oral antihistamine and observation

    An oral antihistamine is inadequate for a life-threatening reaction.

  • D. Intravenous hydrocortisone alone

    Steroids take hours to work and do not treat the shock.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Radiology question

What is the answer to this Radiology question?

The best answer is A, Intramuscular adrenaline, with oxygen, airway support and intravenous fluids. A severe anaphylactoid reaction to iodinated contrast presents with airway and circulatory compromise, and adrenaline is the first-line treatment, given intramuscularly (0.

Why is "Inhaled salbutamol alone" not the answer?

Salbutamol does not treat hypotension and laryngeal oedema.

Why is "Oral antihistamine and observation" not the answer?

An oral antihistamine is inadequate for a life-threatening reaction.

Why is "Intravenous hydrocortisone alone" not the answer?

Steroids take hours to work and do not treat the shock.

What concept does this question test?

It tests Contrast agents: reactions in Radiology. 5 mg of 1:1000 in an adult) and repeated as needed. Oxygen, rapid fluid and airway support follow. Steroids and antihistamines are adjuncts. A prior reaction is the strongest risk factor, and steroid premedication may be considered for future studies.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Contrast agents: reactions?

Learn signs with the image, and the disease they point to. Then use the flashcards and the other Radiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.