X-ray examination of the GIT 4 Flashcards
What are anaphylactoid contrast reactions, and what is unique about their occurrence?
- Definition: Acute, dose-independent reactions that mimic allergic responses.
What are the risk factors that increase susceptibility to anaphylactoid reactions?
• Allergic asthma.
• Drug and food allergies.
• Cardiopulmonary conditions.
• History of prior reactions to contrast media.
How can anaphylactoid reactions be prevented?
- Use non-ionic contrast media, which have a lower incidence of reactions.
- Administer premedication such as 32 mg methylprednisolone orally, 6–12 and 2 hours before contrast administration.
- Create a calm and anxiety-free environment for the patient during the examination.
What are chemotoxic reactions to contrast media, and what causes them?
• Definition: Dose-dependent side effects caused by the concentration and volume of the contrast media.
• Categories:
1. Chemotoxic effects: Pain, heat sensation, circulatory disturbances, renal impairment.
2. Vasovagal reactions: Hypotension and bradycardia.
• Causes: Osmolality and pharmacological properties of the contrast media.
What are some strategies to prevent iodine-based contrast media reactions?
- Consider alternative diagnostic tests like ultrasonography or MRI that do not require iodinated contrast media.
- Use appropriate contrast media and premedication if contrast is essential.
- Monitor patients in the radiology department for at least 30 minutes post-injection and for up to an hour for high-risk patients.
What is the role of radiographers in the treatment of iodine contrast media reactions?
• Early recognition and accurate assessment of reactions.
• Ensuring critical medications and equipment are readily available.
• Administering medications like bronchodilators, antihistamines, and epinephrine as needed.
How does albuterol/salbutamol help in managing contrast reactions?
• It is a bronchodilator that relieves bronchospasm, which may occur due to asthma or a reaction to contrast media.
What is the role of atropine in managing contrast reactions?
• A parasympatholytic agent used to treat bradycardia caused by vasovagal reactions, which are characterized by hypotension and bradycardia.
When is diphenhydramine used during contrast media reactions, and what does it do?
• Used to treat mild urticaria.
• It is an H-1 receptor blocker that provides symptomatic relief and helps prevent further reactions.
What are the uses and cautions of epinephrine in severe contrast media reactions?
• Uses:
o Peripheral vasoconstriction for severe urticaria, facial, and laryngeal edema.
o Bronchodilation for bronchospasm.
o Enhancing cardiac contractility and heart rate.
• Caution: Use carefully in patients with cardiac disease or hypertension.
How does clonidine assist in managing reactions to contrast media?
• It is used to treat hypertensive crises resulting from reactions to contrast media.
What essential guidelines should radiographers follow after contrast media administration?
- Ensure patients remain under observation for at least 30 minutes post-injection.
- High-risk patients should be monitored for the first hour.
- Create a calm and reassuring environment to minimize anxiety-related side effects.
What are the unique features of anaphylactoid contrast reactions,
- They can occur even the first time contrast media is administered.
- Severity is not dose-related, so test doses are ineffective.
- A prior reaction does not guarantee recurrence, but the risk is higher
