2 Contrast agent allergies, hazards, its therapy

Question 1

Oral X-ray contrast media side effects

Answer 1

Insoluble medias, barium sulfate cause severe inflammation if the leak out of the GI tract.

Ionic contrast media are hypoerosmolar and have bad kidney side effects, so they are used orally/rectally.
BUT since they are hyperosmolar they cause water excretion into the GI and can cause diarrhea and dehydration.

Question 2

IV X-ray contrast agent side effects side effects

Answer 2

1) Extravasation of the agent at the site of injections
- small amounts mild local pain
- large amounts can cause Necrosis or Compartment Syndrome, both of which will need surgery.

2) Allergic reaction, potential anaphylaxis

3) Renal toxicity, especially if the patient is dehydrated, GFR should be over 60 ideally. If GFR is between 30-60, you cannot use hyperosmolar agents. GFR 30 or below, idodinated agents are contraindicated and you should choose another imaging method.
Metformin and other kidney excreting drugs need to be stopped the day before IV contrast study, and not restarted until 2 days after.

3) Nausea, vomitting
4) Transient Hyperthyroidism 3-5 days after idodinated contrast administration

5)

Question 3

Contraindications for IV iodinated contrast agents

Answer 3

GFR below 60, relative, below 30 absolute.

Thyrotoxicosis

During pregnancy contraindicated unless it is an absolute requirement and an emergency.
Baby should be checked for thyroid funtion for possible contrast induced hyperthyroidism.

Question 4

MRI contrast agent side effects

Answer 4

Gadolinium agents are relatively safe, safer than iodine.

Still some potential for anaphylaxis.

Has a very rare but serious side effect nephrogenic systemic fibrosis. Fibrosis of the skin, joints, eyes, and organs.