Non-ionic IV contrast may be safely administered in these patients based on Bessell-Browne et al, CT of Pheochromocytoma and Paraganglioma: Risk of adverse events with IV administration of non-ionic contrast material, AJR 2007; 188: 970-974 and the ACR manual. No follow-up blood pressure monitoring is needed. Direct injection of contrast medium into the adrenal or renal artery is to be avoided however, as this may cause a hypertensive crisis.
Patients with allergies have twice the risk of contrast reactions compared to the average patient.
Patients with asthma have five times the risk of contrast reactions compared to the average patient.
IL-2 (Interleukin – 2 Chemotherapy)
Patients who are currently on IL-2, or have received IL-2 in the recent past, have an increased risk of delayed reaction. The reaction can occur up to several hours after the injection, and can be mild to severe. Symptoms can include hives, rash, pruritis, fever, chills, joint pain, flu-like symptoms, tachycardia, or hypotension. Symptoms can be mild and self-limited, or severe requiring hospitalization. Patients who have experienced an IV contrast reaction while on IL-2, or after IL-2 therapy should not receive IV contrast for any future imaging unless an extreme situation arises. (IL-2 patients should NOT receive steroid pre-medication. That counteracts the intended effect of IL-2).
Patients receiving IV contrast who are currently on IL-2 therapy or for 6 months following the completion of IL-2 therapy must be monitored for a minimum of two hours after their CT scan. This is usually done in the oncology clinic or in our waiting room after the scan. Six months after the cessation of therapy or after 2 uneventful contrast-enhanced scans the patient may return to normal monitoring.
Diabetes, Renal Failure, Nephrectomy, Renal Transplant
Metformin is an oral antihyperglycemic medication administered alone or in combination (see a list of metformin containing medications). There have been case reports of patients developing lactic acidosis after receiving iodinated contrast material while on metformin. Therefore, if a patient is on metformin, or a metformin containing medication, determine which of the two following categories describes the patient’s situation:
- No evidence of acute kidney injury and an eGFR ≥ 30. In this setting, metformin can be continued and there is no need to reassess renal function.
- Acute kidney injury or severe chronic kidney disease (stage IV or stave V, eGFR <30) OR arterial catheter studies that might result in emboli to the renal arteries. In this setting, metformin should be held 48 hours after the contrast bolus/procedure. Renal function should be reassessed 48 hours after the contrast load; if renal function is normal (or at baseline), metformin may be restarted.
A disease that causes hyperuricemia. The patient needs to have a normal creatinine level and not be dehydrated prior to receiving IV contrast, to reduce the risk of acute renal failure. (note: patients with only a history of gout but not active are not considered at risk)
A malignant bone condition that causes kidney failure, dysproteinemia, abnormal proteins in the plasma, and abnormal urine proteins (Bence Jones proteins). IV contrast may cause the proteins to precipitate resulting in renal tubular obstruction and possibly renal failure. Multiple myeloma is only considered a risk factor for contrast nephrotoxicity when combined with pre-existing renal insufficiency.
Creatinine level must be known prior to IV contrast administration. Please reinforce the importance of hydration after contrast administration.