Types of Adverse IV CONTRAST Reactions

ANAPHYLACTIC

Anaphylactic reactions are serious, potentially life-threatening reactions associated with the administration of contrast material. Acute bronchospasm, profound hypotension, and severe urticaria may occur within minutes of administration of as little as 1 mL of contrast material. These reactions are not “true” allergic reactions, because they can occur in patients who have not been exposed to contrast material previously. IgE antibodies, which are associated with allergic reactions, have not been demonstrated in most patients with anaphylactoid reactions.2 The etiology of these anaphylactic reactions is unclear.

DOSE DEPENDENT

Dose-dependent, systemic adverse reactions to contrast material include nausea and vomiting, a metallic taste in the mouth, and generalized warmth or flushing. These reactions are usually nonlife-threatening, self-limited problems.

Renal failure is another form of adverse reaction that is dependent on the dose of contrast material used. Intravenous administration of contrast material is responsible for 12 percent of cases of hospital-acquired renal failure.3 Renal failure following administration of contrast material occurs in 0.1 to 13 percent of patients who receive contrast material.4 This range results from the lack of a set definition for contrast-induced nephrotoxicity. A generally accepted definition is the elevation of serum creatinine to greater than 25 percent of baseline within three days of receiving contrast material. Proteinuria is often found on routine urinalysis but is not required for the diagnosis of contrast-induced nephropathy.

Patients with preexisting renal insufficiency and diabetes are at greatest risk of developing permanent renal failure following administration of contrast material. Patients with multiple myeloma are also at increased risk of developing renal failure, especially if they are dehydrated. The risk of renal failure in patients with myeloma is caused by an interaction of light chains and contrast material. How contrast materials cause renal failure is unclear, but direct cellular toxicity and intrarenal vasoconstriction are believed to be the primary causes of renal function changes.

DELAYED REACTIONS

Adverse reactions that occur 30 minutes or more after the administration of contrast material are considered delayed reactions. Delayed reactions are more common with the use of ionic agents.6 Up to 30 percent of patients receiving ionic contrast materials develop delayed reactions. Administration of nonionic agents is associated with delayed reactions in only 10 percent of patients. The symptoms of delayed reactions resemble a flu-like syndrome and include fever, chills, nausea, vomiting, abdominal pain, fatigue, and congestion.

EXTRAVASATION OF CONTRAST MATERIAL

Tissue damage from extravasation of contrast material is caused by the direct toxic effect of the agent. Compartment syndrome may occur if enough contrast material leaks into surrounding tissue.

Contrast-induced renal toxicity

Non-allergic, non-acute reactions to contrast media also occur. Another important reaction that concerns Cohan is that iodinated contrast material (used for IVPs, CTs and conventional angiography) is damaging to kidneys.

"We know that iodinated contrast material has the potential to damage kidney function," he says. "Such damage is exceedingly rare in people whose kidneys are working perfectly normally; however, it can be a problem in people who already have an element of kidney failure, such as acute renal failure or chronic kidney disease. Iodinated contrast media can make the kidneys function even more poorly in these people."

Many studies have attempted to look at this issue, but the results are conflicting.The greatest risk of contrast-media-induced renal toxicity seems to lie in patients who have renal failure and diabetes mellitus. It is less clear whether or not the presence of diabetes mellitus alone is a risk factor for contrast-induced renal toxicity.

"Some groups are believed to be at increased risk for developing renal toxicity from iodinated contrast material," says Cohan. "This includes people who have had several injections of contrast material over a short period of time – if there's more contrast material than their kidneys can handle, they may be more at risk for being damaged by that contrast material."

Also included are patients on other medications, such as some antibiotics and anti-inflammatory medication, that may damage the kidneys, and patients that have severe congestive heart failure or who are very dehydrated.

Side-effects from high osmolality / viscosity (fluid shifts from different compartments)contrast media

• • vasodilatation
  • heat
  • pain
  • osmotic diuresis
  • hemodynamic changes
• pharmacokinetics
  • distribute volume into extracellular space
  • clearance by glomerular filtration and renal excretion
• physiologic reaction
• increased plasma osmolality causes fluid shift from RBCs and pulmonary tissue leading to increased plasma volume
• then osmolar gradient reverses with passage of contrast bolus -> pulmonary capillary endothelium leaks protein into pulm interstitium --> increased pulmonary edema
• transient cardiovascular changes (magnitude increased with tonicity of medium)
  • increased PAP
  • increased CO with decreased peripheral/pulmonary vascular resistance
  • decreased systemic arterial pressure (variable)
• may activate gen receptors causing side effects

Conditions Associated with Adverse Reactions to Contrast Material

• Preexisting renal insufficiency
• Previous anaphylactoid reaction to contrast material
• Asthma
• Food or medication allergies, or hayfever
• Multiple medical problems or an underlying disease (e.g., cardiac disease, preexisting 
• azotemia)
• Treatment with nephrotoxic agents (e.g., aminoglycosides, nonsteroidal anti-inflammatory agents)