Intravenous contrast materials are widely used in a variety of imaging tests, such as MRIs, CTs and PET scans. Various types of contrast materials exist, differing in the size and type of molecules they contain. In general, the lighter materials are less likely to cause side effects, but their use can be limited by cost, as explained in a 2002 article on adverse reactions to contrast material in the journal American Family Physician. Side effects can be immediate or delayed, and can range from mild to life threatening.
Anaphylactic reactions usually begin within 20 minutes of receiving an intravenous injection of contrast material, as explained in a study published in Nuclear Medicine Technology. Mild symptoms include urticaria, which are itchy red welts, pruritus, meaning itching all over the body, nausea and vomiting. More serious symptoms include constriction of the airways and fluid in the airways and lungs. Disturbances in the heart rhythm may be life threatening. Seizures, closure of the airways and death may occur.
Contrast material can affect the autonomic nervous system, leading to a slow heart rate and dilation of blood vessels in the skin, which together can cause a dangerous drop in blood pressure. Nausea, vomiting, diffuse sweating and confusion are other symptoms. A feeling of warmth and a metallic taste may accompany the other symptoms. Untreated, low blood pressure can lead to circulatory collapse and death.
Reactions to contrast media can develop several days after the procedure. According to the American College of Radiology, they are relatively common. Symptoms are usually mild, consisting of weakness, upper respiratory flu-like symptoms, abdominal pain, nausea and vomiting. The most serious adverse reactions are skin lesions, which have the potential to be life threatening and require an examination by a dermatologist.
Kidney damage from intravenous contrast materials is especially likely to occur in patients who already have kidney disease. Acute renal failure is characterized by the kidneys shutting down, which means the body loses its ability to get rid of excess fluids and toxins and maintain the salt and acid base balance of the body. Since contrast material is excreted through the kidneys, caution should be used when administering it to people who have diminished kidney function. According to a study published in the Journal of Nuclear Medicine Technology, people with type 2 diabetes who take oral agents to manage their diabetes are at particular risk for contrast-induced renal failure.