Dr. Hesley is an Assistant Professor of Radiology, and Dr. Hartman is an Assistant Professor of Radiology, Mayo Clinic College of Medicine, Rochester, MN.
Fewer than 10 years ago, the authors decided which patients should
receive ionic versus nonionic contrast agents based on the patient’s
age, medical histories, known allergies, and the examination being
performed. Since the price of nonionic, low-osmolar agents has
decreased, these agents are now used nearly universally for intravenous
(IV) contrast administration. While the advent of nonionic, low-osmolar
contrast agents has led to a decrease in the frequency of adverse
contrast reactions, reactions from both iodinated agents and gadolinium
agents still do occur. In addition, patients with iodinated reactions
are known to be 2.3 to 3.7 times more likely to have a reaction to
gadolinium.1,2 These events can range in severity from hives
to cardiovascular shock. Screening patients prior to the administration
of contrast as well as preparation to immediately evaluate and treat
these reactions is important in providing good-quality patient care.
Prevention of reactions
most effective management of contrast reactions is to prevent them
from occurring. While contrast reactions are idiosyncratic, it is
important to have a good screening program in place to decrease the
number of patients who might have a reaction. In our practice, nursing
personnel interview the patients about any history of reactive airways
disease, cardiac problems, previous IV contrast media administration,
any associated contrast reactions, and any allergic reactions to
medications or other allergens. We also obtain a complete list of their
current medications. Due to the nephrotoxic nature of iodinated contrast
agents and the recent implication of gadolinium in the development of
nephrogenic systemic ﬁbrosis, patients are also asked if they have a
history of renal problems or if they are diabetic.
have a history of prior anaphylactoid contrast reaction are usually
premedicated before any contrast administration. Premedication
algorithms, including those recommended by Lasser and Greenberger, can
be utilized.3–7 Both premedication regimens use steroids to
help stabilize the cell membranes of basophils and mast cells to preempt
the release of potent vasodilators. Diphenhydramine and, in some cases,
ephedrine are included in the Greenberger protocol.6,7 Alternative
tests that do not require contrast administration should also be
considered for patients with prior moderate-to-severe reactions. It is
important to note that the acute treatment of contrast reactions does
not include the administration of corticosteroids. However, the
administration of 200 to 300 mg of hydrocortisone can be helpful in the
prevention of rebound reactions following the initial treatment of a
Treatment of reactions
Being prepared for
a reaction requires access to the proper medications and equipment for
the treatment of common reactions following contrast administration.
Stocking a small medication box with commonly used medications is
recommended (Figure 1). Such a box should include oral and IV
diphenhydramine, epinephrine in the subcutaneous (SQ) 1:1000 and IV
1:10,000 dilutions, atropine, nitroglycerin, 50% dextrose solution,
furosemide, B-agonist inhaler, and corticosteroids. This preparation
prevents unwanted delays that might occur if someone had to sort through
a larger emergency cart used predominantly for the treatment of cardiac
arrest situations. Having these medications (as well as a copy of the
American College of Radiology’s contrast media guide or your
institution’s guidelines for treatment of reactions) readily available
where contrast is being administered is helpful in ensuring that the
correct medications in the proper dosages are administered. This is
particularly important since contrast reactions are infrequent
occurrences and dosages may not be readily remembered. In addition to
the proper medications, it is also important to have a variety of airway
devices (including bag valve mask devices for patients of all sizes and
ages, nasal cannulas, oral airway kits, suction devices, and an oxygen
source) to provide proper early care in the treatment of many reactions
(Figure 2). Access to an automated external deﬁbrillator or other
deﬁbrillator is also recommended in the event of cardiovascular shock.
the Mayo Clinic in Rochester, MN, >90,000 doses of IV contrast are
typically administered each year and more than one third of the contrast
reactions are caused by the administration of gadolinium. The most
common contrast reaction is hives, which typically present as raised red
wheels that may or may not be associated with pruritus. When hives are
mild, they can simply be observed. However, patients who are more
symptomatic may require oral (PO) or IV diphenhydramine at a dose of 25
to 50 mg. Diphenhydramine is an antihistamine that has both
anticholinergic and sedative effects.
Other, less common skin
type reactions include angioedema and diffuse erythema. Angioedema
results in localized swelling and erythema of the face around the eyes
and mouth. Patients with diffuse erythema often have orthostatic
hypotension and a bright red appearance. These patients are treated with
oxygen administered by mask, isotonic IV ﬂuids, and either 50 mg
diphenhydramine or 0.1 mg epinephrine SQ (1:1000 dilution). If the
patient is hypotensive or has a compromised airway, administering 0.1 mg
epinephrine in the IVform (1:10,000 dilution) is recommended.
Epinephrine acts on both the alpha and beta receptors of the sympathetic
system and results in the relaxation of the smooth muscles of the
bronchi and causes an increase in blood ﬂow and cardiac output.
Intravenous administration of medications is necessary in the
hypotensive patient because medications given subcutaneously will not be
mobilized into the intravascular system in these patients.
most common reaction involving the airway is bronchospasm, during which
patients often develop tachycardia and dypsnea. These patients often
have a history of reactive airway disease. On auscultation, they usually
have expiratory wheezing or both inspiratory and expiratory wheezing.
Treatment that consists of 2 puffs from a beta-agonist inhaler, oxygen
by mask, and isotonic IV ﬂuids is often effective. If a patient’s
symptoms progress and he/she is hypotensive, 0.1 mg IV epinephrine
(1:10,000) should be administered.
Other airway-related reactions
include laryngeal edema and pulmonary edema. Patients who develop
laryngeal edema often have difficulty speaking and swallowing. They have
inspiratory stridor due to their narrowed airways, and they require
treatment with oxygen, isotonic IV ﬂuids, and 0.1 mg IV epinephrine
(1:10,000). In contrast, patients with pulmonary edema are tachypneic,
tachycardic, and diaphoretic. On auscultation, rales are present in the
bases. Treatment of pulmonary edema involves the administration of
oxygen by mask and isotonic IV ﬂuids, and furosemide 10 to 40 mg IV is
recommended. Furosemide works as a potent diuretic.
related to the vascular system predominantly include vasovagal
reactions, cardiovascular shock, hypertensive crises, angina, and
seizures. Vasovagal reactions and cardiovascular shock reactions both
present with hypotension. These events are distinguished from each
another in that vasovagal patients will be bradycardic and patients in
shock will be tachycardic. Vasovagal reactions are often related to the
needle puncture for IV placement or occur in the percutaneous biopsy
procedures. As previously stated, these patients are hypotensive and
bradycardic. They are usually pale and have a decreased level of
consciousness. Treatment often requires only the elevation of the
patient’s feet and/or the administration of IV ﬂuids. Occasionally, 0.5
mg atropine will be needed. Atropine has anticholinergic effects, and
tachycardia occurs because of the paralysis of vagal control.
Cardiovascular shock patients, on the other hand, are hypotensive and
tachycardic. These patients require oxygen, isotonic IV ﬂuids, and 0.1
mg IV epinephrine (1:10,000).
Hypertensive crisis is an extremely
rare reaction in which the patient’s diastolic blood pressure is
>120 mm Hg. Patients have throbbing headaches and may be confused or
nauseated. Treatment with nitroglycerin, either in the sublingual tablet
form (0.4 mg) or topical 2% form (1/2 inch strip applied to a 1 × 3
inch area), is often effective. Furosemide may also be used in these
patients. Nitroglycerin acts by relaxing vascular smooth muscle to
decrease the blood pressure. Nitroglycerin can also be used in patients
who develop angina related to contrast administration. These patients
are treated with oxygen, IV ﬂuids, and nitroglycerin. Finally,
occasionally seizures can occur. These are typically due to hypotension
and are often self-limited. In most cases, patients require observation
and supportive therapy only. Maintaining the patient’s airway, and
administering oxygen and IV ﬂuids will often sufﬁce. If seizures
persist, it can be helpful to administer a benzodiazepine such as 2 to 4
mg IV lorazepam, 5 mg IV diazepam, or 2.5 mg IV midazolam. These drugs
work to depress the central nervous system.
A few additional
situations may be encountered with the administration of contrast.
Patients will occasionally develop uncontrolled shaking known as rigors.
These are often self-limiting. If they persist, 25 to 50 mg meperidine
has been found to be effective. The mechanism in the development of
rigors as well as the reason for the effectiveness of meperidine is
uncertain. As patients often have multiple tests scheduled for the same
day and have been without food for many hours, patients may experience a
hypoglycemic episode during which they feel weak, dizzy, or faint.
Patients usually require only a glass of juice to relieve their
symptoms. On occasion, a 15-g glucose tablet or the administration of a
50% dextrose solution will be needed. When giving IV ﬂuids to these
patients, a 5% dextrose in water solution is recommended.
It is important to remember that
pediatric patients may also have contrast reactions but may be unable to
communicate their symptoms. It is a good idea to undress the infant to
fully determine the extent of a skin reaction. Having a treatment card
with the proper dosages listed for each of the common drugs used in
cases of reaction and knowing the patient’s weight are helpful to
quickly treat these uncommon reactions.
Extravasation of contrast into the soft tissues has been reported to occur in 0.3% to 0.6% of contrast administrations.8-11 Most
extravasations in our practice involve small volumes (<50 mL).
Extravasations are treated with the use of elevation of the extremity
above the level of the heart and the addition of either cold or warm
packs over the site every 2 hours for up to 12 hours if needed. The site
must be monitored for the development of altered sensation or
perfusion, ulceration, or blistering as well as for increasing redness,
swelling, or pain. For large-volume extravasations (>100 mL),
consultation with a plastic surgeon is usually requested.
All instances of contrast reactions or
extravasations and the subsequent treatment administered must be
documented. It is helpful to record the information in patients’ medical
records and alert their physicians to any contrast reaction. With this
information, the physicians can plan for premedication prior to future
contrast examinations or can consider the use of a different type of
imaging procedure. It is helpful to provide patients with both verbal
and written instructions on the signs and symptoms of possible delayed
reactions as well as contact phone numbers in case problems or questions
arise once the patient leaves the radiology department.
While nonionic contrast agents and
gadolinium agents result in few reactions, most of which are mild
reactions, the importance of proper screening of patients prior to the
administration of contrast and being prepared with the proper
medications and equipment in the event of a reaction cannot be
underestimated. Establishing a screening process for patients undergoing
contrast-enhanced examinations can increase efficiency and patient
safety in a busy practice setting. Since reactions are uncommon, it is
important to hold periodic reviews of this information and to have
printed materials available for reference when these events occur.
- Lasser EC, Berry CC. Nonionic vs ionic contrast media: What do the data tell us? AJR Am J Roentgenol. 1989;152:945-946.
- Nelson KL, Gifford LM, Lauber-Huber C, et al. Clinical safety of gadopentetate dimeglumine. Radiology. 1995;196:439-443.
EC, Berry CC, Talner LB, et al. Pretreatment with corticosteroids to
alleviate reactions to intravenous contrast material. N Engl J Med. 1987;
- Lasser EC. Pretreatment with corticosteroids to
prevent reactions to IV contrast material: Overview and implications.
AJR Am J Roentgenol. 1988; 150:257-259.
- Lasser EC, Berry CC,
Mishkin MM, et al. Pretreatment with corticosteroids to prevent adverse
reactions to nonionic contrast media. AJR Am J Roentgenol.
1994;162:523-526. Comments in: AJR Am JRoentgenol. 1994;162:527-529 and in
AJR Am JRoentgenol. 1995;164:508-509.
- Greenberger PA, Patterson
R. The prevention of immediate generalized reactions to radiocontrast
media in high-risk patients. J Allergy Clin Immunol. 1991;87:867-872.
PA, Patterson R, Radin RC. Two pretreatment regimens for high-risk
patients receiving radiographic contrast media. J Allergy Clin
Immunol. 1984;74(4 Pt1):540-543.
- Cochran ST, Bomyea K. Trends in adverse events from iodinated contrast media. Acad Radiol. 2002;9(suppl 1):S65-S68.
JE, Birnbaum BA, Langlotz CP. Contrast media reactions and
extravasation: Relationship to intravenous injection rates.
Radiology. 1998; 209:411-416.
- Grant KL, Carmamo JM. Adverse
events and cost savings three years after implementation of guidelines
for outpatient contrast-agent use. Am J Health Syst
- Cohan RH, Bullard MA, Ellis JH, et al.
Local reactions after injection of iodinated contrast material:
Detection, management, and outcome. Acad Radiol. 1997;4:711-718.