Reactions to contrast media

Arnold AW, Hausermann P, Bach S, Bircher AJ Recurrent flexural exanthema (SDRIFE or baboon syndrome) after administration of two different iodinated radiocontrast media. Dermatology 2007 214 89-93. Laroche D Immediate reactions to contrast media mediator release and value of diagnostic testing. Toxicology 2005 209 193-194. 

Kwak R A case of shock by pretesting of contrast media (in Japanese). Rinsho Hoshasen 1985 30 407M09. Morcos SK, Thomsen HS, Webb JA Prevention of generalized reactions to contrast media a consensus report and guidelines. Eur Radiol 2001 11 1720-1728. Tramer MR, von Elm E, Loubeyre P, Hauser C Pharmacological prevention of serious anaphylactic reactions due to iodinated contrast media systematic review. BMJ 2006 333 675. 

Thomsen HS, Morcos SK. Management of acute adverse reactions to contrast media. Eur Radiol 2004 14 476-481. 

To reduce the incidence of generalized reactions to contrast media in high-risk patients some authors have advocated the prophylactic administration of glucocorticoids (prednisolone 30 mg orally or methylprednisolone 32 mg orally, 12 and 2 hours before contrast injections). In one case an acute psychosis complicated glucocorticoid premedication to reduce the risk of contrast reactions (413). 

A 13-year-old girl with bipolar disorder and a history of adverse reactions to contrast media was given methylprednisolone (32 mg/day) and ranitidine (300 mg/day) before a CT scan of the head with intravenous contrast enhancement. One day after, she developed psychiatric symptoms, which were more severe than her initial symptoms, including extreme agitation and mental confusion. All medications were withdrawn and her symptoms resolved within 2 weeks. 

Freidy J F 1988 Reactions to contrast media and steroid pretreatment. British Medical Journal 296 ... 

Choyke PL, Miller DL, Lotze MT, Whiteis JM, Ebbitt B, Rosenberg SA. Delayed reactions to contrast media after interleukin-2 immunotherapy. Radiology 1992 183(1) 111-14. 

In various earlier surveys of conventional ionic contrast media, the incidence of minor reactions was one in 13-30 cases, the incidence of intermediate reactions one in 57-130 cases, and the incidence of severe reactions one in 1000-4000 cases. The figures for the non-ionic media are much more favorable. In 1990, the Japanese Committee on the Safety of Contrast Media surveyed 169 284 patients who had received ionic media and 168 363 who had received non-ionic contrast media (14). In patients with a previous history of reactions to contrast media, the incidence of severe reactions was 0.73% with ionic media and only 0.18% with non-ionic media. Among patients with asthma, severe and very severe reactions occurred in 1.88% with ionic media and 0.23% with non-ionic media. In a Canadian survey of 1992, the overall incidence of adverse effects to contrast media was 3.9% for ionic media and only 0.9% for non-ionic media, despite the fact that the proportion of patients with heart disease as a pre-existing susceptibility factor was much higher in the non-ionic group (SEDA-22, 500). 

Adverse reactions to intravascular iodinated agents are usually classified as minor, intermediate, or severe life-threatening. All types of reactions to low-osmolar contrast media are five times less common than reactions to high-osmolar contrast agents (SEDA-22, 489) (SEDA-23, 494) (SEDA-24, 519), and very severe adverse reactions to contrast media are rare, with a frequency of about 0.04% with high-osmolar agents and 0.004% with low-osmolar agents. However, there are no important differences in the safety profiles of the different low-osmolar non-ionic monomers (18). 

In another survey, the incidence of contrast media reactions after intravenous administration was evaluated over 14 years (25). The incidence of all reactions to contrast media was 6-8% with high-osmolar contrast media and only 0.2% with low-osmolar non-ionic agents. Most of the reactions (over 90%) were aUergic-like, and severe reactions were rare (0.05%). One death was reported after the use of a low-osmolar agent. These data are compatible with previous reports, which showed that low-osmolar contrast media have a much better safety profile than high-osmolar media and that there is no significant difference in the incidence of acute adverse reactions between non-ionic dimeric and monomeric contrast media. 

Most severe reactions to contrast media are associated with cardiovascular manifestations, causing hypotensive shock and in some cases ventricular fibrillation and cardiac arrest these events are reversible in most cases in which prompt treatment is given. In a case of hypotensive collapse reported in 1977, and followed by a small number of others, there was disseminated intravascular coagulation (50). In milder cases there is only hypotension, which can be transient and symptomless in some cases there is bradycardia (due apparently to vagal overactivity) rather than tachycardia. 

This reaction shared the features of a delayed hypersensitivity reaction (exanthematous rash, positive patch test) and of a late phase reaction (CD4+ lymphocjdic infiltrate together with eosinophils). The authors emphasized the importance of skin testing in the diagnosis of delayed skin reactions to contrast media. 

Prophylactic use of immunosuppression has been described to prevent delayed hypersensitivity reactions to contrast media (227). 

Racial differences could be a factor in the high incidence of delayed skin reactions to contrast media in Japan, as 43% of Japanese are deficient in acetaldehyde dehydrogenase. This deficiency results in the accumulation of acetaldehyde, which potentiates the ability of contrast agents (especially dimers), to bridge proteins, which is a probable causative factor in many of their adverse effects (11). 

Patients with a history of previous reactions to contrast media have a 35 0% chance of reacting again if reexamined. 

Field experience, backed by a case-control study of 1991, strongly suggests that patients taking beta-blockers have a risk ratio of adverse reactions to contrast media of 2.7. Hypotension is the main effect, sometimes dangerously so, even with non-ionic media (SEDA-11, 411) (SEDA-17, 536) (311). 

Katayama H, Tanaka T. Clinical survey of adverse reactions to contrast media. Invest Radiol 1988 23 (Suppl l) S88-9. 

Table 95.6 Treatment of serious acute reactions to contrast media...

Limited documentation. Withdrawal of the beta blocker 2 to 3 days before use of contrast media has been suggested, but because of the potential for beta blocker withdrawal syndromes this must be considered on an individual risk/benefit basis. Pretreatment with an antihistamine such as diphenhydramine and a corticosteroid such as prednisone may reduce the risk of reactions. Ephedrine and cimetidine have also been tried, but their use is controversial. Use of low osmolality, non-ionic contrast media may reduce the risk of adverse reactions, including anaphylaxis. However, even mild reactions to contrast media may sensitise the patient and a serious anaphylactoid reaction may occur on further exposure despite pretreatment and the use of low osmolality contrast media. Pre-testing with a small amount of the contrast media has been shown to be a poor predictor of a reaction. ... 

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