The involvement of osmolarity in the safety of contrast media

A Case of Severe Lethal Allergic Reaction Caused by Iodixanol After Digital Subtraction Angiography

BACKGROUND

Severe lethal allergic reactions triggered by iodixanol following digital subtraction angiography (DSA) are rare. The majority of skin reactions associated with iodixanol were mild, and the prognosis was favorable. Moreover, a case of serious skin adverse events caused by iodixanol has been documented.

METHODS

A 61-year-old woman underwent surgery for a cerebral hemorrhage in another hospital. Upon the surgery, the patient's state of impaired consciousness did not show any improvement. Head computed tomography angiography on admission: right middle cerebral artery M1 segment enlargement, left posterior cerebral artery P2 stenosis. Following undergoing DSA with iodixanol, the patient experienced severe and fatal drug eruptions, which represents a serious and uncommon complication associated with iodixanol.

RESULTS

This paper describes the experience in the treatment and nursing of severe allergic reactions. Despite the fact that the patient was discharged automatically and eventually died, there are valuable lessons to be learned from this case that can inform and guide future clinical practices.

CONCLUSIONS

Iodixanol adverse reactions were rare, and severe fatal adverse reactions were seldom reported. Consequently, the authors conclude that the potential adverse reaction risk of iodixanol contrast agent should be taken into consideration in future endeavors, and the skin and allergy of patients should be monitored following DSA. In an allergy, prompt and proactive treatment is essential to prevent worsening and dissemination.

Bridging the gap between bench and clinic: the importance of understanding the mechanism of iodinated contrast media hypersensitivity

Since the advent of CT, iodinated contract media (ICM) has become one of the most regularly administered intravenous medications in clinical settings. Although considered generally safe, ICM is one of the most common causes of adverse drug reactions in clinical practice, accounting for more than 2 million adverse reactions worldwide. Currently, there are few useful tools to diagnose patient hypersensitivity, with the major limitation being the lack of consensus regarding the mechanisms of hypersensitivity to ICM. While there is an overwhelming abundance of literature pertaining to clinical features including incidence, symptomatology, and risk, few studies have further investigated the underlying mechanisms behind their clinical observations. Of the available literature discussing pathophysiology, most primary studies were completed over 20 years ago, since which the molecular characteristics of ICM have changed. Furthermore, many reviews mentioning pathophysiology fail to adequately emphasize the clinical importance of understanding the molecular pathways involved in hypersensitivity. In this review, we aim to emphasize the clinical relevance of pathophysiology as it relates to the prediction and diagnosis of hypersensitivity reactions to ICM. To this end, we will first briefly characterize hypersensitivity reactions to ICM with respect to epidemiology and clinical presentation. We will then present the existing evidence supporting various proposed mechanisms of hypersensitivity, highlighting the gaps that remain in the mechanistic delineation of both immediate and delayed reactions. Finally, we discuss the possibility of in vitro testing as a way to predict and diagnose hypersensitivity reactions, pending a more complete elucidation of mechanisms.

Intradermal Testing With Radiocontrast Media to Prevent Recurrent Adverse Reactions

OBJECTIVE. Adverse drug reactions (ADRs) to radiocontrast media are a significant social and economic burden and are difficult to predict. Because some ADRs to radiocontrast media may be immunologically induced, a skin test with diluted 1:10 radiocontrast media has been used to predict ADRs. However, using this test in clinical practice is difficult because of its low sensitivity. SUBJECTS AND METHODS. This study enrolled 36 patients with a history of immediate ADR to radiocontrast media who visited the Allergy and Asthma Clinic of Severance Hospital from 2017 to 2018. Patients underwent intradermal testing (IDT) with five types of diluted (1:10) and undiluted radiocontrast media (iohexol, iobitridol, iopamidol, iopromide, and iodixanol). The IDT result was regarded as positive if at least one radiocontrast medium elicited a positive reaction. Positivity of IDT and sensitivity to the culprit radiocontrast medium were calculated and compared. For subsequent CT examinations with a radiocontrast medium, the contrast agent eliciting a negative skin reaction in IDT was selected, excluding the previous culprit radiocontrast medium. RESULTS. IDT positivity and sensitivity for the culprit radiocontrast medium at 1:10 dilution were 47.2% and 47.2%, respectively, whereas the positivity and sensitivity for the undiluted radiocontrast medium were 86.1% and 75.0%, respectively. The positivity and sensitivity were higher with frequent radiocontrast medium use or with severe reaction. Of 22 patients who underwent another CT examination with the contrast medium selected on the basis of IDT results, 21 (95.5%) did not experience an ADR. CONCLUSION. IDT to prevent ADR should be performed with undiluted radiocontrast medium. Selecting an alternative radiocontrast agent on the basis of IDT results can be clinically useful to prevent recurrent ADRs to radiocontrast media.