Hypersensitivity Reactions to Multiple Iodinated Contrast Media

Case Report: A Rare Case of Iodixanol-Induced Anaphylactic Shock in Cerebral Angiography

Background

Adverse reactions induced by isoosmolar contrast medium (iodixanol) are mostly mild, with rashes and headaches being the most common. Although anaphylactic shock has been reported, no related incidents have been documented on cerebral angiography.

Objective

This article reports a serious case of anaphylactic shock possibly induced by iodixanol and provides an overview of the case report.

Case Summary

A 65-year-old female with persistent headaches for nearly six months and CTA examination revealed multiple intracranial aneurysms. After two treatments, she returned to the hospital for aneurysm of reexamination a month ago. Following a preoperative assessment, cerebral angiography was performed. Three minutes after the procedure, the patient experienced dizziness, increased heart rate, followed by hypotension (BP 90/43 mm Hg), a sudden drop-in heart rate (HR 68 bpm), and a drop in SpO2 to 92%. Intravenous dexamethasone for anti-allergic were administered immediately, along with therapy through oxygen-inhalation. However, the patient then developed limb convulsions, unresponsiveness, and was urgently given diazepam for sedation and sputum aspiration to maintain airway patency. Blood pressure decrease to 53/29 mm Hg, and SpO2 readings were unavailable. Intravenous dopamine to elevates blood pressure, and assists breathing by intubating in the endotracheal. After 3 minutes, as the blood pressure remained undetectable, intermittent intravenous epinephrine 1mg was administered to raise the blood pressure, gradually restoring it to 126/90 mm Hg, and SpO2 increased to 95%. The patient was diagnosed with iodixanol-induced anaphylactic shock and urgently transferred to the NICU for monitoring and treatment. The patient died despite immediate treatment.

Conclusion

A 65-year-old female developed serious anaphylactic shock during cerebral angiography after receiving iodixanol. Although iodixanol is considered one of the safest iodinated contrast mediums (ICM), clinicians should be aware of its the potential for serious hypersensitivity reactions that can lead to fatal and life-threatening events.

Changing patterns in the epidemiology of drug allergy

Drug allergy (DA) remains a complex and unaddressed problem worldwide that often deprives patients of optimal medication choices and places them at risk for life-threatening reactions. Underdiagnosis and overdiagnosis are common and due to the lack of standardized definitions and biomarkers. The true burden of DA is unknown, and recent efforts in data gathering through electronic medical records are starting to provide emerging patterns around the world. Ten percent of the general population engaged in health care claim to have a DA, and the most common label is penicillin allergy. Up to 20% of emergency room visits for anaphylaxis are due to DA and 15%-20% of hospitalized patients report DA. It is estimated that DA will increase based on the availability and use of new and targeted antibiotics, vaccines, chemotherapies, biologicals, and small molecules, which are aimed at improving patient's options and quality of life. Global and regional variations in the prevalence of diseases such as human immunodeficiency virus and mycobacterial diseases, and the drugs used to treat these infections have an impact on DA. The aim of this review is to provide an update on the global impact of DA by presenting emerging data on drug epidemiology in adult and pediatric populations.

EAACI/ENDA position paper on drug provocation testing

In drug hypersensitivity, drug provocation testing (DPT), also called drug challenge, is the gold standard for investigation. In recent years, risk stratification has become an important tool for adjusting the diagnostic strategy to the perceived risk, whilst still maintaining a high level of safety for the patient. Skin tests are recommended before DPT but may be omitted in low-risk patients. The task force suggests a strict definition of such low-risk patients in children and adults. Based on experience and evidence from studies of allergy to beta-lactam antibiotics, an algorithm on how to adjust DPT to the risk, and when to omit skin tests before DPT, is presented. For other antibiotics, non-steroidal anti-inflammatory drugs and other drugs, skin tests are poorly validated and DPT is frequently necessary. We recommend performing DPT with chemotherapeutics and biologicals to avoid unnecessary desensitization procedures and DPT with skin tests negative contrast media. We suggest DPT with anesthetics only in highly specialized centers. Specifics of DPT to proton pump inhibitors, anticonvulsants and corticosteroids are discussed. This position paper provides general recommendations and guidance on optimizing use of DPT, whilst balancing benefits with patient safety and optimizing the use of the limited available resources.

Delayed hypersensitivity reactions to iodinated contrast media: A diagnostic approach by skin tests

BACKGROUND

Adverse drug reactions to iodinated contrast media (ICM) have risen due to their increasing use in x-ray-based imaging modalities. Delayed hypersensitivity reactions are mainly caused by nonionic monomeric compounds and represent an issue impacting the diagnostic-therapeutic pathways of cancer, cardiology and surgery patients.

OBJECTIVES

To prospectively evaluate the usefulness of skin tests in delayed hypersensitivity reactions to ICM and to evaluate the tolerability of iobitridol, a monomeric nonionic low osmolality compound, as a possible safe alternative.

METHODS

Patients with delayed hypersensitivity reactions to ICM referred to us from 2020 to 2022 were prospectively enrolled in the study. All patients underwent patch test and, if negative, intradermal test with the culprit ICM and iobitridol as alternative.

RESULTS

A total of 37 patients (females 24, 64.9%) were enrolled in the study. Iodixanol and iomeprol were the most frequently involved ICM (48.5% and 35.2%, respectively); 62.2% of patients presented maculopapular eruption, while 37.8% reported delayed urticaria-like rash. Skin tests resulted positive to the culprit ICM in 19 patients (51.4%), 16 to patch test and 3 to intradermal test. Skin tests with iobitridol, tested as alternative, resulted positive in 3/19 patients (15.8%). All 16 patients with negative results to iobitridol were administered this ICM and tolerated it.

CONCLUSIONS

In at least half of patients, delayed-type hypersensitivity was demonstrated by skin tests, particularly by patch test. This diagnostic approach resulted simple, cost-effective and safe, not only to confirm the culprit ICM but also to identify iobitridol as feasible alternative.

Pharmacist-led iodinated contrast media infusion risk assessment service

Background: With the increasing development of medical imaging, the use of iodinated contrast media has become more widespread. Adverse reactions caused by iodinated contrast media have drawn much attention. Despite this, there is still a lack of unified standards for the safe infusion process of iodinated contrast media in clinical practice both domestically and internationally. Objectives: Establishing a risk management service system to better predict the risks associated with iodinated contrast media infusion, reduce the incidence of adverse reactions and minimize patient harm. Method: A prospective interventional study was carried out from April 2021 to December 2021 at Nanjing Drum Tower Hospital in China. During this study, a service system was established to manage the risks associated with the infusion of iodinated contrast media. Personalized risk identification and assessment were performed by a pharmacist-led multidisciplinary team before iodinated contrast media infusion. Early warning, prevention, and adverse reaction management were performed according to different risk levels during and after infusion. Results: A multidisciplinary team led by pharmacists was established to evaluate the risks associated with infusion of iodinated contrast media. A total of 157 patients with risk factors related to the iodinated contrast media were screened out, which prevented 22 serious adverse events and enhanced the quality of medical care. All participants expressed high satisfaction with the service. Conclusion: Through practical exploration, the pharmacist-led multidisciplinary team can provide advance warning and effectively limit the risks of adverse reactions caused by iodinated contrast media to a preventable and controllable level. This approach serves as a valuable reference for developing strategies and schemes to reduce the incidence of such reactions. Therefore, we encourage the implementation of this intervention in other areas of China.

[Drug allergy: Fundamental aspects in diagnosis and treatment.]

BACKGROUND

Any substance used as a treatment for any disease can produce harmful or unpleasant events called adverse drug reactions (ADRs). They are due to inherent biological effects of the drug and are caused by immunological and non-immunological mechanisms.

OBJECTIVES

To describe the immunological mechanisms of hypersensitivity reactions (HSR) to drugs, their epidemiology, risk factors, classification, clinical manifestations, diagnosis, treatment, and prognosis.

METHODS

A review of the most current literature in English and Spanish was carried out, in the main databases, related to the HSR of various drug groups.

RESULTS

This study describes the terms used to define ADRs and HSRs, their classification and clinical manifestations, current diagnostic tools, treatment algorithms and prognosis of the most frequently used medications and with the highest prevalence of reported adverse events.

CONCLUSION

ADRs are a challenging entity, with a complex pathophysiology that has not been fully understood. Its approach requires a careful consideration since not all drugs have validated tests for their diagnosis nor a specific treatment. When indicating the use of any drug, the severity of the disease, the availability of other treatments and the potential risks of developing future adverse events should always be taken into consideration.

Immediate hypersensitivity reactions to iodinated contrast media: The diagnosis of allergy by skin testing

Among 74 patients with an immediate hypersensitivity reaction (IHR) to iodinated contrast media (ICM), the rate of allergic patients confirmed by positive prick test or diluted intradermal test (IDT) was 8.1%. 12.5% of re-exposed patients had a recurrent IHR despite negative skin tests. Investigations on pure IDT to ICM and development of drug provocation test may provide additional safety nets to uncover recurrent ICM reactors. Agreements among allergists are needed to unify practices.

Gadolinium Enhances Dual-energy Computed Tomography Scan of Pulmonary Artery

OBJECTIVE

To evaluate the feasibility of using gadopentetate dimeglumine (Gd-DTPA) for dual-energy computed tomography pulmonary angiography (CTPA).

METHODS

Sixty-six patients were randomly divided into three groups and underwent CTPA. Group A had a turbo flash scan using an iohexol injection, Group B had a turbo flash scan using Gd-DTPA, and Group C had a dual-energy scan using Gd-DTPA. The original images of Group C were linearly blended with a blending factor of 0.5 or reconstructed at 40, 50, 60, 70, 80, 90, 100, and 110 keV, respectively. The groups were compared in terms of pulmonary artery CT value, image quality, and radiation dose.

RESULTS

The pulmonary artery CT values were significantly higher in Group C_40keV than in Groups B and C, but lower than in Group A. There was no significant difference in the image noise of Groups C_40keV, B, and C. Moreover, Group A had the largest beam hardening artifacts of the superior vena cava (SVC), followed by Groups B and C. Group C_40keV showed better vascular branching than the other three groups, among which Group B was superior to Group A. The subjective score of the image quality of Groups A, B, and C showed no significant difference, but the score was significantly higher in Group C_40keV than in Groups A and B. The radiation dose was significantly lower in Group B than in Groups A and C.

CONCLUSION

Gd-CTPA is recommended to patients who are unsuitable for receiving an iodine-based CTPA. Furthermore, a turbo flash scan could surpass a dual-energy scan without consideration for virtual monoenergetic imaging.

Validation of Practical Pathway in Patients With Anaphylaxis to Low Osmolar Contrast Media: A Retrospective Cohort Study

BACKGROUND

An optimal strategy for choosing safe alternative low osmolar contrast media (LOCM) has not yet been established in patients with a history of LOCM-induced anaphylaxis.

OBJECTIVES

To validate the practical pathway in patients with anaphylaxis to LOCMs and to compare 2 different doses of challenge testing with skin test-negative LOCM.

METHODS

A retrospective cohort study was performed in patients with LOCM-induced anaphylaxis. Patients were challenged with intravenous LOCMs showing negativity in the skin test according to 2 different protocols: low-dose and high-dose (maximum dose 10 and 30 mL, respectively). Challenge-negative LOCMs were selected for use during computed tomography scans, and patients received intravenous pretreatment with 4 mg chlorpheniramine and 40 mg methylprednisolone.

RESULTS

Of the 110 challenge tests, there were 4 (3.6%) positive challenges. Among 106 enhanced computed tomography scans performed using challenge-negative LOCMs, breakthrough reactions occurred in 8 (7.6%). Breakthrough reaction rates were not statistically different between the 2 protocols (8.9% and 6.0% in the low-dose challenge and the high-dose challenge, respectively). Compared with the low-dose protocol, the number needed to test of the high-dose challenge test decreased 2.5-fold. Moreover, none of the patients in the high-dose challenge group incurred severe reactions during computed tomography scans with challenge-negative LOCM, whereas 80% of reactions were severe in the low-dose challenge group.

CONCLUSIONS

We validated a pathway consisting of a battery of skin testing to LOCMs and challenge with skin test-negative LOCM in patients with LOCM-induced anaphylaxis.

Diagnosing and Managing Patients with Reactions to Radiocontrast Media

Purpose of the review

Iodinated radio contrast media (RCM) belong to the most common elicitors of drug hypersensitivity reactions (HR). Urticaria or anaphylaxis may occur ≤ 1(−6) hour(s) (immediate HR) and exanthems (non-immediate HR) develop > 6 h after application of RCM. Evidence for an immunologic mechanism of RCM HR against the different RCM benzene ring molecules and the benefit of allergological testing in patients with previous hypersensitivity reactions is progressively increasing.

Recent findings

Positive skin tests can confirm allergy in patients with previous reactions to RCM and help to select alternative better tolerated RCMs. Severe hypersensitivity reactions are mainly caused by an allergic mechanism, whereas the majority of non-severe reactions appear to be non-allergic. Skin testing is highly recommended to help identify allergic hypersensitivity reactions and to select alternatives. Using structurally different RCM is more effective than premedication for the prevention of future reactions. Drug provocation tests to RCM have been increasingly used, but are not yet standardized among different centers.

Summary

In patients with previous severe hypersensitivity reactions to RCM, skin testing is recommended. For future RCM-enhanced examinations in patients with previous reactions, structurally different, skin test-negative preparations should be applied. Drug provocation tests do confirm or exclude RCM hypersensitivity or may demonstrate tolerability of alternative RCMs.

Assessment of immediate and non-immediate hypersensitivity contrast reactions by skin tests and provocation tests: A review

INTRODUCTION

Allergic and nonallergic hypersensitivity reactions to iodinated contrast media (ICM) and gadolinium-based contrast media are classified as immediate or non-immediate hypersensitivity reactions (IHR and NIHR), respectively. Skin tests and provocation tests are recommended for the evaluation of hypersensitivity reactions to contrast agents; however provocations are not common in clinical practice.

METHODS

A MEDLINE search was conducted to investigate studies comprising both skin tests and provocation tests that evaluated hypersensitivity reactions to ICM.

RESULTS

Nineteen studies were identified that reported on skin tests, followed by provocations. In the case of IHR to ICM, 65/69 (94%) patients with a positive skin test for the culprit media tolerated a challenge with a skin-test-negative alternative ICM. In IHR to ICM with a negative skin test for the culprit media, provocations were positive in 3.2%-9.1% patients. In the case of a NIHR to ICM with a positive skin test, provocation with a skin-test-negative agent was tolerated in 75/105 (71%) of cases. In NIHR with a negative skin test for the culprit agent, re-exposure to the culprit or an alternative was positive in 0%-34.6% patients. Provocations with the same ICM in skin test positive patients with IHR or NIHR were positive for a majority of the patients, although such provocation tests were rarely performed. Data on hypersensitivity reactions, skin tests and provocations with gadolinium-based contrast media were limited; however, they exhibited a pattern similar to that observed in ICM.

CONCLUSION

In both ICM and gadolinium-based contrast media, the risk of an immediate repeat reaction is low when skin tests are negative. In contrast, a provocation with a skin-test-positive contrast medium showed a high risk of an immediate repeat hypersensitivity reaction. Therefore, a thorough medical history is necessary, followed by skin tests. A provocation is recommended, for diagnostic work-up, when the diagnosis is uncertain.