Skin tests in patients with hypersensitivity reaction to iodinated contrast media: a meta-analysis

Incidence of Breakthrough Reaction in Patients with Prior Acute Allergic-Like Reactions to Iodinated Contrast Media according to the Administration Route

Objective

This study assessed the risk of acute allergic-like reactions (AARs) after extravascular administration of iodinated contrast media (ICM) in at-risk patients compared with that after intravascular ICM administration.

Materials and Methods

From July 2012 to January 2016, 264 patients with a history of moderate or severe reactions to ICM, with re-exposure to ICM intravascularly or extravascularly were included. The incidence of recurrent AARs after ICM re-exposure were assessed according to the administration routes by reviewing electronic medical records and comparison between the two routes.

Results

Among 264 patients, 244 patients had been subsequently exposed to ICM intravascularly, 7 patients via an extravascular route and 13 patients with dual re-exposure. Of 257 patients with intravascular ICM re-exposure, 87 (33.9%) had mild to severe recurrent AARs and 143 (19.5%) cases of recurrent AARs occurred among 733 cases of intravascular ICM re-exposure on a case-by-case basis. However, there was no case of recurrent ARR after extravascular administration of ICM in 20 patients (45 cases) with ICM administrated extravascularly.

Conclusion

For high-risk patients with a history of moderate or severe reactions to ICM, AARs upon extravascular administration of ICM are significantly infrequent compared with intravascular ICM administration.

Immediate Allergic Reactions to Gadolinium-based Contrast Agents: A Systematic Review and Meta-Analysis

Purpose To perform a systematic review and meta-analysis to determine if there are differences in rates of immediate allergic events between classes of gadolinium-based contrast agents (GBCAs). Materials and Methods PubMed and Google Scholar databases were searched for studies in which rates of immediate adverse events to GBCAs were reported. The American College of Radiology classification system was used to characterize allergic-like events as mild, moderate, or severe, and the total number of administrations of each GBCA was recorded. Where necessary, authors of studies were contacted to clarify data and eliminate physiologic reactions. Relative risks of GBCA types were estimated by using the Mantel-Haenszel type method. Results Nine studies in which immediate reactions to GBCA were recorded from a total of 716 978 administrations of GBCA met the criteria for inclusion and exclusion. The overall rate of patients who had immediate allergic-like reactions was 9.2 per 10 000 administrations and the overall rate of severe immediate allergic-like reactions was 0.52 per 10 000 administrations.. The nonionic linear chelate gadodiamide had the lowest rate of reactions, at 1.5 (95% confidence interval [CI]: 0.74, 2.4) per 10 000 administrations, which was significantly less than that of linear ionic GBCAs at 8.3 (95% CI: 7.5, 9.2) per 10 000 administrations (relative risk, 0.19 [95% CI: 0.099, 0.36]; P < .00001) and less than that for nonionic macrocyclic GBCAs at 16 (95% CI: 14, 19) per 10 000 administrations (relative risk, 0.12 [95% CI: 0.05, 0.31]; P < .001). GBCAs known to be associated with protein binding had a higher rate of reactions, at 17 (95% CI: 15, 20) per 10 000 administrations compared with the same chelate classification without protein binding, at 5.2 (95% CI: 4.5, 6.0) per 10 000 administrations (relative risk, 3.1 [95% CI: 2.4, 3.8]; P < .0001). Conclusion These data show the lowest rate of immediate allergic adverse events with use of the nonionic linear GBCA gadodiamide in comparison with those of ionic linear or nonionic macrocyclic GBCAs. A higher rate of immediate allergic adverse events was associated with ionicity, protein binding, and macrocyclic structure. © RSNA, 2017 An earlier incorrect version of this article appeared online. This article was corrected on August 31, 2017.

Qualitative and quantitative radiological analysis of non-contrast CT is a strong indicator in patients with acute pyelonephritis

OBJECTIVE

To evaluate the performance of non-contrast computed tomography (CT) by reporting the difference in attenuation between normal and inflamed renal parenchyma in patients clinically diagnosed with acute pyelonephritis (APN).

MATERIAL AND METHODS

This is a retrospective study concerned with non-contrast CT evaluation of 74 patients, admitted with a clinical diagnosis of APN and failed to respond to 48h antibiotics treatment. Mean attenuation values in Hounsfield units (HU) were measured in the upper, middle and lower segments of the inflamed and the normal kidney of the same patient. Independent t-test was performed for statistical analysis. Image evaluation included receiver operating characteristic (ROC), visual grading characteristic (VGC) and kappa analyses.

RESULTS

The mean attenuation in the upper, middle and lower segments of the inflamed renal cortex was 32%, 25%, and 29% lower than the mean attenuation of the corresponding cortical segments of the contralateral normal kidney, respectively (p<0.01). The mean attenuation in the upper, middle, and lower segments of the inflamed renal medulla was 48%, 21%, and 30%, lower than the mean attenuation of the corresponding medullary segments of the contralateral normal kidney (p<0.02). The mean attenuation between the inflamed and non-inflamed renal cortex and medulla was 29% and 30% lower respectively (p<0.001). The AUCROC (p<0.001) analysis demonstrated significantly higher scores for pathology detection, irrespective of image quality, compared to clinical and laboratory results with an increased inter-reader agreement from poor to substantial.

CONCLUSION

Non-contrast CT showed a significant decrease in the parenchymal density of the kidney affected with APN in comparison to the contralateral normal kidney of the same patient. This can be incorporated in the diagnostic criteria of APN in NCCT in the emergency setting.

Outcomes of corticosteroid prophylaxis for hypersensitivity reactions to low osmolar contrast media in high-risk patients

BACKGROUND

Corticosteroid prophylaxis has been widely adopted for the prevention of acute allergic-like reactions to iodinated contrast media, but its use is still controversial because there is no strong evidence supporting its efficacy before administration of nonionic low osmolar contrast media (LOCM).

OBJECTIVE

To assess the outcomes of premedication in patients with previous acute allergic-like reactions to LOCM in clinical practice.

METHODS

A retrospective study was performed on 322 high-risk patients who were reexposed to LOCM after premedication composed of antihistamines and/or systemic corticosteroids because of a previous history of acute allergic-like reactions to LOCM.

RESULTS

After premedication, 275 patients (85.4%) did not experience any reaction, but 47 patients (14.6%) still experienced a breakthrough reaction. The premedication rate and amount of corticosteroid administered were significantly higher in the nonrecurrence group than in the recurrence group (P = .04 and P = .04, respectively), and a linear trend was observed in the use of corticosteroid premedication and the efficacy of prevention (P for trend = .02). Multivariate binary logistic regression revealed that corticosteroid premedication was effective in preventing recurrence (odds ratio, 0.284; 95% confidence interval, 0.103-0.784). Nonetheless, despite corticosteroid premedication, 3.4% of high-risk patients still experienced moderate to severe reactions, and 14.3% of patients with a severe index reaction again had a severe reaction.

CONCLUSION

Premedication with corticosteroids seems to be helpful in reducing the overall rate of recurrence of acute allergic-like reactions to LOCM in high-risk patients, but patients with severe index reactions are still at risk of developing severe reactions despite corticosteroid premedication.

Successful desensitization to radiocontrast media in two high-risk cardiac patients

Hypersensitivity reactions to radiocontrast media (RCM) are common and in severe cases may present a challenge for treating physician in cases when premedication fails or the patient presents with severe comorbidities. We describe two cases in need of radiocontrast media after a severe reaction on previous exposure to iohexol. One presented anaphylactic reaction to RCM despite premedication and another presented with angina. Both cases were treated with a desensitization protocol to iodixanol. In conclusion, desensitization to radiocontrast media may be considered in patients with previously unsuccessful premedication and/or severe acute comorbidities.

SIMILAR CASES PUBLISHED

14.

Stratified premedication strategy for the prevention of contrast media hypersensitivity in high-risk patients

BACKGROUND

Although the severity of hypersensitivity reactions to iodinated contrast media varies, it is well correlated with the severity of recurrent reactions; however, prophylaxis protocols are not severity-stratified.

OBJECTIVE

To assess the outcomes of tailored prophylaxis according to the severity of hypersensitivity reactions to iodinated contrast media.

METHODS

Our premedication protocols were stratified based on the severity of previous reactions: (1) 4 mg of chlorpheniramine for mild reactions, (2) adding 40 mg of methylprednisolone for moderate reactions, and (3) adding multiple doses of 40 mg of methylprednisolone for severe index reactions. Cases of reexposure in patients with a history of hypersensitivity reactions were routinely monitored and mandatorily recorded.

RESULTS

Among a total of 850 patients who underwent enhanced computed tomography after severity-tailored prophylaxis, breakthrough reactions occurred in 17.1%, but most breakthrough reactions (89.0%) were mild and did not require medical treatment. Additional corticosteroid use did not reduce the breakthrough reaction rate in cases with a mild index reaction (16.8% vs 17.2%, P = .70). However, underpremedication with a single dose of corticosteroid revealed significantly higher rates of breakthrough reaction than did double doses of corticosteroid in cases with a severe index reaction (55.6% vs 17.4%, P = .02). Changing the iodinated contrast media resulted in an additional reduction of the breakthrough reaction rate overall (14.9% vs 32.1%, P = .001).

CONCLUSION

In a total severity-based stratified prophylaxis regimens and changing iodinated contrast media can be considered in patients with a history of previous hypersensitivity reaction to iodinated contrast media to reduce the risk of breakthrough reactions.

Immediate hypersensitivity to iodinated contrast media: diagnostic accuracy of skin tests and intravenous provocation test with low dose

BACKGROUND

The diagnosis of HSR to iodinated contrast media (ICM) is challenging based on clinical history and skin tests.

OBJECTIVE

This study evaluates the negative predictive value (NPV) of skin tests and intravenous provocation test (IPT) with low-dose ICM in patients with suspected immediate hypersensitivity reaction (HSR) to ICM.

METHODS

Thirty-seven patients with suspected immediate hypersensitivity reaction to ICM were included retrospectively. Skin tests and a single-blind placebo-controlled intravenous provocation test (IPT) with low-dose iodinated contrast media (ICM) were performed.

RESULTS

Skin tests with ICM were positive in five cases (one skin prick test and five intradermal test). Thirty-six patients were challenged successfully by IPT, and only one patient had a positive challenge result, with a grade I reaction by the Ring and Messmer classification. Ten of 23 patients followed up by telephone were re-exposed to a negative tested ICM during radiologic examination; two experienced a grade I immediate reaction.

CONCLUSIONS & CLINICAL RELEVANCE

For immediate hypersensitivity reaction to ICM, the NPV for skin tests and IPT with low dose was 80% (95% CI 44-97%).

[Recurrence of drug eruption after renewed injection of iodinated contrast medium in patients with known allergic contraindications]

BACKGROUND

Iodinated contrast media (ICM) are used extensively by both radiologists and cardiologists. Injection of such products can induce immediate hypersensitivity reactions, some of which are IgE-mediated, and delayed hypersensitivity reaction with all types of drug eruptions being reported. Allergy tests, whether patch-tests or intradermal tests, are useful to confirm whether patients are allergic. At the end of these tests, depending on the reaction (chronology and clinical symptoms) and the results of the skin tests, patients are given an allergy card as well as a detailed certificate indicating the various ICM contraindicated and those allowed.

OBSERVATIONS

We report herein three cases of patients experiencing a confirmed allergic eruption after injection of ICM, and whose recommendations and contraindication were not taken into consideration, leading to recurrence of eruption after renewed ICM injection.

DISCUSSION

The three cases we report herein underscore the lack of knowledge concerning eruptions induced by ICM, particularly among radiologists. Better dissemination of information about the existence of such reactions appears necessary amongst the medical professionals concerned.