Current understanding of contrast media reactions and implications for clinical management

Contrast Reactions and Approaches to Staffing the Contrast Reaction Management Team

RATIONALE AND OBJECTIVES

Managing contrast reactions is critical as contrast reactions can be life-threatening and unpredictable. Institutions need an effective system to handle these events. Currently, there is no standard practice for assigning trainees, radiologists, non-radiologist physicians, or other non-physician providers for management of contrast reaction.

MATERIALS AND METHODS

The Association of Academic Radiologists (AAR) created a task force to address this gap. The AAR task force reviewed existing practices, studied available literature, and consulted experts related to contrast reaction management. The Society of Chairs of Academic Radiology Departments (SCARD) members were surveyed using a questionnaire focused on staffing strategies for contrast reaction management.

RESULTS

The task force found disparities in contrast reactions management across institutions and healthcare providers. There is a lack of standardized protocols for assigning personnel for contrast reaction management.

CONCLUSION

The AAR task force suggests developing standardized protocols for contrast reaction management. The protocols should outline clear roles for different healthcare providers involved in these events.

Assessing the clinical utility of abdominal computed tomography in sepsis patients with unknown origin: A retrospective cohort study

Early identification of the sources of infection in emergency department (ED) patients of sepsis remains challenging. Computed tomography (CT) has the potential to identify sources of infection. This retrospective study aimed to investigate the role of CT in identifying sources of infection in patients with sepsis without obvious infection foci in the ED. A retrospective chart review was conducted on patients with fever and sepsis visiting the ED of Linkou Chang Gung Memorial Hospital between July 1, 2020 and June 30, 2021. Data on patient demographics, vital signs, clinical symptoms, underlying medical conditions, laboratory results, administered interventions, length of hospital stay, and mortality outcomes were collected and analyzed. Of 218 patients included in the study, 139 (63.8%) had positive CT findings. The most common sources of infection detected by CT included liver abscesses, acute pyelonephritis, and cholangitis. Laboratory results showed that patients with positive CT findings had higher white blood cell and absolute neutrophil counts and lower hemoglobin levels. Positive blood culture results were more common in patients with positive CT findings. Additionally, the length of hospital stay was longer in the group with positive CT findings. Multivariate logistic regression analysis revealed that hemoglobin levels and positive blood culture results independently predicted positive CT findings in patients with fever or sepsis without an obvious source of infection. In patients with sepsis with an undetermined infection focus, those presenting with leukocytosis, anemia, and elevated absolute neutrophil counts tended to have positive findings on abdominal CT scans. These patients had high rates of bacteremia and longer lengths of stay. Abdominal CT remains a valuable diagnostic tool for identifying infection sources in carefully selected patients with sepsis of undetermined infection origins.

Angioedema From Triple Therapy: A Case Report

Angioedema is a rare but potentially life-threatening complication associated with angiotensin-converting enzyme (ACE) inhibitors. Although the pathophysiology is well understood, cases involving the concurrent use of other medications are less explored. We present a unique case of ACE inhibitor-induced angioedema in a 57-year-old male, which developed soon after receiving intravenous contrast. The patient's medication list included a dipeptidyl peptidase-IV inhibitor and a calcium channel blocker. Studies have shown an increased risk of angioedema with the combined use of these medications, likely due to alterations in bradykinin metabolism. This case highlights the importance of medication review and consideration of potential drug interactions when prescribing ACE inhibitors. It emphasizes the significance of diagnostic accuracy to avoid the mislabeling of allergies and consideration of other etiologies in angioedema. Healthcare providers ought to be mindful of the increased risk of angioedema when prescribing dipeptidyl peptidase-IV inhibitors and calcium-channel blockers with ACE inhibitors, as these are frequently used medications.

Clinical features and risk factors of iodinated contrast media (ICM)-induced anaphylaxis

PURPOSE

To evaluate the clinical features and risk factors of iodinated contrast media (ICM)-induced anaphylaxis.

METHODS

This retrospective study included all patients undergoing contrast-enhanced computed tomography (CT) with intravenous ICM administration (iopamidol, iohexol, iomeprol, iopromide, ioversol) at our hospital between April 2016 and September 2021. Medical records of patients who experienced anaphylaxis were reviewed, and the multivariable regression model using generalized estimating equations was employed to eliminate the effect of intrapatient correlation.

RESULTS

Of the 76,194 ICM administrations (44,099 men [58 %] and 32,095 women; age, median, 68 years) to 27, 696 patients, anaphylaxis occurred in 45 cases in 45 different patients (0.06 % of administration and 0.16 % of patients), all with onset within 30 min after administration. Thirty-one (69 %) had no risk factors for ADRs, including 14 (31 %) who had previously used the same ICM that caused anaphylaxis. Thirty-one patients (69 %) had a history of ICM use without any ADRs. Four patients (8.9 %) received oral steroid premedication. The only factor associated with anaphylaxis was the type of ICM, with an odds ratio (OR) of 6.8 (p < 0.001) for iomeprol with iopamidol as a reference. No significant differences in OR of anaphylaxis were found for patients' age, sex, or premedication.

CONCLUSION

The overall incidence of anaphylaxis due to ICM was very low. More than half of the cases had no risk factors for ADRs and had no ADRs on past ICM administration, although the ICM type was associated with a higher OR.

The value of CA125 in predicting acute complicated colonic diverticulitis

BACKGROUND

CA125 is a widely used serum marker for epithelial ovarian cancer which levels may also rise in benign conditions involving peritoneal irritation. We aimed to determine if serum CA125 levels can predict disease severity in patients presenting with acute diverticulitis.

METHODS

We conducted a single-center prospective observational study, analyzing CA125 serum levels in patients who presented to the emergency department with computerized tomography-proven acute left-sided colonic diverticulitis. Univariate, multivariate, and receiver operating characteristic (ROC) analyses were used to correlate CA125 serum levels at time of initial presentation with the primary outcome (complicated diverticulitis) and secondary clinical outcomes (need for urgent intervention, length of hospital stay (LOS) and readmission rates).

RESULTS

One hundred and fifty-one patients were enrolled between January 2018 and July 2020 (66.9% females, median age 61 years). Twenty-five patients (16.5%) presented with complicated diverticulitis. CA125 levels were significantly higher among patients with complicated (median: 16 (7-159) u/ml) vs. uncomplicated (8 (3-39) u/ml) diverticulitis (p < 0.001) and also correlated with the Hinchey severity class (p < 0.001). Higher CA125 levels upon admission were associated with a longer LOS and a greater chance to undergo invasive procedure during the hospitalization. In patients with a measurable intra-abdominal abscess (n = 24), CA125 levels were correlated with the size of the abscess (Spearman's r = 0.46, p = 0.02). On ROC analysis to predict complicated diverticulitis, the area under the curve (AUC) for CA125 (AUC = 0.82) was bigger than for the leukocyte count (AUC = 0.53), body temperature (AUC = 0.59), and neutrophil-lymphocyte ratio (AUC = 0.70) - all p values < 0.05. On multivariate analysis of factors available at presentation, CA125 was found to be the only independent predictor of complicated diverticulitis (OR 1.12 (95% CI 1.06-1.19), p < 0.001).

CONCLUSIONS

The results from this feasibility study suggest that CA125 may accurately discriminate between simple and complicated diverticulitis, meriting further prospective investigation.

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.

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.

Machine Learning Model Drift: Predicting Diagnostic Imaging Follow-Up as a Case Example

OBJECTIVE

Address model drift in a machine learning (ML) model for predicting diagnostic imaging follow-up using data augmentation with more recent data versus retraining new predictive models.

METHODS

This institutional review board-approved retrospective study was conducted January 1, 2016, to December 31, 2020, at a large academic institution. A previously trained ML model was trained on 1,000 radiology reports from 2016 (old data). An additional 1,385 randomly selected reports from 2019 to 2020 (new data) were annotated for follow-up recommendations and randomly divided into two sets: training (n = 900) and testing (n = 485). Support vector machine and random forest (RF) algorithms were constructed and trained using 900 new data reports plus old data (augmented data, new models) and using only new data (new data, new models). The 2016 baseline model was used as comparator as is and trained with augmented data. Recall was compared with baseline using McNemar's test.

RESULTS

Follow-up recommendations were contained in 11.3% of reports (157 or 1,385). The baseline model retrained with new data had precision = 0.83 and recall = 0.54; none significantly different from baseline. A new RF model trained with augmented data had significantly better recall versus the baseline model (0.80 versus 0.66, P = .04) and comparable precision (0.90 versus 0.86).

DISCUSSION

ML methods for monitoring follow-up recommendations in radiology reports suffer model drift over time. A newly developed RF model achieved better recall with comparable precision versus simply retraining a previously trained original model with augmented data. Thus, regularly assessing and updating these models is necessary using more recent historical data.

Lymphocyte Transformation Test for drug allergy detection: when does it work?

BACKGROUND

The lymphocyte transformation test (LTT) is an in vitro test system for the detection of a sensitization in the context of allergies to drugs. Its reported sensitivity varies largely and seems to be affected by different parameters. In review articles, the average LTT performance was often calculated by combining overall mean sensitivities of various published studies, but without considering different patient characteristics or varying patient numbers per publication.

OBJECTIVE

This meta-analysis aims to investigate the impact of different patient-specific and methodical parameters on the sensitivity of the LTT based on data on the level of the individual patient extracted from single studies.

METHODS

We performed an advanced literature search in Pubmed and screened the identified publications according to previously defined inclusion criteria. In total, individual patient data from 721 patients were extracted from 30 studies. Random-effects meta-regression analyses were performed.

RESULTS

The analysis indicate that the ELISA-based read-out is more sensitive compared to the classical radioactivity method (ELISA: 80% vs. radioactivity: 66%;p=0.084). Interestingly, DRESS/DHISS is associated with a higher probability of a positive LTT test result compared to other investigated clinical phenotypes ("DRESS/DHISS" vs. "bullous reaction"; OR: 2.52;p-value=0.003). Our analysis also revealed an impact of the time to testing period after the occurrence of the allergic event ("<2 weeks" vs. "2 weeks-2 months"; OR: 2.12;p-value=0.034).

CONCLUSION

The read-out method and relevant clinical parameters affect the sensitivity of the LTT. These findings are based on a meta-analysis providing a higher level of evidence than a single study or previous reviews not considering individual patient data.

Emergent Premedication for Contrast Allergy Prior to Endovascular Treatment of Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Management of contrast media allergies may lead to treatment delays in patients with acute ischemic stroke undergoing endovascular therapy. The optimal premedication strategy remains unclear. The aim of this report was to analyze our experience with emergent administration of premedication regimens before endovascular therapy.

MATERIALS AND METHODS

We retrospectively reviewed prospective data for all patients undergoing endovascular therapy from 2012 to 2019 at an academic comprehensive stroke center. Records of patients with documented contrast allergy were reviewed and analyzed. Data collected included stroke risk factors and characteristics, historical contrast reaction details, premedication regimens administered, and signs or symptoms of allergic reaction developing post-endovascular therapy. Hospital arrival time to endovascular therapy was compared with that in those who did not have a history of contrast allergy.

RESULTS

We analyzed 1521 patients undergoing endovascular therapy; 60 (4%) had documented contrast allergies and constituted the study cohort. The median age was 73 years (interquartile range, 66-81 years), and 65% were women. The median time from premedication to contrast was 24 minutes (interquartile range, 0-36 minutes). Forty-three patients (72%) proceeded directly to endovascular therapy; in 17 patients, the first contrast exposure was CTA. Time from hospital arrival to endovascular therapy was not slower for patients with documented allergies (96 versus 134 minutes, P = .32). No patients experienced a contrast media reaction.

CONCLUSIONS

In a single-institution cohort study of 60 consecutive patients with documented contrast allergies undergoing endovascular therapy with emergent premedication en route to (or in) the neuroangiography suite, no patients experienced allergic symptoms. This pragmatic approach may be safe for patients who have documented contrast media allergies.

Nonrenal Complications of Contrast Media

Injection of contrast media is the foundation of invasive and interventional cardiovascular practice. Iodine-based contrast was first used in the 1920s for urologic procedures and examinations. The initially used agents had high ionic and osmolar concentrations, which led to significant side effects, namely nausea, vomiting, and hypotension. Newer contrast agents had lower ionic concentrations and lower osmolarity. Modifications to the ionic structure and iodine content led to the development of ionic low-osmolar, nonionic low-osmolar, and nonionic iso-osmolar contrast media. Contemporary contrast agents are better tolerated and produce fewer major side effects.

Relationship between Lower Dose and Injection Speed of Iodinated Contrast Material for CT and Acute Hypersensitivity Reactions: An Observational Study

BackgroundThere are few data on the relationship between acute hypersensitivity reactions and the dose and injection rate of iodinated contrast material for CT.PurposeTo determine the relationship between lower dose and injection speed of iodinated contrast material for CT and the rate of acute hypersensitivity reactions.Materials and MethodsThis retrospective study included adults (age ≥18 years) undergoing nonionic iodinated contrast material-enhanced abdominal CT between August 2016 and January 2017 (control period) and between August 2017 and January 2018 (intervention period); all examinations were conducted in an outpatient setting. Compared with CT during the control period, CT during the intervention period involved a reduced dose of contrast material achieved by lowering the CT tube voltage. CT examinations in the control period were performed with 120 kVp, a contrast material dose of 2 mL/kg (maximum, 150 mL), and an injection speed of 3 or 4 mL/sec. CT examinations in the intervention period were performed with 100 kVp, a contrast material dose of 1.5 mL/kg (maximum, 130 mL), and an injection speed of 2.5 or 3 mL/sec. Per-examination rates of acute hypersensitivity reactions to iodinated contrast material were compared between the control and intervention periods with use of a multivariable Poisson regression model, the parameters of which were estimated by using generalized estimating equations with an independence correlation structure.ResultsA total of 21947 adults (mean age ± standard deviation, 59 years ± 12; 8797 women [40%]) underwent 25119 CT examinations during the control period; 23019 adults (mean age, 59 years ± 12; 9538 women [41%]) underwent 26491 CT examinations during the intervention period. The rate of acute hypersensitivity reactions was 1.42% (376 of 26491 examinations; 95% confidence interval [CI]: 1.28%, 1.57%) in the intervention period and 1.86% (468 of 25119 examinations; 95% CI: 1.70%, 2.04%) in the control period, with a multivariable-adjusted relative risk of 0.85 (95% CI: 0.74, 0.99; P = .03).ConclusionReduction in the dose and injection speed of iodinated contrast material for CT was associated with a lower rate of acute hypersensitivity reactions to iodinated contrast material.© RSNA, 2019Online supplemental material is available for this article.

Recognition and management of dermatologic complications from interventional radiology procedures

A variety of dermatologic complications can occur after interventional radiology procedures, including fluoroscopy-induced radiation dermatitis, thermal skin injury from tumor ablation, non-target embolization to the skin, allergic reactions related to interventional radiology procedures, and dermatitis and infections at catheter sites. Yet, interventional radiologists typically lack training in dermatology. This review focuses on recognition of dermatologic complications and introduces basic principles for management of these complications. By taking a more active role in the diagnosis, management, and follow-up of dermatologic complications, interventional radiologists can improve the care for patients suffering iatrogenic skin inury.

Practical administration of intravenous contrast media in children: screening, prophylaxis, administration and treatment of adverse reactions

Administration of intravenous contrast media to children is a routine practice at many clinical imaging centers, that can involve special considerations. In this paper, we provide practical information to facilitate optimal performance and oversight of this task. We provide targeted screening questions that can help to identify high-risk pediatric patients for both iodine-based and gadolinium-based intravenous contrast media administration. These include children at risk for allergic-like reactions, thyroid dysfunction, contrast-induced nephropathy, and nephrogenic systemic fibrosis. We make recommendations for addressing "yes" responses to screening questions using risk stratification schema that are specific to children. We also present criteria for selecting children for premedication prior to intravenous contrast administration, and suggest pediatric regimens. Additionally, we discuss practical nuances of intravenous contrast media administration to children and provide a quick-reference table of appropriate treatments with pediatric dosages for adverse contrast reactions.

Clinical decision support increases diagnostic yield of computed tomography for suspected pulmonary embolism

OBJECTIVE

Determine effects of evidence-based clinical decision support (CDS) on the use and yield of computed tomographic pulmonary angiography for suspected pulmonary embolism (CTPE) in Emergency Department (ED) patients.

METHODS

This multi-site prospective quality improvement intervention conducted in three urban EDs used a pre/post design. For ED patients aged 18+years with suspected PE, CTPE use and yield were compared 19months pre- and 32months post-implementation of CDS intervention based on the Wells criteria, provided at the time of CTPE order, deployed in April 2012. Primary outcome was the yield (percentage of studies positive for acute PE). Secondary outcome was utilization (number of studies/100 ED visits) of CTPE. Chi-square and statistical process control chart assessed pre- and post-intervention differences. An interrupted time series analysis was also performed.

RESULTS

Of 558,795 patients presenting October 2010-December 2014, 7987 (1.4%) underwent CTPE (mean age 52±17.5years, 66% female, 60.1% black); 34.7% of patients presented pre- and 65.3% post-CDS implementation. Overall CTPE diagnostic yield was 9.8% (779/7987 studies positive for PE). Yield increased a relative 30.8% after CDS implementation (8.1% vs. 10.6%; p=0.0003). There was no statistically significant change in CTPE utilization (1.4% pre- vs. 1.4% post-implementation; p=0.25). A statistical process control chart demonstrated immediate and sustained improvement in CTPE yield post-implementation. Interrupted time series analysis demonstrated the slope of PE findings versus time to be unchanged before and after the intervention (p=0.9). However, there was a trend that the intervention was associated with a 50% increased probability of PE finding (p=0.08), suggesting an immediate rather than gradual change after the intervention.

CONCLUSIONS

Implementing evidence-based CDS in the ED was associated with an immediate, significant and sustained increase in CTPE yield without a measurable decrease in CTPE utilization. Further studies will be needed to assess whether stronger interventions could further improve appropriate use of CTPE.

Is gender still a predisposing factor in contrast-media associated adverse drug reactions? A systematic review and meta-analysis of randomized trials and observational studies

OBJECTIVE

To evaluate the role of gender as a risk factor for developing contrast media-associated adverse drug reactions (CM-ADRs) by comparing the incidence of CM-ADR between male and female patients according to study design, ADR type, and computed tomography (CT) examination.

MATERIAL AND METHODS

We systematically searched three electronic databases for eligible studies. In the studies included (n=18), we assessed effect estimates of the relative incidence of CM-ADR, analysed by experimental design, ADR type and CT examination. This was calculated by using a random effects model if clinical conditions showed heterogeneity; otherwise, a fixed effects model was used.

RESULTS

We identified 10,776 patients administered CM. According to the designs, studies were classified into randomised controlled trials (RCTs) and observational studies. Results were as follows: risk ratio (RR)=1.07 (95% confidence interval (CI): 0.79-1.46, P=0.66) for RCTs, and RR=0.77 (95% CI: 0.58-1.04, P=0.09) for observational studies. The results of analysis according to ADR type and for undergoing CT demonstrated that the incidence of CM-ADR did not differ between males and females.

CONCLUSIONS

We found no significant difference in the incidence of CM-ADRs between male and female patients according to study design, ADR type, or CT examination. Future studies to determine why gender has shown different roles as a risk factor between CM-ADRs and non-CM ADRs are needed.

Clinical observation of adverse drug reactions to non-ionic iodinated contrast media in population with underlying diseases and risk factors

OBJECTIVE

To determine the adverse drug reaction (ADR) profile of non-ionic iodinated contrast media in populations with underlying diseases and risk factors and to provide guidance for more safe and rational use of iodinated contrast media (ICMs) in the clinic.

METHODS

Data from 120,822 cases who underwent enhanced CT examination in our hospital from January 2014 to March 2016 were collected. A standardized case report form was used for data collection and analysis.

RESULTS

The incidence of ADRs was 0.4% and 0.44% in patients with and without underlying diseases, respectively (p = 0.378). Risk factor analysis revealed that patients with asthma had the highest incidence of ADRs, followed by patients with cardiac insufficiency and patients who were aged had the lowest incidence. There was a low incidence of ADRs in patients under metformin (0.36%) and β-adrenaline receptor antagonist (0.20%) medication. The incidence was the highest in patients with previous ADRs to ICMs (7.17%) and the lowest in those with a history of ICM usage but no previous reactions (0.32%). ADRs were more common in patients at high risk at a higher injection dose (≥100 ml; p < 0.01) and speed (≥5 ml s^-1; p < 0.01).

CONCLUSION

The incidence of ADRs was extremely low in patients regardless of underlying diseases. Some high-risk factors have certain correlations with the occurrence of ADRs. Particular attention should be given to patients at high risk when performing enhanced CT examination. Advances in knowledge: The correlation between various risk factors and underlying diseases and ADRs was comprehensively analyzed in a large-scale population.

Hypersensitivity Reaction to Amiodarone in a Patient with a Previous Reaction to an lodinated Radiocontrast Agent

Objective:

To describe a case of a hypersensitivity reaction to oral amiodarone in a patient with a previous reaction to an iodinated radiocontrast agent.

Case Summary:

A 55-year-old man experienced facial urticaria after intraarterial injection of iohexol, an iodinated radiocontrast agent, during coronary angiography, which was successfully treated with intravenous hydrocortisone and promethazine. The procedure revealed significant triple vessel disease, and the patient subsequently underwent coronary artery bypass grafting in October 2006. Postoperatively, the patient experienced 2 episodes of fast atrial fibrillation, the first of which was treated successfully with intravenous amiodarone. The second episode resulted in the commencement of therapy with oral amiodarone 400 mg 3 times daily. Within one hour after the first dose, the patient experienced tip swelling and tingling, which was again treated with intravenous promethazine. Amiodarone was stopped; the patient remained in sinus rhythm and was discharged without further incident.

Discussion:

Amiodarone is a class III antiarrhythmic agent frequently used in the management of atrial fibrillation after cardiac surgery. The approved product information lists known hypersensitivity to iodine as a contraindication to its administration, but no other cases of amiodarone hypersensitivity in a patient with a previous reaction to an iodinated radiocontrast agent have been published, Conversely, it has been suggested that the drug may be safely used in such patients. The Naranjo probability scale supported a probable adverse reaction of hypersensitivity associated with amiodarone therapy in this patient.

Conclusions:

Prescribers should exercise caution in the administration of amiodarone to patients with a true, documented history of hypersensitivity to an iodinated compound.

The Incidence, Classification, and Management of Acute Adverse Reactions to the Low-Osmolar Iodinated Contrast Media Isovue and Ultravist in Contrast-Enhanced Computed Tomography Scanning

Some epidemiologic surveillance studies have recorded adverse drug reactions to radiocontrast agents. We aimed to investigate the incidence and management of acute adverse reactions (AARs) to Ultravist-370 and Isovue-370 in patients who underwent contrast-enhanced computed tomography (CT) scanning.Data from 137,473 patients were analyzed. They had undergone enhanced CT scanning with intravenous injection of Ultravist-370 or Isovue-370 during the period of January 1, 2006 to December 31, 2012 in our hospital. We investigated and classified AARs according to the American College of Radiology and the Chinese Society of Radiology (CSR) guidelines for iodinated contrast media. We analyzed risk factors for AARs and compared the AARs induced by Ultravist-370 and Isovue-370.Four hundred and twenty-eight (0.31%) patients experienced AARs, which included 330 (0.24%) patients with mild AARs, 82 (0.06%) patients with moderate AARs, and 16 (0.01%) patients with severe AARs (including 3 cases of cardiac arrest and one case of death). The incidence of AARs was higher with Ultravist-370 than with Isovue-370 (0.38% vs 0.24%, P < 0.001), but only for mild AARs (0.32% vs 0.16%, P < 0.001). Analyses on risk factors indicated that female patients (n = 221, 0.43%, P < 0.001), emergency patients (n = 11, 0.51%, P < 0.001), elderly patients aged 50 to 60 years (n = 135, 0.43%, P < 0.001), and patients who underwent coronary computed tomography angiography (CTA) (n = 55, 0.51%, P < 0.001) had a higher risk of AARs. Cutaneous manifestations (50.52%)-especially rash (59.74%)-were the most frequent mild AARs. Cardiovascular manifestations accounted for most moderate and severe AARs (62.91% and 48.28%, respectively). After proper management, the symptoms and signs of 96.5% of the AARs resolved within 24 hours without sequelae.Ultravist-370 and Isovue-370 are safe for patients undergoing enhanced CT scanning. The incidence of AARs is higher with Ultravist-370 than with Isovue-370, but this difference is limited only to the mild AARs. The incidence of AARs could be affected by multiple factors.

Intravenous Imaging Contrast Media Complications: The Basics That Every Clinician Needs to Know

Intravenous contrast is commonly used in noninvasive imaging procedures such as magnetic resonance imaging and computed tomography and can evaluate blood vessels and better characterize soft-tissue lesions. Although the incidence of adverse events after administration of contrast is low, it is important that clinicians and radiologists minimize risks and respond quickly and effectively when reactions occur. We will discuss a range of adverse events to iodinated and gadolinium-based contrast agents, including allergic-like reactions, nephrotoxicity, extravasation, and nephrogenic systemic fibrosis. We will review risk stratification for patients, as well as premedication and treatment of adverse events.

Deficits in allergy knowledge among physicians at academic medical centers

BACKGROUND

Allergic conditions have high prevalence in the general population. Misconceptions regarding the diagnosis and management of allergic disease among physicians can lead to suboptimal clinical care.

OBJECTIVE

To determine the extent of allergy-related knowledge deficits among physicians.

METHODS

Pediatric and internal medicine resident and attending physicians from 2 separate academic medical centers were asked to answer an anonymous electronic survey. Survey questions addressed 7 different allergy content areas.

RESULTS

Four hundred eight physicians completed surveys (23.9% response rate). Respondents had few correct answers (mean ± SD 1.91 ± 1.43). Pediatric respondents had a larger number of correct answers compared with medicine-trained physicians (P < .001). No individual answered every survey question correctly, and 50 respondents (12.3%) had no correct answer. Three hundred seventy-eight respondents (92.6%) were unable to provide correct answers for at least 50% of survey questions. Level of residency training and prior rotation through an allergy and immunology elective correlated with a larger number of correct responses (P < .01). Only 1 survey question had an overall correct response rate higher than 50% (n = 261, 64%). Correct response rate was lower than 30% for 7 of the 9 possible questions.

CONCLUSION

There are significant knowledge deficits in many areas of allergy-related content among pediatric and internal medicine physicians and across all levels of training and specialty. Given the prevalence of allergic conditions, the potential implications of a negative impact on clinical care are staggering.

Clinical observation of the adverse drug reactions caused by non-ionic iodinated contrast media: results from 109,255 cases who underwent enhanced CT examination in Chongqing, China

OBJECTIVE

To analyse the pattern and factors that influence the incidence of adverse drug reactions (ADRs) induced by non-ionic iodinated contrast media and to evaluate their safety profiles.

METHODS

Data from 109,255 cases who underwent enhanced CT examination from 1 January 2008 to 31 August 2013 were analysed. ADRs were classified according to the criteria issued by the American College of Radiology and the Chinese Society of Radiology.

RESULTS

A total of 375 (0.34%) patients had ADRs, including 281 mild (0.26%); 80 moderate (0.07%); and 14 severe (0.01%) ADRs; no death was found. 302 (80.53%) of the ADRs occurred within 15 min after examination. Patients aged 40-49 years (204 cases, 0.43%; p < 0.01) or who underwent coronary CT angiography (93 cases, 0.61%; p < 0.01) were at a higher risk of ADRs. Female patients (180 cases, 0.40%; p < 0.01) or outpatients had significantly higher incidence rates of ADRs. The symptoms and signs of most of the ADRs were resolved spontaneously within 24 h after appropriate treatment without sequelae.

CONCLUSION

The occurrence of ADRs is caused by the combined effects of multiple factors. The ADRs induced by non-ionic iodinated contrast media are mainly mild ones, while moderate or severe ADRs are relatively rare, suggesting that enhanced CT examination with non-ionic iodinated contrast media is highly safe, and severe adverse events will seldom occur under appropriate care.

ADVANCES IN KNOWLEDGE

The study included 109,255 patients enrolled in various types of enhanced CT examinations, which could reflect ADR conditions and regulations in Chinese population accurately and reliably.

Nonrenal Complications of Contrast Media

Nonrenal complications of contrast media are caused by chemotoxic or anaphylactoid reactions related to the contrast agent used. Chemotoxicity is mainly attributed to ionic concentration and osmolality. Anaphylactoid reactions are typically caused by direct activation of basophils, mast cells, and complement rather than an observable antigen-antibody interaction, and may be acute or delayed. History of an adverse reaction following prior exposure is the strongest predictor of a subsequent adverse reaction to contrast. Premedication regimens of corticosteroids or antihistamines can lower the risk of repeat adverse reactions. Treatment of anaphylactoid reactions depends on the severity of symptoms.

Comparison of the safety of seven iodinated contrast media

We aimed to determine the characteristic adverse events (AEs) of iodinated contrast media (IOCM) and to compare the safety profiles of different IOCM. This study used the database of AEs reports submitted by healthcare professionals from 15 Regional Pharmacovigilance Centers between June 24, 2009 and December 31, 2010 in Korea. All reports of IOCM, including iopromide, iohexol, iopamidol, iomeprol, ioversol, iobitridol and iodixanol, were analyzed. Safety profiles were compared between different IOCM at the system organ level using the proportional reporting ratio (PRR) and 95% confidence interval (95% CI). Among a total of 48,261 reports, 6,524 (13.5%) reports were related to the use of IOCM. Iopromide (45.5%), iohexol (16.9%), iopamidol (14.3%) and iomeprol (10.3%) were identified as frequently reported media. 'Platelet, bleeding & clotting disorders' (PRR, 29.6; 95%CI, 1.9-472.6) and 'urinary system disorders' (PRR, 22.3; 95% CI, 17.1-29.1) were more frequently reported for iodixanol than the other IOCM. In conclusion, the frequency of AEs by organ class was significantly different between individual media. These differences among different IOCM should be considered when selecting a medium among various IOCM and when monitoring patients during and after its use to ensure optimum usage and patient safety.

Influence of MRI contrast media on histamine release from mast cells

Background:

Mast cells, owing to diversity of secreted mediators, play a crucial role in the regulation of inflammatory response. Together with basophils, mast cells constitute a central pathogenetic element of anaphylactic (IgE-dependent) and anaphylactoid (IgE-independent) reactions. In severe cases, generalized degranulation of mast cells may cause symptoms of anaphylactic shock. The influence of the classical, iodine-based contrast media on mastocyte degranulation has been fully described. Our objective was to determine the influence of the gadolinium-based MRI contrast media on histamine release from mast cells and to compare the activity of ionic and non-ionic preparations of contrast media.

Material/Methods:

To determine the intensity of mast cell degranulation, we used an experimental model based on mastocytes isolated from rat peritoneal fluid. Purified suspensions of mast cells were incubated with various concentrations of Gd-DTPA and Gd-DTPA-BMA, and solutions of PEG 600 which served as a non-toxic osmotic stimulus. The intensity of mast cell activation was presented as mean percentage of histamine released from cells after incubation.

Results/Conclusions:

The obtained results demonstrate that both ionic and non-ionic preparations of the MRI contrast media are able to induce mast cell degranulation in vitro. It was also proved that the non-ionic MRI contrast media stimulate mast cells markedly more weakly than ionic contrast media at identical concentration. The aforementioned results may suggest a more profitable safety profile of the non-ionic contrast preparations. We may also conclude that triggering of mast cell degranulation after incubation with the solutions of MRI contrast media results from non-specific osmotic stimulation and direct toxicity of free ionic residues.

Previous iodinated contrast anaphylaxis in blunt abdominal trauma: management options

A 34-year-old man presented with significant intra-abdominal and orthopaedic injuries following a high-speed motorbike crash. The man had a history of an anaphylactic reaction to iodine. As a result, the gold standard CT of the abdomen with contrast was unable to be performed to ascertain the exact nature of the intra-abdominal injuries. After stabilisation, an MRI of the abdomen was performed which localised the injuries. The previous contrast anaphylaxis delayed full assessment of the patient and subsequent management. This case discusses the current literature and the management guidelines in a patient with previous anaphylaxis to contrast.

Surveillance of contrast-media-induced hypersensitivity reactions using signals from an electronic medical recording system

BACKGROUND

Contrast-media (CM) hypersensitivity is a well-known adverse drug reaction. Surveillance of adverse drug reactions usually depends on spontaneous reports. However, the rate of spontaneous reports is low. Recent progress in information technology enables the electronic search on signals of adverse drug reactions from electronic medical recording (EMR) systems.

OBJECTIVES

To analyze the incidence and clinical characteristics of CM hypersensitivity using an EMR-based surveillance system.

METHODS

The surveillance system used signals from standardized terms within the international classification of nursing practice terms that can indicate symptoms of CM hypersensitivity and from the order codes for procedures that used contrast media, antihistamine, and epinephrine. The search strategy was validated by allergists comparing the electronic search strategy versus manually reviewing medical charts over one month. The main study covered for one year period.

RESULTS

Detection rate of the electronic search method was 0.9% (7/759), while that of the manual search method was 0.8% (6/759). EMR-based electronic search method was highly efficient: reduced the charts that needed to be reviewed by 96% (28/759). The sensitivity of electronic screening was 66.7%, specificity was 99.6%, and the negative predictive value was 99.7%. CM hypersensitivity reactions were noted in 266 among 12,483 cases (2.1%). Urticaria was the most frequent symptom (74.4%). CT was the most frequent procedure (3.6%) that induced CM hypersensitivity.

CONCLUSION

A surveillance system using EMR may be a useful tool in the study of drug hypersensitivity epidemiology and may be used in an adverse drug reaction alarm system and as a clinical, decision making support system.

A clinical study of cutaneous adverse reactions to nonionic contrast media in Korea

Background

The use of intravenous contrast media (CM) has increased for the diagnosis of several diseases. The newly developed low osmolar nonionic contrast agents cause significantly decreased adverse reactions than the higher osmolar ones. However, adverse reactions may still occur, ranging in severity from minor side effects to severe complications. However, there have been few reports about cutaneous adverse reactions (CARs) to nonionic monomer CM.

Objective

The purpose of this study was to evaluate clinical features of CAR to intravenous nonionic monomer CM.

Methods

A total 47,338 examinees underwent intravenous iodinated contrast-enhanced computed tomography scan using nonionic monomer CM. Among the adverse reactions to the CM, we divided them into cutaneous or noncutaneous and immediate (<1 hr) or late (≥1 hr) adverse reactions.

Results

Adverse reactions were noted in 62 cases out of the total 47,338 cases; 50 cases (80.7%) were categorized CARs. Among them, there were 24 male and 26 female patients. There was no significant difference between the sexes, and CARs occurred in all age groups. The highest occurrence was in the age range of 50~59 years. CARs included urticaria (78%), angioedema (10%), maculopapular rash (8%), erythema (2%), and pruritus without rash (2%). Immediate reactions were 92% (46 cases), while late reactions were 8% (4 cases).

Conclusion

CARs to nonionic monomer CM accounted for most of the adverse reactions (80.7%) and urticaria was the most common.

Chemically oversulfated glycosaminoglycans are potent modulators of contact system activation and different cell signaling pathways

Contaminated heparin was associated with adverse reactions by activating the contact system. Chemically oversulfated/modified glycosaminoglycans (GAGs) consisting of heparan sulfate, dermatan sulfate, and chondroitin sulfate have been identified as heparin contaminants. Current studies demonstrated that each component of oversulfated GAGs was comparable with oversulfated chondroitin sulfate in activating the contact system. By testing a series of unrelated negatively charged compounds, we found that the contact system recognized negative charges rather than specific chemical structures. We further tested how oversulfated GAGs and contaminated heparins affect different cell signaling pathways. Our data showed that chemically oversulfated GAGs and contaminated heparin had higher activity than the parent compounds and authentic heparin, indicative of sulfation-dominant and GAG sequence-dependent activities in BaF cell-based models of fibroblast growth factor/fibroblast growth factor receptor, glial cell line-derived neurotrophic factor/c-Ret, and hepatocyte growth factor/c-Met signaling. In summary, these data indicate that contaminated heparins intended for blood anticoagulation not only activated the contact system but also modified different GAG-dependent cell signaling pathways.

Nonionic iodinated intravenous contrast material-related reactions: incidence in large urban children's hospital--retrospective analysis of data in 12,494 patients

PURPOSE

To examine the incidence and severity of nonionic intravenous contrast material reactions in a large pediatric patient population.

MATERIALS AND METHODS

Electronic records on all consecutive patients at a tertiary care pediatric hospital who received ioversol contrast material over a 7-year period for computed tomographic or excretory urographic studies were reviewed, yielding individual contrast material injection events in 12,494 patients up to 21 years of age. There were 6600 male patients and 5894 female patients. Contrast material reactions were categorized as mild, moderate, or severe according to American College of Radiology guidelines. Logistic regression analysis was performed to evaluate effects of age, sex, season, and study year on the presence of an intravenous contrast material reaction.

RESULTS

There were 57 adverse events related to nonionic iodinated intravenous contrast material in 12,494 consecutive pediatric and young adult patients. Incidence of a contrast material reaction was 0.46% (57 of 12,494), or one in 200 patients. Incidence of a type I (mild) contrast material reaction was 0.38% (47 of 12,494), or one in 250 patients. Incidence of a type II (moderate) reaction was 0.08% (10 of 12,494), or one in 1000 patients. There were no severe (type III) reactions. The average age of patients with a contrast material reaction (12.9 years +/- 4.3 [standard deviation]) was 3.4 years older (P < .001) than the average age of all patients in the study (9.5 years +/- 5.9). There was a significant relationship between patient age and incidence of contrast material reaction per 1000 studies (P = .003), independent of sex, season, and year of study.

CONCLUSION

Adverse reactions to intravenous administration of a nonionic contrast material (ioversol) are rare in children and increase in frequency with advancing age. The great majority of reactions in children are mild.

Complications and pitfalls of lumbar interlaminar and transforaminal epidural injections

Lumbar interlaminar and transforaminal epidural injections are used in the treatment of lumbar radicular pain and other lumbar spinal pain syndromes. Complications from these procedures arise from needle placement and the administration of medication. Potential risks include infection, hematoma, intravascular injection of medication, direct nerve trauma, subdural injection of medication, air embolism, disc entry, urinary retention, radiation exposure, and hypersensitivity reactions. The objective of this article is to review the complications of lumbar interlaminar and transforaminal epidural injections and discuss the potential pitfalls related to these procedures. We performed a comprehensive literature review through a Medline search for relevant case reports, clinical trials, and review articles. Complications from lumbar epidural injections are extremely rare. Most if not all complications can be avoided by careful technique with accurate needle placement, sterile precautions, and a thorough understanding of the relevant anatomy and contrast patterns on fluoroscopic imaging.

Safety aspects of iodinated contrast media related to their physicochemical properties: a pharmacoepidemiology study in two Tuscany hospitals

BACKGROUND

More than 380,000 angiographic procedures are performed every year in Italian hospitals, with an increase rate of 8% per year. Although contrast media (CM) are considered relatively safe, adverse drug reactions (ADRs) remain an important issue.

OBJECTIVES

The objective of this study was to quantify the incidence of immediate and delayed nonrenal ADRs to iodinated CM in an Italian cohort and to evaluate whether their different physicochemical properties are able to affect the incidence of immediate or delayed ADRs.

METHODS

A prospective intensive monitoring study was conducted on a cohort of patients undergoing radiodiagnostic procedures with iodinated CM enrolled in two hospitals in Tuscany, Italy. To evaluate both immediate (within 1 h after CM administration) and delayed (>1 h to 1 week after CM administration) ADRs to CM, two questionnaires were administered. Adverse events (AEs) were analyzed to check the causality assessment between CM and ADR. If more than one symptom occurred in the same patient, they were treated as a single event.

RESULTS

One thousand five hundred and fourteen subjects who were exposed to iodinated CM completed the questionnaires. Mean age [standard deviation (SD)] was 65.4 (13.3) years, and 57.9% were male patients. A total of 178 [11.8%; 95% confidence interval (CI) 10.1-13.4] ADRs were reported. Thirty-four (2.2%; 1.5-3.1) and 144 (9.5%; 8.0-11.1) developed immediate and delayed ADRs, respectively. Both types of ADRs were experienced by six subjects (0.4%; 0.1-0.8). One hundred and seventy-six cases (98.8%; 96.0-99.8) were classified as possible and two (1.1%; 0.1-3.9) as probable ADRs. Monomeric low-osmolal (iopromide, iomeprol, iobitridol) and dimeric iso-osmolal (iodixanol) groups mainly reported delayed allergy-like ADRs of mild severity. Only one immediate reaction was severe. Multivariate analysis confirmed a higher risk of immediate reactions occurring for monomeric CM (OR 4.3; 95% CI 1.2-15.7), whereas the risk of delayed ADRs was significantly higher for the dimeric group (OR 1.8; 1.1-2.5).

CONCLUSIONS

Monomeric CM were more frequently involved in immediate ADRs, whereas dimeric CM were involved in delayed reactions. Although severe life-threatening ADRs to CM were confirmed to be rare, due to the large use of these drugs, they still retain clinical and epidemiological significance.