Reactions to radiocontrast material. Anaphylactoid events in radiology

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.

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.

Evaluating pharmacists' knowledge, attitude, and practices toward amiodarone cross-reactivity with iodine: a cross-sectional pilot study

Introduction

Iodine is a vital mineral of the human body that acts by maintaining the health of the thyroid gland. Research has shown that iodine-rich food allergy (i.e., seafood allergy) is not caused by iodine itself; instead, it is caused by other proteins including tropomyosin and parvalbumin in shellfish and fish, respectively. Amiodarone is a commonly used antiarrhythmic agent containing a significant amount of iodine.

Objective

This study's objective was to assess pharmacists' knowledge, attitude, and practices toward the misconception of iodine allergy and the cross-reactivity with amiodarone.

Methods

In February 2020, a cross-sectional study was conducted by sending out an online survey to three pharmaceutical organizations (Saudi Pharmaceutical Society, Kuwait Pharmaceutical Association, and Oman Pharmaceutical Society). Additionally, an electronic questionnaire was administered to pharmacists attending the Dubai International Pharmaceuticals and Technologies Conference and Exhibition 2020 (DUPHAT). Chi-square or Fisher's exact test, when appropriate, were used to compare categorical variables. The statistical analyses were carried out using SPSS software.

Results

Data were collected from 66 respondents. However, only 61 (92.4%) were included in the final analysis following the exclusion of incomplete responses. The mean age of participants was 35 ± 8.48 years. The majority of participants did not have the Board of Pharmacy Specialties Certification (54.1%). Moreover, (41%) of participants licensed as pharmacists with more than 10 years of initial pharmacy licensure. Forty-three (70.5%) of participants had the misconception that iodine allergy should be considered before amiodarone administration, 20/32 (62.5%) of whom considered iodine allergy alone thought that premedication with corticosteroids and/or antihistamines is necessary. Concerning iodine allergy and amiodarone use, there was no significant difference in knowledge between the pharmacists who have board certification and those who did not.

Conclusion

Pharmacists' misconception concerning iodine allergy and cross-reactivity with amiodarone was evident. Implementation of educational programs targeting pharmacists is necessary to correct these misconceptions.

Doctor I Have an Iodine Allergy

Ophthalmologists frequently face patients who refuse asepsis protocols involving povidone-iodine (PI) due to claims of an allergy to iodine. Such patients usually base this claim on previous reactions to shellfish consumption or to imaging procedures that used iodine-based contrast agents. Allergy to iodine, however, is biologically impossible, and iodine deficiency causes severe developmental problems, including mental retardation. Furthermore, shellfish allergy is due to tropomyosins in muscle tissue, and reactions to intravascular contrast dyes are due to hyperosmolar solutions; neither “allergy” is due to iodine. PI, which contains 9–12% iodine, is the preferred antiseptic for ophthalmic procedures. Experience shows that PI can be administered safely to patients claiming iodine allergy. True allergy to PI is rare and, if indicated, skin patch testing can be performed prior to surgery. Patients who react adversely to highly concentrated (5–10%) PI usually experience toxicity to the corneal and conjunctival epithelium after topical administration. Dilute (0.1–0.25%) PI kills microbes quicker than higher concentrations but for shorter periods of time because the total dose of iodine is smaller. Repeated administration (every 20–30 s) of dilute PI effectively kills microbes for as long as necessary with little risk of epithelial toxicity.

Radiocontrast Media Hypersensitivity Reactions in Children

Hypersensitivity reactions to radiocontrast media seem to be rare in children. Furthermore, the use of radiocontrast media in children remains quite safe in terms of the severity of reactions. Since pediatric guidelines are lacking, the diagnostic workup employed in adults could be adapted to children, taking into account that results have not yet been validated in this age group. Specific protocols for risk stratification and management of severe reactions have been proposed so far.

Contrast Extravasation using Power Injectors for Contrast-Enhanced Computed Tomography in Children: Frequency and Injury Severity

PURPOSE

To evaluate the safety of power injectors for contrast-enhanced computed tomography (CT) in children, namely: the prevalence and injury severity of contrast extravasations related to power injectors and the factors associated with these events.

METHODS

The need to obtain informed consent was waived for this HIPAA-compliant and IRB approved retrospective study. Around 2429 contrast-enhanced CT performed with a power injector were identified during a 3-year period. Data collected included patient demographic, power injector, and contrast agent information. The patients' symptoms, severity of injury and treatment with contrast extravasation were recorded. Around 1496 cases (823 boys, 673 girls) were included in the analysis. Independent-sample t test and Chi-square were used. For a sub-analysis using the extravasation cases, nonparametric tests were used.

RESULTS

The mean age was 9.5 ± 6.1 years. The most common access site, catheter site, and contrast agent used were the antecubital fossa, 22 gauge and Iohexol. The mean peak pressure was 68.9 ± 62.3 psi and the flow rate was 1.7 ± 0.9 mL/s. Eighteen cases of contrast extravasation were identified with a mean age of 11.2 ± 6.2 years. There were seven mild, six moderate, and five severe. Cases with extravasation had significantly higher peak pressure (p < 0.001) and flow rate (p < 0.001) compared to those without extravasation. Patients who received Iohexol-350 had significantly more contrast extravasation compared to those who used Iohexol-300 (p = 0.03). However, after post-hoc correction, only peak pressure (p < 0.01) and flow rate (p = 0.01) remained significant.

CONCLUSION

The use of power injectors in children undergoing contrast-enhanced CT is associated with a low rate of extravasation and of long-term injury.

Safety of Noncontrast Imaging-Guided Deep Brain Stimulation Electrode Placement in Parkinson Disease

BACKGROUND

Deep brain stimulation (DBS) is considered standard of care for the treatment of medically refractory Parkinson disease (PD). The placement of brain electrodes is performed using contrast imaging to enhance blood vessel identification during stereotactic planning. We present our experience with a series of patients implanted using noncontrast imaging.

METHODS

All cases of DBS surgery for PD performed between 2012 and 2018 with noncontrast imaging were retrospectively reviewed. Clinical features, postoperative imaging, and complications were analyzed.

RESULTS

A total of 287 deep-seated electrodes were implanted in 152 patients. Leads were placed at the subthalamic nucleus and globus pallidus internus in 258 and 29 hemispheres, respectively. We identified 2 cases of intracranial hemorrhage (0.7%).

CONCLUSIONS

DBS lead placement can be performed without the use of intravenous contrast with a postoperative intracranial hemorrhage rate comparable with other reported series.

Premedication for Iodinated Contrast Media Induced Immediate Hypersensitivity Reactions

Purpose of the review

Premedication using antihistamines and/or corticosteroids has been widely used to prevent reoccurrence of immediate hypersensitivity reactions (iHR) after iodinated contrast media (ICM). However, efficacy has been debated, especially in high-risk patients. Novel findings on the role and risks of premedication and preventive strategies are summarized.

Recent findings

The rate and severity of iHR occurring despite premedication indicate that premedication is not a panacea and the intensity usually reflects that of the initial reaction. Next, the number needed to treat (NNT) to prevent one serious ICM-mediated event using corticosteroid-based premedication is high and associated with a diagnostic delay. Randomly changing the ICM has been suggested as an additional preventive measure, whilst others used a skin test–based approach to identify a subgroup of ICM allergic patients and negative skin test–based alternatives with a high negative predictive value.

Summary

Growing evidence indicates the need to discriminate between non-allergic iHR that are most likely non-obligatory and susceptible to premedication, and rare type I allergic iHR that can be identified using skin testing, especially in those with a severe iHR. Although premedication reduces reoccurrence of mild iHR, it is not always efficacious and should be balanced against side effects, a high NNT and an uncertain efficacy physicians should not blindly rely on. Future work should evaluate combined approaches of an allergy-driven ICM selection and endotype-driven premedication regimens in patients with non-allergic iHR.

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.

Evaluation of nephroprotection of silymarin on contrast-induced nephropathy in liver cirrhosis patients: A population-based cohort study

Recent findings from an animal experiment suggest a modest association between silymarin and decreased risk of contrast-induced nephropathy. However, the relationship between silymarin and contrast-induced nephropathy in patients with liver cirrhosis remains unclear.From 1997 to 2007, we identified 3019 patients with liver cirrhosis who were administered silymarin and matched them with 3019 patients with liver cirrhosis who were not administered silymarin. Each patient was followed up for a minimum of 4 years. After adjusting for age, gender, hepatitis B, hepatitis C, alcoholic hepatitis, and Charlson comorbidity index, we considered death occurrence and used the Fine and Gray regression models to calculate subdistribution hazard ratios (sHRs) for contrast-induced nephropathy. Sensitivity analyses were also performed using the same model on the subgroups classified by comorbidity.Using the Fine and Gray regression models and with death as the competing risk, we observed that sHR for contrast-induced nephropathy was 0.94-fold higher in the silymarin cohort than in the nonsilymarin cohort (95% confidence interval = 0.61-1.47, P = .791). On the basis of sensitivity analyses results classified by comorbidity, a nonsignificant decrease in risk of contrast-induced nephropathy was found.Silymarin shows no nephron-protective positive effects on contrast-induced nephropathy. Silymarin did not play a nephron-protective role according to Longitudinal Health Insurance Database of Taiwan. Clinical trials are necessary to further assess the nephron-protective effects of silymarin of contrast-induced nephropathy.

Immediate Hypersensitivity to Contrast Agents: The French 5-year CIRTACI Study

BACKGROUND

Iodinated and gadolinium-based contrast media (ICM; GBCM) induce immediate hypersensitivity (IH) reactions. Differentiating allergic from non-allergic IH is crucial; allergy contraindicates the culprit agent for life. We studied frequency of allergic IH among ICM or GBCM reactors.

METHODS

Patients were recruited in 31 hospitals between 2005 and 2009. Clinical symptoms, plasma histamine and tryptase concentrations and skin tests were recorded. Allergic IH was diagnosed by intradermal tests (IDT) with the culprit CM diluted 1:10, "potentially allergic" IH by positive IDT with pure CM, and non-allergic IH by negative IDT.

FINDINGS

Among 245 skin-tested patients (ICM = 209; GBCM = 36), allergic IH to ICM was identified in 41 (19.6%) and to GBCM in 10 (27.8%). Skin cross-reactivity was observed in 11 patients with ICM (26.8%) and 5 with GBCM (50%). Allergy frequency increased with clinical severity and histamine and tryptase concentrations (p < 0.0001). Cardiovascular signs were strongly associated with allergy. Non-allergic IH was observed in 152 patients (62%) (ICM:134; GBCM:18). Severity grade was lower (p < 0.0001) and reaction delay longer (11.6 vs 5.6 min; p < 0.001). Potentially allergic IH was diagnosed in 42 patients (17.1%) (ICM:34; GBCM:8). The delay, severity grade, and mediator release were intermediate between the two other groups.

INTERPRETATION

Allergic IH accounted for < 10% of cutaneous reactions, and > 50% of life-threatening ones. GBCM and ICM triggered comparable IH reactions in frequency and severity. Cross-reactivity was frequent, especially for GBCM. We propose considering skin testing with pure contrast agent, as it is more sensitive than the usual 1:10 dilution criteria.

Managing Adverse Reactions to Contrast Agents

Adverse reactions to iodinated and gadolinium-based contrast agents occur at an incidence of less than 1%. Although the exact pathophysiologic mechanisms are not completely understood, the treatment regimens are well accepted. Skin testing may be helpful in patients with a history of severe allergiclike reaction to aid in the selection of alternative contrast agents. Premedication should only be used for a history of allergiclike reaction. Imaging team members should be familiar with signs and symptoms of contrast reactions to allow for prompt assessment and treatment. A plan of action should be in place for contrast reactions and rehearsed regularly.

The Use of Contrast in Caudal Epidural Injections under Image Intensifier Guidance: Is It Necessary?

Background

We investigated the value of using contrast as an additional aid to confirm the accuracy of needle placement for caudal epidural injections under intraoperative image intensifier guidance.

Methods

A total of 252 consecutive patients were included in this study. Their mean age was 46.7 years (range, 32 to 76 years). There were 133 males (53%) and 119 females (47%) over a 12-month period.

Results

Of the 252 consecutive procedures, the contrast enhanced image intensifier confirmed accurate needle placement on first attempt in 252 cases (100%). Needle resiting following the infiltration of contrast was required in 0 case.

Conclusions

The results from this study demonstrate that a surgeon beyond the learning curve can accurately place caudal epidural injections using image intensification only, without the use of contrast.

Basophil Reactivity as Biomarker in Immediate Drug Hypersensitivity Reactions-Potential and Limitations

Immediate drug hypersensitivity reactions (DHRs) resemble typical immunoglobulin E (IgE)-mediated symptoms. Clinical manifestations range from local skin reactions, gastrointestinal and/or respiratory symptoms to severe systemic involvement with potential fatal outcome. Depending on the substance group of the eliciting drug the correct diagnosis is a major challenge. Skin testing and in vitro diagnostics are often unreliable and not reproducible. The involvement of drug-specific IgE is questionable in many cases. The culprit substance (parent drug or metabolite) and potential cross-reacting compounds are difficult to identify, patient history and drug provocation testing often remain the only means for diagnosis. Hence, several groups proposed basophil activation test (BAT) for the diagnosis of immediate DHRs as basophils are well-known effector cells in allergic reactions. However, the usefulness of BAT in immediate DHRs is highly variable and dependent on the drug itself plus its capacity to spontaneously conjugate to serum proteins. Stimulation with pure solutions of the parent drug or metabolites thereof vs. drug-protein conjugates may influence sensitivity and specificity of the test. We thus, reviewed the available literature about the use of BAT for diagnosing immediate DHRs against drug classes such as antibiotics, radio contrast media, neuromuscular blocking agents, non-steroidal anti-inflammatory drugs, and biologicals. Influencing factors like the selection of stimulants or of the identification and activation markers, the stimulation protocol, gating strategies, and cut-off definition are addressed in this overview on BAT performance. The overall aim is to evaluate the suitability of BAT as biomarker for the diagnosis of immediate drug-induced hypersensitivity reactions.

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.

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

BACKGROUND

Patients with a previous history of hypersensitivity reaction (HSR) to iodinated contrast media (ICM) are at high risk of the development of HSR to ICM. Many studies have tried to evaluate the diagnostic potential of skin tests in this population but have not yet reached a common conclusion. We investigated the role of skin tests in patients with HSR to ICM in terms of positive rate, cross-reactivity rate, and tolerability to skin test-negative ICM according to the type of HSR.

METHODS

We performed literature searches of the MEDLINE and EMBASE databases and included studies where skin tests were performed in patients with HSR to ICM, with extractable outcomes. Outcomes were pooled using a random-effects model.

RESULTS

Twenty-one studies were included. Pooled per-patient positive rates of skin tests were 17% (95% CI, 10-26%) in patients with immediate HSR, and up to 52% (95% CI, 31-72%) when confined to severe immediate HSR. Among patients with nonimmediate HSR, the positive rate was 26% (95% CI, 15-41%). The pooled per-patient cross-reactivity rate was higher in nonimmediate HSR (68%; 95% CI, 48-83%) than that in immediate HSR (39%; 95% CI, 29-50%). Median per-test cross-reactivity rates between pairs of ICM were 7% (IQR, 6-9%) in immediate HSR and 38% (IQR, 22-51%) in nonimmediate HSR. Pooled per-patient recurrence rates of HSR to skin test-negative ICM were 7% (95% CI, 4-14%) in immediate HSR and 35% (95% CI, 19-55%) in nonimmediate HSR.

CONCLUSION

Skin tests may be helpful in diagnosing and managing patients with HSR to ICM, especially in patients with severe immediate HSR.

Examination of patients suspected as having hypersensitivity to iodinated contrast media with leukocyte migration test

In vivo tests may be used for the diagnosis of allergy to iodinated contrast media (ICM); however, the tests do not provide definitive diagnosis and are associated with risks for patients. Diagnoses based on in vitro tests are limited, and there are almost no relevant studies. Herein, the authors examined involvement of allergic reaction from a multilateral standpoint in 39 patients suspected of having ICM allergies using leukocyte migration test (LMT). The positive rate of LMT was 44%. A comparison with the positive rate of LMT in drugs other than ICM (74%) indicated 30% difference, which was significantly low value, suggesting that there is poor involvement of these drugs in the allergic reaction. In LMT positives, 76% of hypersensitivity reactions were skin rash mainly erythema, and 18% was anaphylactic reactions. Cases considered as non-immediate hypersensitivity accounted for about 4 times as many as immediate-type hypersensitivity. In examination of relevancy between a history of drugs or food allergies, the incidence of ICM allergies was 35%. There is a high possibility that these adverse reactions were caused by pseudoallergy to drug. It was suggested that most hypersensitivity reactions were skin rash related to non-immediate hypersensitivity, and approximately 20% of the reaction was immediate anaphylactic reaction. Therefore attention should be paid not only to immediate-type hypersensitivity but also delayed reactions. Moreover, it was considered that patients with past history of drug or food allergies have a high potential for manifestation of the reactions.

Does the time between CT scan and chemotherapy increase the risk of acute adverse reactions to iodinated contrast media in cancer patients?

Background

Cancer patients undergo routine computed-tomography (CT) scans and, therefore, iodinated contrast media (ICM) administration. It is not known whether a time-dependent correlation exists between chemotherapy administration, contrast enhanced CT and onset of acute ICM-related adverse reactions (ARs).

Methods

All consecutive contrast-enhanced CTs performed from 1 January 2010 to 31 December 2012 within 30 days of the last chemotherapy administration were retrospectively reviewed. Episodes of acute ICM-related ARs were reported to the pharmacovigilance officer. We analyzed time to CT evaluation calculated as the time elapsed from the date of the CT performed to the date of the last chemotherapy administration. Patients were classified into 4 groups based on the antineoplastic treatment: platinum-based, taxane-based, platinum plus taxane and other group.

Results

Out of 10,472 contrast-enhanced CTs performed, 3,945 carried out on 1,878 patients were considered for the study. Forty acute ICM-related ARs (1.01%; 95% CI, 0.70-1.33) were reported. No differences were seen among immediate (within 10 days of the last chemotherapy administration), early (11–20 days) and delayed (21–30 days) CTs. Median time to CT in patients who experienced an acute ICM-related AR by treatment group was not statistically different: 20 days (range 6–30), 17 days (range 5–22), 13 days (range 8–17), 13 days (range (2–29) for the platinum, taxane, platinum plus taxane and other group, respectively (P =0.251).

Conclusions

Our results did not reveal any correlation between time to CT and risk of acute ICM-related ARs in cancer patients.

Taxanes as a risk factor for acute adverse reactions to iodinated contrast media in cancer patients

BACKGROUND

The impact of cytotoxic agents on the risk of acute allergy-like adverse reactions (ARs) to intravenous iodinated contrast media (ICM) injections is unknown.

METHODS

We retrospectively reviewed 13,565 computed tomography (CT) scans performed in a consecutive cohort of cancer patients from January 1, 2010 to December 31, 2012. Episodes of acute ICM-related ARs were reported to the pharmacovigilance officer. The following matched comparisons were made: tax code, gender, primary tumor, antineoplastic therapy, and date of last cycle. Concomitant antineoplastic treatment was classified into five groups: platinum, taxane, platinum plus taxane, other, and no treatment group (no therapy had been administered in the previous 24 months). Logistic regression was used to estimate odds ratio (OR) and 95% confidence interval (CI) to evaluate the risk of acute ICM-related ARs.

RESULTS

Of 10,472 contrast-enhanced CT scans, 97 (0.93%; 95% CI: 0.74-1.11) ICM-related ARs were reported, 11 of which (0.1%) were severe, including one fatality. The overall incidence was significantly higher in patients aged <65 years (p = .0062) and in the platinum plus taxane and taxane groups (p = .007), whereas no correlation was found with gender, number of previous CT scans, site of disease, or treatment setting. Multivariate analysis confirmed an increased risk for patients aged <65 years (OR: 1.73; 95% CI: 1.14-2.63) and for the taxane group (in comparison with the no treatment group; OR: 2.06; 95% CI: 1.02-4.16).

CONCLUSION

Among cancer patients, concomitant treatment with taxanes and younger age would seem to be risk factors for ICM-related ARs.

Practice patterns for the use of iodinated i.v. contrast media for pediatric CT studies: a survey of the Society for Pediatric Radiology

OBJECTIVE

There are limited data available on the use of i.v. contrast media for CT studies in the pediatric population. The purpose of this study is to determine the practice patterns of i.v. contrast media usage for pediatric CT by members of the Society for Pediatric Radiology (SPR).

MATERIALS AND METHODS

SPR members were surveyed regarding the use of i.v. contrast media for pediatric CT studies. Questions pertained to information required before administering i.v. contrast media, types of central catheters for injecting i.v. contrast media, injection rates based on angiocatheter size and study type, and management of i.v. contrast media extravasation.

RESULTS

The response rate of 6% (88/1545) represented practice patterns of 26% (401/1545) of the SPR membership. Most respondents thought the following clinical information was mandatory before i.v. contrast media administration: allergy to i.v. contrast media (97%), renal insufficiency (97%), current metformin use (72%), significant allergies (61%), diabetes (54%), and asthma (52%). Most administered i.v. contrast media through nonimplanted central venous catheters (78%), implanted venous ports (78%), and peripherally inserted central catheters (72%). The most common maximum i.v. contrast media injection rates were 5.0 mL/s or greater for a 16-gauge angiocatheter, 4.0 mL/s for an 18-gauge angiocatheter, 3.0 mL/s for a 20-gauge angiocatheter, and 2.0 mL/s for a 22-gauge angiocatheter. For soft-tissue extravasation of i.v. contrast media, 95% elevate the affected extremity, 76% use ice, and 45% use heat.

CONCLUSION

The results of this survey illustrate the collective opinion of a subset of SPR members relating to the use of i.v. contrast media in pediatric CT, providing guidelines for clinical histories needed before i.v. contrast media, maximum i.v. contrast injection rates for standard angiocatheters, contrast media injection rates for specific CT studies, and management of i.v. contrast media soft-tissue extravasation.

Evaluation of adverse reactions to contrast media in the hospital

OBJECTIVE

To determine and analyse the characteristics of contrast media adverse reactions (CM-ARs) reported in a hospital.

METHODS

A retrospective review of CM-ARs from the electronic spontaneous adverse drug reaction (ADR) report system between January 2011 and August 2012 was conducted. CM-ARs were evaluated in terms of causality, severity, preventability and affected organs. Also, agreement and correlation among the tools used to evaluate CM-ARs were analysed.

RESULTS

The overall reaction rate was 1.5% (n = 286). In total, 269 CM-ARs were identified. For ADR causality, 96.7% (n = 260) and 98.5% (n = 265) were evaluated as "probable" ADR using the Naranjo probability scale and the World Health Organization-Uppsala Monitoring Centre causality categories, whereas 98.1% (n = 264) were evaluated as "certain" with Korean algorithm v. II. Of these, 91.4% (n = 246) were mild in severity and 96.7% (n = 260) were unpreventable. Most patients (n = 233, 86.7%) could be managed with observation and/or simple treatment. The most frequent reaction (n = 383, 79.5%) was dermatological. Spearman's correlation coefficient was 0.667 (p < 0.01), and the agreement was 98.1% between the Naranjo scale and the World Health Organization-Uppsala Monitoring Centre categories. No relationship was seen between CM-AR severity and gender or between in- and outpatients.

CONCLUSION

In our study, most CM-ARs were mild and managed with simple treatment. However, as the number of patients undergoing CT procedures continues to increase, it is essential to identify and observe patients at risk for CM-ARs to prevent severe ADRs.

ADVANCES IN KNOWLEDGE

Continuous careful review of reporting and treatment protocols of CM-ARs is needed to prevent morbidity and mortality.

Mythmaking in medical education and medical practice

BACKGROUND

Despite the emergence of evidence-based medicine, gaps in medical knowledge are filled by tradition, common sense, and experience, giving rise to medical myths.

METHODS

We explored the origins of and evidence related to four medical myths: patients with shellfish allergies should not receive intravenous contrast, patients with atrial fibrillation of less than 48 hours' duration do not require anticoagulation before cardioversion, patients with suspected meningitis should have a computed tomography (CT) scan before a lumbar puncture, and patients with respiratory disease should not receive β-blockers. We conducted a literature review to describe each myth's origins and the quality of supporting evidence.

RESULTS

All patients with allergies, including but not limited to seafood allergies, are at an increased risk for anaphylactoid reactions to radiocontrast. No conclusive studies indicate that patients with atrial fibrillation of less than 48 hours' duration do not require anticoagulation before cardioversion. A CT scan before lumbar puncture in suspected acute bacterial meningitis is a clinically inefficient precaution. β-blockers can be safely used in patients with respiratory disease and may even prevent cardiac events in these patients.

CONCLUSIONS

These familiar myths have maintained prominent roles in medical thinking because they represent wisdom passed down from eminent sources, they teach physiology and medical skills, and they offer physicians a sense of control in the face of uncertainty. In addition to providing scientific evidence, changing physicians' practice requires acknowledging that even meticulous care cannot always avert bad outcomes.

Adherence to PIOPED II investigators' recommendations for computed tomography pulmonary angiography

BACKGROUND

Computed tomography (CT) pulmonary angiography use has increased dramatically, raising concerns for patient safety. Adherence to recommendations and guidelines may protect patients. We measured adherence to the recommendations of Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED II) investigators for evaluation of suspected pulmonary embolism and the rate of potential false-positive pulmonary embolism diagnoses when recommendations of PIOPED II investigators were not followed.

METHODS

We used a structured record review to identify 3500 consecutive CT pulmonary angiograms performed to investigate suspected pulmonary embolism in 2 urban emergency departments, calculating the revised Geneva score (RGS) to classify patients as "pulmonary embolism unlikely" (RGS≤10) or "pulmonary embolism likely" (RGS>10). CT pulmonary angiograms were concordant with PIOPED II investigator recommendations if pulmonary embolism was likely or pulmonary embolism was unlikely and a highly sensitive D-dimer test result was positive. We independently reviewed 482 CT pulmonary angiograms to measure the rate of potential false-positive pulmonary embolism diagnoses.

RESULTS

A total of 1592 of 3500 CT pulmonary angiograms (45.5%) followed the recommendations of PIOPED II investigators. The remaining 1908 CT pulmonary angiograms were performed on patients with an RGS≤10 without a D-dimer test (n=1588) or after a negative D-dimer test result (n=320). The overall rate of pulmonary embolism was 9.7%. Potential false-positive diagnoses of pulmonary embolism occurred in 2 of 3 patients with an RGS≤10 and a negative D-dimer test result.

CONCLUSIONS

Nonadherence to recommendations for CT pulmonary angiography is common and exposes patients to increased risks, including potential false-positive diagnoses of pulmonary embolism.

Contrast alternatives for iodinated contrast allergy and renal dysfunction: options and limitations

Diagnostic angiography and vascular interventions make routine use of iodinated contrast material (ICM). Patients with renal disease or contrast allergy pose limitations on the use of ICM. In such cases, alternative contrast media may be used to carry out the procedure. Current alternatives include carbon dioxide, gadolinium, and dilute ICM. Each of these alternatives has its own unique features and limitations. In the present review article, the current alternatives to ICM are explored, with a focus on the applications and restrictions of each.

Scratching the surface of allergic transfusion reactions

Allergic transfusion reactions (ATRs) are a spectrum of hypersensitivity reactions that are the most common adverse reaction to platelets and plasma, occurring in up to 2% of transfusions. Despite the ubiquity of these reactions, little is known about their mechanism. In a small subset of severe reactions, specific antibody has been implicated as causal, although this mechanism does not explain all ATRs. Evidence suggests that donor, product, and recipient factors are involved, and it is possible that many ATRs are multifactorial. Further understanding of the mechanisms of ATRs is necessary so that rationally designed and cost-effective prevention measures can be developed.

Nonallergic drug hypersensitivity reactions

BACKGROUND

Nonallergic drug hypersensitivities, also referred to as pseudoallergic or anaphylactoid reactions, have clinical manifestations that are often indistinguishable from allergic reactions.

METHODS

We performed a PubMed search using the terms 'drug allergy, drug hypersensitivity, pseudoallergies, anaphylaxis and nonallergic drug reactions' and reviewed 511 publications dated between 1970 and 2012. A total of 160 papers that were relevant to the most common nonallergic drug hypersensitivity reactions were selected for discussion.

RESULTS

Nonallergic drug hypersensitivities do not involve either IgE-mediated (type 1) or delayed (type 4) hypersensitivity. Nonallergic hypersensitivities are commonly referred to as pseudoallergic or idiosyncratic reactions. The common nonallergic drug hypersensitivities are secondary to chemotherapeutic drugs, radiocontrast agents, vancomycin, nonsteroidal anti-inflammatory agents, local anesthetic reactions and opiates. Protocols for skin testing of radiocontrast, nonsteroidal anti-inflammatory agents, local anesthetics and chemotherapeutic agents have been developed, though most have not been validated or standardized. Other diagnostic tests include in vitro-specific IgE tests, and the current 'gold' standard is usually an oral challenge or bronchoprovocation test. In the case of aspirin, even though it is not believed to be IgE-mediated, a 'desensitization' protocol has been developed and utilized successfully, although the mechanism of this desensitization is unclear.

CONCLUSIONS

Diagnostic methods exist to distinguish allergic from nonallergic drug hypersensitivity reactions. The best option in nonallergic drug hypersensitivity is avoidance. If that is not possible, premedication protocols have been developed, although the success of premedication varies amongst drugs and patients.

Outcomes of premedication for non-ionic radio-contrast media hypersensitivity reactions in Korea

BACKGROUND

Radio-contrast media (CM)-related adverse reactions are important clinical problems that may cause fatal anaphylaxis. Accordingly, it has been common practice to premedicate patients who have had previous reactions to CM with corticosteroids, antihistamines, and H2 blockers to prevent hypersensitive reactions. However, the effectiveness of premedication has not been properly demonstrated, especially in cases related to non-ionic CM. In this study, we evaluated the effectiveness of premedication at preventing of non-ionic CM immediate-type hypersensitivity reactions.

METHODS

A total of 30 patients who had been pretreated with corticosteroid and H1 antihistamines and/or H2 blockers in a 3-year period were enrolled. The results of premedication were evaluated in terms of clinical characteristics and the features of breakthrough reactions.

RESULTS

Hypersensitivity reactions were not prevented in 5 of the 30 patients who had experienced prior CM reactions (overall recurrence rate after premedication 16.7%; 4/17 patients with mild previous reactions, and 1/13 patients with severe previous reactions). The recurrence rate after premedication was significantly higher in patients with mild previous reactions than in those with severe reactions (23.5% vs. 7.7%; p<0.001). The breakthrough reactions were similar to the prior reactions in terms of severity and clinical manifestations.

CONCLUSION

Premedication with corticosteroid and H1 antihistamines and/or H2 blockers effectively prevent non-ionic CM-related adverse events in most patients who have had severe previous reactions to CM. However, physicians should be aware of the possibility of premedication failing and of breakthrough reactions, even in cases in which the previous reactions were mild.

The relationship of radiocontrast, iodine, and seafood allergies: a medical myth exposed

BACKGROUND

Radiocontrast agents are some of the most commonly used medications in the emergency department. However, both physicians and patients misunderstand the role that allergies play in reactions to radiocontrast media, especially with regards to shellfish and iodine.

OBJECTIVES

We sought to review the literature describing rates of contrast reactions and risk of contrast administration to patients with iodine allergy, shellfish or seafood allergies, or prior reactions to intravenous iodinated contrast.

METHOD

Both authors independently performed literature reviews, including position statements of stakeholder organizations, to gain perspective on important issues. They subsequently performed a systematic search for articles that estimated the risk of administration of iodinated contrast to those with a prior history of contrast reaction, "iodine allergy," or reaction to seafood or shellfish.

RESULTS

The risk of reactions to contrast ranges from 0.2-17%, depending on the type of contrast used, the severity of reaction considered, and the prior history of any allergy. The risk of reaction in patients with a seafood allergy is similar to that in patients with other food allergies or asthma. A history of prior reaction to contrast increases the risk of mild reactions to as high as 7-17%, but has not been shown to increase the rate of severe reactions. Severe reactions occur in 0.02-0.5% and deaths in 0.0006-0.006%; neither have been related to "iodine allergy," seafood allergy, or prior contrast reaction. Low-osmolality contrast media became available in 1988, and many of the higher risk estimates were from the era before it was widely available.

CONCLUSIONS

Iodine is not an allergen. Atopy, in general, confers an increased risk of reaction to contrast administration, but the risk of contrast administration is low, even in patients with a history of "iodine allergy," seafood allergy, or prior contrast reaction. Allergies to shellfish, in particular, do not increase the risk of reaction to intravenous contrast any more that of other allergies.

[Immediate and delayed hypersensitivity reactions to iodinated radiographic contrast agents: an update]

Diagnostic and interventional radiology of patients is nowadays crucial with increasing requirement for iodinated contrast agents infusion. Besides adverse reactions after administration of the iodinated contrast agents due to their toxicity, immediate hypersensitivity reactions and reactions resembling delayed hypersensitivity appearing from 1 hour to several days later, have been reported. Patients at high risk to develop such adverse events have to be detected on the basis of their risk factors in order to prevent or limit serious outcomes. Previous reactions to contrast media, asthma, atopy and cardiovascular disorders are risk factors for anaphylactic or anaphylactoid reactions. Female gender, age and beta-blockers increase the severity. This article aims to summarize the risk of allergic reactions related to the use of iodinated contrast agents and to suggest a way for diagnosis, treatment and prevention according to each clinical situation.

The basophil activation test in immediate-type drug allergy

Diagnosis of drug allergy involves first the recognition of sometimes unusual symptoms as drug allergy and, second, the identification of the eliciting drug. This is an often difficult task, as the clinical picture and underlying pathomechanisms are heterogeneous. In clinical routine, physicians frequently have to rely upon a suggestive history and eventual provocation tests, both having their specific limitations. For this reason both in vivo (skin tests) and in vitro tests are investigated intensively as tools to identify the disease-eliciting drug. One of the tests evaluated in drug allergy is the basophil activation test (BAT). Basophils with their high-affinity IgE receptors are easily accessible and therefore can be used as indicator cells for IgE-mediated reactions. Upon allergen challenge and cross-linking of membrane-bound IgE antibodies (via Fc-epsilon-RI) basophils up-regulate certain activation markers on their surface such as CD63 and CD203c, as well as intracellular markers (eg, phosphorylated p38MAPK). In BAT, these alterations can be detected rapidly on a single-cell basis by multicolor flow cytometry using specific monoclonal antibodies. Combining this technique with in vitro passive sensitization of donor basophils with patients' serum, one can prove the IgE dependence of a drug reaction. This article summarizes the authors' current experience with the BAT in the diagnostic management of immediate-type drug allergy mediated by drug-specific IgE antibodies.

Intravenous radiocontrast induced anaphylactoid reaction: a rare cause of death

Anaphylactoid reaction after the injection of iodinated contrast media can be life threatening. A 23-year-old woman presented to the emergency room with abdominal pain and fever, for couple of days duration. After completion of a computed tomography (CT) scan of the abdomen and pelvis with intravenous contrast, the patient complained of feeling hot and shortness of breath. She became unresponsive, cyanotic, and developed asystole. The patient was successfully intubated without any laryngeal oedema or bronchial spasm. Despite all resuscitation efforts the patient died. The patient had undergone CT scans with contrast three times in the past. An autopsy could not reveal any obvious cause and the serum tryptase concentration was 211 ng/ml (normal <9 ng/ml).

Anaphylaxis to iodinated contrast material: nonallergic hypersensitivity or IgE-mediated allergy?

OBJECTIVE

Contrast material is generally well tolerated although approximately 1% of patients who receive low-osmolar nonionic contrast material will develop anaphylaxis symptoms. Because most anaphylactic reactions are mild and nonallergic, clinically mimicking immunoglobulin E (IgE)-mediated allergy, diagnostic skin testing has been discussed controversially in the past and prophylactic pretreatment drug regimens are recommended instead. In the past 6 years, all patients with contrast material-induced anaphylaxis have been subjected to allergologic diagnostic procedures to clearly differentiate allergic and nonallergic anaphylaxis. Thus the purpose of our study was to identify and differentiate IgE-mediated allergy and nonallergic contrast material-induced hypersensitivity. Furthermore, the objective of our diagnostic procedures was not only to identify the culprit contrast material but also to find alternative contrast material for future radiologic interventions.

SUBJECTS AND METHODS

We evaluated 96 patients with anaphylaxis symptoms after contrast material application using standardized intradermal skin testing. In patients with positive skin tests, the IgE-mediated allergy was further evaluated with in vitro and challenge tests.

RESULTS

In four patients (suffering from anaphylaxis grades 2 and 3) out of the 96 (4.2%), skin tests and basophil activation tests strongly suggested IgE-mediated allergy to the contrast materials iopromide (two patients), iomeprol, and iopentol. In two patients with allergies to iopromide and iomeprol, alternative nonionic monomer contrast materials were tolerated, as identified in controlled challenge tests with iopamidol and iopromide, respectively.

CONCLUSION

The evaluation of patients with contrast material-induced anaphylaxis (at least those with anaphylaxis > or = grade 2) should always include appropriate skin tests ensuring that patients with an IgE-mediated allergy are not missed. Moreover, allergologic testing may identify a contrast material of the group of nonionic monomers that will be tolerated in future radiologic interventions.

Seafood allergy and radiocontrast media: are physicians propagating a myth?

BACKGROUND

Recent surveys have indicated that the misconception that seafood allergy confers a disproportionately increased risk of adverse reactions to radiocontrast media remains pervasive among physicians and patients. One possible explanation for the persistence of this notion is that physicians responsible for radiocontrast administration are inadvertently contributing to its propagation.

METHODS

An anonymous survey was sent to 231 faculty radiologist and interventional cardiologists at 6 Midwest academic medical centers. Two questions dealt directly with seafood allergy related to radiocontrast media administration, and 6 questions served as distracters.

RESULTS

Sixty-nine percent of responders indicated that they inquire about a history of seafood allergy before radiocontrast media administration. Some 37.2% of responders replied that they would withhold radiocontrast media or recommend premedication on the basis of a history of seafood allergy.

CONCLUSION

Even among faculty physicians at university medical centers, the notion of seafood allergy as a significant risk factor for adverse radiocontrast media reactions remains pervasive. Even if no action is taken on the basis of the answer, it seems probable that the act of inquiring about seafood allergy before radiocontrast media administration could lead patients and trainees to presume an inherent risk in patients who are seafood allergic, thus propagating the notion. Physician education with respect to seafood allergy and radiocontrast media administration is vital to halting the persistence of this misconception.

Magnetic resonance angiography

MRA and MRI have become increasingly important diagnostic modalities in vascular surgery. The ability to obtain cross-sectional and angiographic images by these noninvasive and non-nephrotoxic modalities represents one of the most significant advances in vascular surgery over the past decade. We review the current status of MRI and MRA in vascular surgical practice.

Osmometric and water-transporting properties of guinea pig cardiac myocytes

To elucidate the mechanism of water flux across heart cell membranes, osmotically induced volume changes and sarcolemmal water permeability were evaluated in isolated guinea pig ventricular myocytes by videomicroscopic measurements of cell surface dimensions. Superfusion with anisosmotic solution (0.5-4 times normal osmolality) caused a rapid (lt;3 min to new steady state) and reversible cell swelling or shrinkage mainly because of proportional changes in cell width and thickness. The van't Hoff relationship between relative cell volume and the reciprocal of relative osmolality was linear and predicted an apparent osmotically dead space of approximately 35% cell volume. The osmotic water permeability coefficient (P(f)) measured from the time course of cell swelling/shrinkage was approximately 22 microm.s(-1) at 35 degrees C. Arrhenius activation energy (E(a)), a measure of the energy barrier to water flux, was approximately 3.8 kcal.mol(-1) between 11 and 35 degrees C; this value is equivalent to E(a) for free-water diffusion in bulk solution ( approximately 4 kcal.mol(-1)). Treatment with 0.1 mM Hg(2+), a sulfhydryl-oxidizing reagent, reduced P(f) by approximately 90%, and the sulfhydryl-reducing reagent dithiothreitol (10 mM) antagonized the inhibitory action of Hg(2+). E(a) measured from Hg(2+)-treated myocytes (12.3 kcal.mol(-1)) was in the range of that for diffusional water movement through the lipid bilayers (>10 kcal.mol(-1)). Although the observed P(f) is small in magnitude, both the low E(a) and the sulfhydryl-related modifications of P(f) are characteristic of channel-mediated water transport. These data suggest that water channels form a major conduit for water crossing the sarcolemma of guinea-pig heart cells.

Cardiopulmonary arrest induced by anaphylactoid reaction with contrast media

Anaphylactoid reactions to iodinated contrast media can cause life-threatening events and even death. A 44-year-old woman presented with cardiopulmonary arrest (CPA) immediately following the administration of nonionic iodinated contrast media for an intravenous pyelography. Her cardiac rhythm during CPA was asystole. She was successfully resuscitated by the radiologists supported by paged emergency physicians using the prompt intravenous administration of 1 mg of epinephrine. Neither laryngeal edema nor bronchial spasm was observed during the course of treatment, and she was discharged on the 4th day without any complications. The patient did not have a history of allergy, but had experienced a myocardial infarction and aortitis. She had undergone 11 angiographies and had been taking a beta-adrenergic receptor antagonist. Planned emergency medical backup is advisable to ensure resuscitation in the event of an anaphylactoid reaction to the use of contrast media in-hospital settings.

Cardiac arrest after administration of Omnipaque radiocontrast medium during endoluminal repair of abdominal aortic aneurysm

We describe a case of acute cardiovascular collapse in a patient with end-stage renal failure undergoing endoluminal repair of an abdominal aortic aneurysm. The 61-yr-old man suffered cardiac arrest shortly after administration of radiocontrast medium (Omnipaque), during deployment of the endovascular device. He had received the same contrast solution for diagnostic angiography on the previous day. He was successfully resuscitated and recovered completely. The differential diagnosis and management are discussed.