Hypersensitivity Reactions to Iodinated Contrast Media

Risks and Benefits of Cervical Transforaminal Epidural Steroid Injections: A Comprehensive Review

PURPOSE OF REVIEW

Cervical transforaminal epidural steroid injections (CTFESIs) are widely used for the treatment of radicular pain caused by cervical spine pathology, including disc herniations and foraminal stenosis. This review aims to analyze the risks and benefits of CTFESIs, address their efficacy and safety profile, improve clinical decision-making, and educate interventional pain medicine physicians.

RECENT FINDINGS

CTFESIs have demonstrated benefits such as pain relief, functional improvement, and the potential to avoid surgical interventions. However, their use is limited by safety concerns due to the proximity of vascular structures in the cervical spine. Complications, including neurological injuries, infections, and vascular injuries, though rare, can be severe. Recent studies emphasize the importance of using advanced procedural techniques, such as fluoroscopic guidance and non-particulate corticosteroids, to minimize risks. CTFESIs remain a valuable tool for managing cervical radiculopathy in selected patients. While they provide substantial therapeutic and diagnostic benefits, careful patient selection and adherence to safety protocols are crucial to minimizing serious complications. This review compiles current evidence to assist clinicians in evaluating the risks and benefits of CTFESIs in clinical practice.

CAR/CSACI Practice Guidance for Contrast Media Hypersensitivity

Contrast media, including iodinated contrast media and gadolinium-based contrast agents, are commonly administered pharmaceuticals with excellent safety profiles. However, a minority of the population may experience a hypersensitivity reaction following intravenous administration. Hypersensitivity reactions can be immediate or delayed, and range from mild, such as urticaria, to severe, including anaphylaxis. There is emerging evidence that longstanding pretreatment protocols, such as diphenhydramine and corticosteroids, are ineffective and have the potential for side effects and other harms. Moreover, the evidence for efficacy on which this practice is based is weak and outdated. A joint collaborative working group of representatives from the Canadian Association of Radiologists and the Canadian Society of Allergy and Clinical Immunology was assembled to inform medical professionals and hospital policies regarding hypersensitivity reactions to contrast media. The objectives of the working group were to provide an overview of the epidemiology, physiology, risk factors, and types of hypersensitivity reactions; to synthesize the evidence for pretreatment strategies that minimize the risk of a breakthrough reaction for both iodinated contrast media and gadolinium-based contrast agents; to review the allergy investigations used to evaluate patients with a history of severe hypersensitivity reaction; and to provide an overview of existing guidelines. Following appraisal of the evidence, the working group established recommendations based on consensus in this practice guidance.

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.

A large forearm subcutaneous hematoma after contrast extravasation requires surgical managements: A case report

RATIONALE

Large extremity hematoma can rarely happen after contrast extravasation during a contrast-enhanced computed tomography scan. Some hematomas need prompt surgical managements.

PATIENT CONCERNS

A 77-year-old man had acute ischemic stroke and received the thrombolytic and antiplatelet therapies. He had a contrast extravasation during the computed tomography scan and developed a large hematoma in the right forearm, despite without evidence of compartment syndrome.

DIAGNOSIS

Right forearm hematoma, status post contrast extravasation.

INTERVENTIONS

The patient responded poorly to the routine care with arm elevation, cold pack, and wet dressing, and was finally treated by the surgical debridement, vacuum sealing drainage, fascioplasty, and skin flap repair.

OUTCOMES

Right forearm wound healed with a scar.

LESSONS

Large extremity hematoma can happen after contrast extravasation during computed tomography scan, which may require surgical treatments. Careful preparation, close monitor, and prompt managements should be applied in high-risk patients.

Safety of non-ionic contrast media in CT examinations for out-patients: retrospective multicenter analysis of 473,482 patients

OBJECTIVES

This study aimed to explore the incidence of and potential risk factors for adverse drug reactions (ADRs) after non-ionic iodinated contrast media (NICM) administration for CT exams in out-patient settings in China.

MATERIALS AND METHODS

A total of 473,482 out-patients who underwent intravenous NICM between January 1st, 2017, and Dec 31st, 2021, were retrospectively enrolled from three institutions. The occurrence of ADRs and clinical information were recorded. Chi-square test, Poisson regression, and logistic regression analyses were used to evaluate potential ADR risk factors and correlation with demographics, season, and NICM type.

RESULTS

Among the 473,482 patients (mean age 55.22 ± 14.85; 253,499 male) who received intravenous NICM, the overall ADR incidence was 0.110% (522 of 473,482), with 0.099% acute-related drug reactions (469 of 473,482) and 0.0004% serious ADRs (two of 473,482). Iopromide was associated with a higher risk of acute ADRs. Late ADRs were more frequently observed with iodixanol 320. Multi-level logistic regression of patients with acute ADRs and a control group (matched 1:1 for age, gender, NICM, prescriber department, and institution) showed that summer (adjusted OR = 1.579; p = 0.035) and autumn (adjusted OR = 1.925; p < 0.001) were risk factors of acute ADRs. However, underlying disease and scanned body area were not related to a higher ADR incidence.

CONCLUSION

The use of NICM for out-patients is in general safe with a low ADR incidence. The type of contrast medium (iopromide) and the seasons (summer and autumn) were associated with a higher risk of acute ADRs. Late ADRs were more often observed with iodixanol.

CLINICAL RELEVANCE STATEMENT

In comparison to in-patients, out-patients may be exposed to higher risk due to a lack of extensive risk screening, less nursing care, and higher throughput pressure. Safety data about NICM from a large population may complement guidelines and avoid ambiguity.

KEY POINTS

• The incidence and risk factors for adverse events after using non-ionic iodinated contrast media are complex in out-patients. • Non-ionic iodinated contrast media are safe for out-patients and the overall incidence of adverse drug reactions was 0.110%. • There is a higher risk of acute adverse drug reactions in summer and autumn.

Drug provocation tests (DPTs) of contrast media: Useful or not useful? - A narrative review

Drug provocation tests (DPTs) are also used in some patients with a history of a contrast medium (CM)-hypersensitivity reaction. Since the use of contrast agents requires special knowledge that is present in radiology but not necessarily in allergology, this overview should close the knowledge gaps. The literature, and the package inserts of the industry dealing with DPTs in contrast hypersensitivity reactions was analyzed and the results presented. Historical analyses revealed that provocation tests were already done in the past, and called pre-testing. Due to disadvantages, this diagnostic tool was abandoned. A few years later, DPT was introduced as an innovative diagnostic procedure. The DPT has the 3 main disadvantages: a missing standardization, patients at risk (such as compromised renal function) are rarely taken into account, and a negative DPT does not exclude a subsequent CM reaction. DPTs (formerly called pre-testing) are a well-known method for diagnosing CM-related hypersensitivity reactions. Since the disadvantages of this diagnosis outweigh the advantages, we propose replacing DPT with routine contrast-enhanced imaging examination in radiology.

Artificial Intelligence Chatbots' Understanding of the Risks and Benefits of Computed Tomography and Magnetic Resonance Imaging Scenarios

PURPOSE

Patients may seek online information to better understand medical imaging procedures. The purpose of this study was to assess the accuracy of information provided by 2 popular artificial intelligence (AI) chatbots pertaining to common imaging scenarios' risks, benefits, and alternatives.

METHODS

Fourteen imaging-related scenarios pertaining to computed tomography (CT) or magnetic resonance imaging (MRI) were used. Factors including the use of intravenous contrast, the presence of renal disease, and whether the patient was pregnant were included in the analysis. For each scenario, 3 prompts for outlining the (1) risks, (2) benefits, and (3) alternative imaging choices or potential implications of not using contrast were inputted into ChatGPT and Bard. A grading rubric and a 5-point Likert scale was used by 2 independent reviewers to grade responses. Prompt variability and chatbot context dependency were also assessed.

RESULTS

ChatGPT's performance was superior to Bard's in accurately responding to prompts per Likert grading (4.36 ± 0.63 vs 3.25 ± 1.03 seconds, P < .0001). There was substantial agreement between independent reviewer grading for ChatGPT (κ = 0.621) and Bard (κ = 0.684). Response text length was not statistically different between ChatGPT and Bard (2087 ± 256 characters vs 2162 ± 369 characters, P = .24). Response time was longer for ChatGPT (34 ± 2 vs 8 ± 1 seconds, P < .0001).

CONCLUSIONS

ChatGPT performed superior to Bard at outlining risks, benefits, and alternatives to common imaging scenarios. Generally, context dependency and prompt variability did not change chatbot response content. Due to the lack of detailed scientific reasoning and inability to provide patient-specific information, both AI chatbots have limitations as a patient information resource.

Drug-Induced Anaphylaxis: National Database Analysis

(1) Background: National health system databases represent an important source of information about the epidemiology of adverse drug reactions including drug-induced allergy and anaphylaxis. Analysis of such databases may enhance the knowledge of healthcare professionals regarding the problem of drug-induced anaphylaxis. (2) Methods: A retrospective descriptive analysis was carried out of spontaneous reports (SRs) with data on drug-induced anaphylaxis (SRsAs) extracted from the Russian National Pharmacovigilance database (analyzed period 2 April 2019-21 June 2023). The percentage of SRsAs among SRs of drug-induced allergy (SRsDIAs) was calculated, as well as of pediatric, elderly, and fatal SrsAs. Drugs involved in anaphylaxis were assessed among total SRsAs, pediatric, and elderly SRsAs, and among fatal SRsAs. Demographic parameters of patients were assessed. (3) Results: SRsAs were reported in 8.3% of SRsDIAs (2304/27,727), the mean age of patients was 48.2 ± 15.8 years, and females accounted for 53.2% of cases. The main causative groups of drugs were antibacterials (ABs) for systemic use (44.6%), local anesthetics (20.0%), and cyclooxygenase (COX) inhibitors (10.1%). Fatal SRsAs were reported in 9.5% (218/2304) of cases, the mean age of patients was 48.0 ± 16.7 years, and females accounted for 56.4% of cases. Pediatric SRsAs accounted for 3.9% of pediatric SRsDIAs and 5.8% of all SRsAs, with a mean age of 11.8 ± 4.5 years, and females acccounted for 51.9% of cases. Elderly SRsAs accounted for 2% of elderly SRsDIAs and 2.8% of all SRsAs, and the mean age was 73.0 ± 5.3 years, and females accounted for 43.5% of cases. ABs caused 40% of SRsAs in the elderly, 42.9% in children, and 50% of fatal SRsAs. (4) Conclusions: Our study revealed a relatively high proportion of anaphylaxis among SRs of drug-induced allergy. ABs were the most prevalent causative agents, especially in fatal SRsAs.

Preventing post-contrast acute kidney injury and hypersensitivity reactions: UK national audit

AIM

To audit UK radiology departmental protocols related to the prevention of Iodine-based contrast media (ICM) adverse drug reactions (ADRs) and to assess their compliance with the Royal College of Radiologists (RCR) endorsed Royal Australian and New Zealand College of Radiologists' 2018 Iodinated Contrast Guidelines.

MATERIALS AND METHODS

Questionnaires were sent to all UK acute National Health Service (NHS) providers treating adult patients with an audit lead registered with the RCR (162 providers encompassing 211 hospital radiology departments). The questionnaire included three main sections: renal function screening, renal protection regimens, and hypersensitivity reactions prevention and follow-up. Data collection was conducted between April and July 2022.

RESULTS

Sixty-one per cent (129/211) of departments responded, representing 67% of eligible providers. An independent imaging services provider supplied one additional set of data (n=130 overall). Of the responding departments, for post-contrast acute kidney injury (PC-AKI), 41% and 56% had the recommended risk assessment for inpatients and outpatients, respectively. Renal function testing was often over-utilised, and their results were applied improperly. Sixty-eight per cent of departments used the advised threshold for considering renal protection. For hypersensitivity reactions, 9% of departments had the correct risk assessment. Thirty-six per cent of departments had the correct risk mitigation protocol for identified high-risk patients. The documentation and follow-up for hypersensitivity reactions were similarly inadequate.

CONCLUSION

Local protocols on preventing ICM ADRs were largely non-compliant with RCR guidelines. Departments need to update their protocols in line with current evidence to avoid iatrogenic morbidity or unnecessary tests and over-precaution.

Stroke in a patient of anaphylaxis-a case report and brief review

BACKGROUND

The use of nonionic low-osmolar contrast media has significantly reduced the risk of hypersensitivity reactions. Despite this, severe reactions continue to occur unpredictably. An ischemic stroke in the setting of anaphylaxis is extremely rare.

CASE REPORT

A 64-year-old male with no prior allergies went into anaphylactic shock following the administration of iohexol which improved after treatment. He later developed a multi-territorial ischemic stroke.

CONCLUSION

An ischemic stroke in the setting of an anaphylaxis is a rare occurrence, which can be attributed to multiple factors in our patient.

Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension: a clinical consensus statement of the ESC working group on pulmonary circulation and right ventricular function

The current treatment algorithm for chronic thromboembolic pulmonary hypertension (CTEPH) as depicted in the 2022 European Society of Cardiology (ESC)/European Respiratory Society (ERS) guidelines on the diagnosis and treatment of pulmonary hypertension (PH) includes a multimodal approach of combinations of pulmonary endarterectomy (PEA), balloon pulmonary angioplasty (BPA) and medical therapies to target major vessel pulmonary vascular lesions, and microvasculopathy. Today, BPA of >1700 patients has been reported in the literature from centers in Asia, the US, and also Europe; many more patients have been treated outside literature reports. As BPA becomes part of routine care of patients with CTEPH, benchmarks for safe and effective care delivery become increasingly important. In light of this development, the ESC Working Group on Pulmonary Circulation and Right Ventricular Function has decided to publish a document that helps standardize BPA to meet the need of uniformity in patient selection, procedural planning, technical approach, materials and devices, treatment goals, complications including their management, and patient follow-up, thus complementing the guidelines. Delphi methodology was utilized for statements that were not evidence based. First, an anatomical nomenclature and a description of vascular lesions are provided. Second, treatment goals and definitions of complete BPA are outlined. Third, definitions of complications are presented which may be the basis for a standardized reporting in studies involving BPA. The document is intended to serve as a companion to the official ESC/ERS guidelines.

Alveolar Hemorrhage Following Positron Emission Tomography/Computed Tomography in 2 Separate Episodes 5 Months Apart

BACKGROUND Positron emission tomography/computed tomography (PET/CT) has become one of the most prominent modalities worldwide for the diagnosis and surveillance of malignancies. Current clinical imaging guidelines report adverse reactions following PET/CT, especially due to contrast-induced toxicities, such as contrast-induced nephropathy and other rare reactions attributed to a hypersensitivity immune response, such as bronchospasm. Other rare lung toxicities were reported in a few case reports. Herein, we report repeated episodes of alveolar hemorrhage, a novel adverse response to PET/CT, occurring on 2 separate occasions 5 months apart. CASE REPORT A 57 year-old female patient with breast carcinoma managed by mastectomy, adjuvant chemotherapy, irradiation, and hormonal therapy presented with massive alveolar hemorrhage following PET/CT performed for surveillance 13 years after completion of chemotherapy and irradiation. An additional episode of massive alveolar hemorrhage occurred 5 months later following PET/CT, with respiratory failure requiring mechanical ventilation. Fluorine-18 fluorodeoxyglucose ([¹⁸F] FDG) and iohexol were used for imaging on both occasions. Common causes of alveolar hemorrhage, including malignancy, were excluded. CONCLUSIONS The repeated episodes immediately following PET/CT and the earlier and more intense respiratory failure following the second event raise the possibility of an immune-mediated alveolar hemorrhage in response to either the administration of iodinated radiocontrast agent or to [¹⁸F] FDG.