Delayed-type heparin allergy: diagnostic procedures and treatment alternatives-a case series including 15 patients

Single-step controlled synthesis of flower-like gold nanoparticles stabilized by chitosan for sensitive detection of heparin using a surface-enhanced Raman scattering method

A novel single-step and template-free procedure, including controlled synthesis of gold flowers (AuNFs), conjugation to a 4-MBA reporter, and stabilization with chitosan, is proposed to develop the SERS tags-based nanoparticles for trace detection of heparin. This SERS detection assay is based on the aggregation/non-aggregation balance of AuNFs-4-MBA@chitosan nanoparticles, which was induced by adding a very low concentration of heparin in the as-synthesized colloidal solutions. SERS-tag colloids are prepared by mixing chitosan with HAuCl₄ and 4-mercapto benzoic acid before being reduced with ascorbic acid under appropriate pH conditions. The formed AuNFs-4-MBA@chitosan nanoparticles were positively charged with high stability and well-dispersed in aqueous media. Based on understanding each reaction component's role in the preparation of the SERS tag colloid, we aim to simplify the controlled synthesis and Raman probe conjugation process. The average size of AuNFs is below 90 nm, fine-tuned in shape and effectively conjugated to the Raman reporter molecules 4-MBA. These as-prepared SERS tag-based AuNFs have good biocompatibility and are virtually non-toxic, as studied with fibroblast and MCF-7 cells. Through these SERS-tag colloids, the trace detection of heparin is improved, with a wide detection window (0.01 to 100 ppm), high reproducibility (RSD value of 3.56%), limit of detection (LOD) of 0.054 ppm, and limit of quantification (LOQ) of 0.17 ppm. Comparison experiments show that the SERS-tag colloids possess good selectivity over other ions, and organic and amino acid substances. The results provide the capability and the potential for application under complex biological conditions and future biosensing based on SERS signal amplification.

Cutaneous hypersensitivity reaction to low molecular weight heparins in pregnancy, cross reactivity and prednisolone treatment: A case report

In pregnant women, low molecular weight heparin is recommended as the preferred agent for venous thromboembolism prophylaxis and treatment. Despite their widespread application, heparin-induced skin lesions are probably under-reported and under-estimated. We present a case report of a primigravida treated with low molecular weight heparin for deep vein thrombosis, who developed a delayed-type hypersensitivity reaction to enoxaparin, tinzaparin and dalteparin. As the patient was pregnant, treatment options were restricted. Tolerance was achieved with dalteparin with adjuvant administration of prednisolone. An attempt to decrease prednisolone dose triggered delayed-type hypersensitivity reaction recurrence that was solved by keeping the initial prednisolone prescription. To the best of our knowledge, there are no described cases using this approach. In cases of delayed-type hypersensitivity reaction to low molecular weight heparin during pregnancy our case suggests that switching low molecular weight heparin and adjuvant administration of prednisolone can be an option.

COVID-19 Disease, Women's Predominant Non-Heparin Vaccine-Induced Thrombotic Thrombocytopenia and Kounis Syndrome: A Passepartout Cytokine Storm Interplay

Coronavirus disease 2019 (COVID-19) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) constitute one of the deadliest pandemics in modern history demonstrating cardiovascular, gastrointestinal, hematologic, mucocutaneous, respiratory, neurological, renal and testicular manifestations and further complications. COVID-19-induced excessive immune response accompanied with uncontrolled release of cytokines culminating in cytokine storm seem to be the common pathogenetic mechanism of these complications. The aim of this narrative review is to elucidate the relation between anaphylaxis associated with profound hypotension or hypoxemia with pro-inflammatory cytokine release. COVID-19 relation with Kounis syndrome and post-COVID-19 vaccination correlation with heparin-induced thrombocytopenia with thrombosis (HITT), especially serious cerebral venous sinus thrombosis, were also reviewed. Methods: A current literature search in PubMed, Embase and Google databases was performed to reveal the pathophysiology, prevalence, clinical manifestation, correlation and treatment of COVID-19, anaphylaxis with profuse hypotension, Kounis acute coronary syndrome and thrombotic events post vaccination. Results: The same key immunological pathophysiology mechanisms and cells seem to underlie COVID-19 cardiovascular complications and the anaphylaxis-associated Kounis syndrome. The myocardial injury in patients with COVID-19 has been attributed to coronary spasm, plaque rupture and microthrombi formation, hypoxic injury or cytokine storm disposing the same pathophysiology with the three clinical variants of Kounis syndrome. COVID-19-interrelated vaccine excipients as polysorbate, polyethelene glycol (PEG) and trometamol constitute potential allergenic substances. Conclusion: Better acknowledgement of the pathophysiological mechanisms, clinical similarities, multiorgan complications of COVID-19 or other viral infections as dengue and human immunodeficiency viruses along with the action of inflammatory cells inducing the Kounis syndrome could identify better immunological approaches for prevention, treatment of the COVID-19 pandemic as well as post-COVID-19 vaccine adverse reactions.

Postpartum prophylaxis of venous thromboembolism with anticoagulation: A case report

Although there is a remarkably high risk of venous thromboembolism (VTE) during pregnancy and postpartum, a cautious approach is needed while initiating therapeutic and prophylactic anticoagulant therapy. The merits of heparin for thromboprophylaxis in postpartum patients are exaggerated, and its risk is generally overlooked. This study aimed to report the inappropriate use of anticoagulants in postpartum patients. The patient in this report was a 31-year-old healthy woman who had had a normal spontaneous vaginal delivery and visited the hospital a 3-day history of small itchy blisters at the enoxaparin injection sites. An examination revealed class II obesity. The Naranjo Scale assessment showed the possibility of an enoxaparin-induced hypersensitivity reaction. The clinical care team decided to discontinue the heparin. A follow-up examination did not show any signs of VTE. Although many pregnant and postnatal women might need VTE prophylaxis, routine anticoagulation for such a population is not essential. Clinicians should weigh the risks versus benefits to avoid any adverse drug reactions that may occur with this class of medication.

Non-immediate heparin and heparinoid cutaneous allergic reactions: a role for fondaparinux

Non-immediate allergic cutaneous reactions to heparins have been increasingly reported, typically manifesting as large, eczematous plaques at sites of subcutaneous injection. Patients may demonstrate cross-reactivity between unfractionated heparin, low molecular weight heparin and semi-synthetic heparinoids, making finding an alternative difficult. Fondaparinux has been identified as a useful alternative in such patients; here we present the first two documented cases in Australia and a literature review.

Necessity of heparin for maintaining peripheral venous catheters: A systematic review and meta-analysis

Heparin has typically been used as a flushing or infusion solution for vascular lines in daily practice. However, several clinical trials have yielded controversial results about the benefits of heparin in maintaining peripheral venous catheters. The present meta-analysis was conducted to evaluate the efficacy of heparin on the patency profiles and complications in peripheral intravenous catheters. PubMed, Embase and Cochrane Central Register of Controlled Trials were searched up to February 2016 for randomized controlled trials comparing heparin with placebo in maintaining peripheral intravenous catheters. Additional studies were retrieved from the reference lists of identified articles. In total 32 eligible studies were included, from which the pooled standard mean difference (SMD), relative risk (RR) and corresponding 95% confidence interval (CI) were calculated. The use of heparin as a continuous infusion significantly prolonged the duration of patency (SMD, 0.90; 95% CI, 0.48-1.32; P<0.001), reduced rates of infusion failure (RR, 0.83; 95% CI, 0.76-0.92; P<0.001) and occlusion (RR, 0.82; 95% CI, 0.69-0.98; P<0.05) in a peripheral intravenous catheter. However, there were no significant changes in the duration of patency and infusion failure when heparin was used intermittently as a flushing solution, although a significantly decreased risk of occlusion was observed in this setting (RR, 0.80; 95% CI, 0.66-0.98; P<0.05). Furthermore, the risk of phlebitis was significantly decreased by both continuous infusion (RR, 0.66; 95% CI, 0.58-0.75; P<0.01) and intermittent flushing (RR, 0.70; 95% CI, 0.56-0.86; P<0.01) of heparin in peripheral venous catheters. In conclusion, the use of heparin as continuous infusion in peripheral intravenous catheters improved the duration of patency, reduced infusion failure and phlebitis, whereas heparin as intermittent flushing showed more benefits in ameliorating phlebitis rather than in patency profiles.

Adverse Drug Reactions and Cutaneous Manifestations Associated With Anticoagulation

Anticoagulants are amongst the most commonly prescribed medications worldwide. Although rare, localised and systemic drug reactions have been reported with anticoagulants that can lead to significant morbidity and mortality. Some of the first signs of drug reactions to anticoagulants are cutaneous changes that, when recognised early, can prevent significant complications. Dermatologists should be aware of these changes to make an early and accurate diagnosis. This is particularly important in instances of skin-induced necrosis caused by systemic toxicity to anticoagulants. This review discusses adverse drug reactions to the traditional anticoagulants, warfarin and heparin, and the newer direct oral anticoagulants (DOACs) such as the thrombin inhibitor, dabigatran, and the factor Xa inhibitors, rivaroxaban, apixaban, and edoxaban. In particular, this review provides dermatologists with a framework for early diagnosis and management of patients with drug reactions to anticoagulants and alerts them to potential bleeding complications associated with minor procedures.

Hypersensitivity reactions in patients receiving hemodialysis

OBJECTIVE

To describe hypersensitivity reactions in patients receiving maintenance hemodialysis.

DATA SOURCES

PubMed search of articles published during the past 30 years with an emphasis on publications in the past decade.

STUDY SELECTIONS

Case reports and review articles describing hypersensitivity reactions in the context of hemodialysis.

RESULTS

Pharmacologic agents are the most common identifiable cause of hypersensitivity reactions in patients receiving hemodialysis. These include iron, erythropoietin, and heparin, which can cause anaphylactic or pseudoallergic reactions, and topical antibiotics and anesthetics, which lead to delayed-type hypersensitivity reactions. Many hypersensitivity reactions are triggered by complement activation and increased bradykinin resulting from contact system activation, especially in the context of angiotensin-converting enzyme inhibitor use. Several alternative pharmacologic preparations and dialyzer membranes are available, such that once an etiology for the reaction is established, recurrences can be prevented without affecting the quality of care provided to patients.

CONCLUSION

Although hypersensitivity reactions are uncommon in patients receiving hemodialysis, they can be life-threatening. Moreover, considering the large prevalence of the end-stage renal disease population, the implications of such reactions are enormous. Most reactions are pseudoallergic and not mediated by immunoglobulin E. The multiplicity of potential exposures and the complexity of the environment to which patients on dialysis are exposed make it challenging to identify the precise cause of these reactions. Great diligence is needed to investigate hypersensitivity reactions to avoid recurrence in this high-risk population.

Bivalirudin as an Alternative Anticoagulant for Cardiopulmonary Bypass During Adult Cardiac Surgery-A Change in Practice

The referral of patients for open heart surgery, presenting with a history of heparin hypersensitivity instigated a multidisciplinary effort to find an alternative anticoagulant to heparin. The various options mentioned in the literature call for changes in the routine practice of open heart surgery on cardiopulmonary bypass. These changes involve mostly the perfusion setup and conduct on bypass and to a lesser extent the anesthetic and surgical practice. Nevertheless, the different professions involved in the cardiac surgical firm discussed the proposed changes in a multidisciplinary effort. A new protocol was drafted, endorsed, and executed. The authors highlight these changes and their successful use in the subsequent case study.