Pathophysiology and Diagnosis of Drug-Induced Immune Thrombocytopenia

Hematological adverse events associated with anti-MRSA agents: a real-world analysis based on FAERS

This study investigated the patterns of hematological adverse events related to daptomycin (DAP), tigecycline (TIG), vancomycin (VAN) and linezolid (LIN) in the FDA Adverse Event Reporting System (FAERS). Adverse event associations were analyzed through calculating reporting odds ratio (ROR), proportional reporting ratio (PRR), multiple gamma Poisson shrinkage (MGPS), and Bayesian confidence propagation neural network (BCPNN). A comprehensive descriptive analysis was also conducted considering factors such as age, gender, daily dose, cumulative dose, and time to onset. The leading hematologic adverse events were eosinophilia for daptomycin, coagulation abnormalities and thrombocytopenia for tigecycline, thrombocytopenia, neutropenia, and anemia for linezolid, and thrombocytopenia, eosinophilia, and neutropenia for vancomycin. Most of the affected patients were over 55 years old. Daily doses for the tigecycline and daptomycin groups exceeded the standard daily dose. The times to onset were 14.00 days for daptomycin (interquartile range [IQR], 4.00-21.00), 6.00 days for tigecycline (IQR, 2.00-9.00), 10.00 days for linezolid (IQR, 4.00-16.5), and 10.00 days for vancomycin (IQR,5.00-20.00). It is essential to intensify early monitoring and identification of these adverse events, especially in the context of off-label dosages and for elderly patients and individuals taking medication for over one week.

Fever and reversible laboratory abnormalities associated with prolonged use of piperacillin/tazobactam: A case report

Piperacillin/tazobactam is a widely used anti-infective agent. However, prolonged use can lead to adverse drug reactions, primarily presenting as fever and various abnormal laboratory test results. Certain abnormal test outcomes may mislead clinical assessments. We present a case of a 50-year-old Chinese woman who developed a fever and abnormal blood tests after receiving piperacillin/tazobactam for more than 2 weeks. These tests showed elevated levels of C-reactive protein, procalcitonin, transaminases, myocardial enzymes, and a significant increase in D-dimer. After stopping piperacillin/tazobactam, all relevant test results returned to normal within 10 days. It is imperative for clinicians to be vigilant of this adverse effect in patients undergoing extended piperacillin/tazobactam treatment, as early recognition can prevent unnecessary diagnostic tests and therapeutic interventions.

Ceftriaxone-induced thrombocytopenia during tuberculosis treatment: a case report

We present a case of drug-induced immune thrombocytopenia (DITP) proven to be due to ceftriaxone instead of assumed tuberculostatic treatment in a patient with miliary tuberculosis. It is important to identify the culprit drug in DITP to avoid discontinuing essential treatment, especially when more than one drug is implicated. In these cases additional analysis (drug-dependent platelet antibody testing) should be considered to prevent unnecessary replacement of a first-line regimen of tuberculostatic treatment with an alternative treatment regime.

ACVIM consensus statement on the diagnosis of immune thrombocytopenia in dogs and cats

Immune thrombocytopenia (ITP) is the most common acquired primary hemostatic disorder in dogs. Immune thrombocytopenia less commonly affects cats but is an important cause of mortality and treatment-associated morbidity in both species. Immune thrombocytopenia remains a diagnosis of exclusion for which diagnostic guidelines are lacking. Primary, or non-associative, ITP refers to autoimmune platelet destruction. Secondary, or associative, ITP arises in response to an underlying disease trigger. However, evidence for which comorbidities serve as ITP triggers has not been systematically evaluated. To identify key diagnostic steps for ITP and important comorbidities associated with secondary ITP, we developed 12 Population Evaluation/Exposure Comparison Outcome (PECO) format questions. These questions were addressed by evidence evaluators utilizing a literature pool of 287 articles identified by the panelists using a structured search strategy. Evidence evaluators, using panel-designed templates and data extraction tools, summarized evidence and created guideline recommendations that then were integrated by diagnosis and comorbidity domain chairs. The revised PECO responses underwent a Delphi survey process to reach consensus on final guidelines. A combination of panel expertise and PECO responses were employed to develop algorithms for diagnosis of ITP in dogs and cats, which also underwent 4 iterations of Delphi review. Comorbidity evidence evaluators employed an integrated measure of evidence (IME) tool to determine evidence quality for each comorbidity; IME values combined with evidence summaries for each comorbidity were integrated to develop ITP screening recommendations, which also were subjected to Delphi review. Commentary was solicited from multiple relevant professional organizations before finalizing the consensus. The final consensus statement provides clinical guidelines for the diagnosis of, and underlying disease screening for, ITP in dogs and cats. The systematic consensus process identified numerous knowledge gaps that should guide future studies. This statement is a companion manuscript to the ACVIM Consensus Statement on the Treatment of Immune Thrombocytopenia.

Disease-modifying therapies and hematological disorders: a systematic review of case reports and case series

Introduction

Disease modifying therapies (DMTs) used to treat multiple sclerosis (MS) can be associated to the occurrence of hematological disorders. This systematic review aims to provide an overview of these events occurring in real-life conditions, by describing case reports and series published in the literature.

Methods

A literature search of all publications up to January 5th 2024 on the Medline and Embase databases was carried out. The results were presented both in the text and in tables.

Results

Sixty-seven case reports/series were included in this review, of which more than half related to alemtuzumab, natalizumab and ocrelizumab. The publication date of included studies ranged from 2006 to 2024. The majority of case reports and series described the occurrence of late-onset hematological disorders (events that occurred more than 30 days after the first DMT administration), mainly represented by case of neutropenia, autoimmune hemolytic anemia and immune thrombocytopenia. All cases reported a favorable outcome, apart one case report that described a fatal case. Among included cases, 4 articles, all related to natalizumab, described the occurrence of myeloid disorders in 13 newborns from mother receiving the DMT.

Discussion

Considering the limitations identified in the majority of included studies, further ad hoc studies are strongly needed to better evaluate the hematological disorders of DMTs. Meantime, the strict monitoring of treated patients for the occurrence of these toxicities should be highly recommended.

Investigation of the correlation between platelet antibodies and peripheral blood cytopenia in patients with hepatocellular carcinoma

The primary triggers that stimulate the body to generate platelet antibodies via immune mechanisms encompass events such as pregnancy, transplantation, and blood transfusion. Interestingly, our findings revealed that a subset of male patients with hepatocellular carcinoma (HCC), despite having no history of transplantation or blood transfusion, has shown positive results in platelet antibody screenings. This hints at the possibility that certain factors, potentially related to the tumor itself or its treatment, may affect antibody production. To delve the causes we initiated this study. We employed a case-control study approach to analyze potential influential factors leading to the positive results via univariate and multivariate regression analysis. We utilized Kendall's tau-b correlation to examine the relationship between the strength of platelet antibodies and peripheral blood cytopenia. Antitumor medication emerged as an independent risk factor for positive results in HCC patients, and the strength of platelet antibodies positively correlated with the severity of anemia and thrombocytopenia. Without history of blood transfusion, transplantation, pregnancy, those HCC patients underwent recent tumor medication therapy are experiencing peripheral erythrocytopenia or thrombocytopenia, for them platelet antibody screenings holds potential clinical value for prevention and treatment of complications like drug-immune-related anemia and/or bleeding.

An Updated Comprehensive Pharmacovigilance Study of Drug-Induced Thrombocytopenia Based on FDA Adverse Event Reporting System Data

Drug-induced thrombocytopenia (DIT) deserves both clinical and research attention for the serious clinical consequences and high prevalence of the condition. The current study aimed to perform a comprehensive pharmacovigilance analysis of DIT reported in the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) database, with a particular focus on drugs associated with thrombocytopenia events. A disproportionality analysis of DIT was conducted using reports submitted to FARES from January 2004 to December 2022. Both the information component (IC) and reporting odds ratio (ROR) algorithms were applied to identify an association between target drugs and DIT events. A total of 15,940,383 cases were gathered in FAERS, 168,657 of which were related to DIT events. The top 50 drugs ranked by number of cases and ranked by signal strength were documented. The top 5 drugs ranked by number of cases were lenalidomide (10,601 cases), niraparib (3726 cases), ruxolitinib (3624 cases), eltrombopag (3483 cases), and heparin (3478 cases). The top 5 drugs ranked by signal strength were danaparoid (ROR 37.61, 95%CI 30.46-46.45), eptifibatide (ROR 34.75, 95%CI 30.65-39.4), inotersen (ROR 34.00, 95%CI 29.47-39.23), niraparib (ROR 30.53, 95%CI 29.42-31.69), and heparin (ROR 28.84, 95%CI 27.76-29.97). The top 3 involved drug groups were protein kinase inhibitors, antimetabolites, and monoclonal antibodies and antibody-drug conjugates. The current comprehensive pharmacovigilance study identified more drugs associated with thrombocytopenia. Although the mechanisms of DIT have been elucidated for some drugs, others still require further investigation.

PD-1/PD-L1 inhibitor-induced immune thrombocytopenia: A pharmacovigilance study and systematic review

INTRODUCTION

Programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) immune checkpoint inhibitors (ICIs) are used for a variety of cancers and are associated with a risk of developing immune-related adverse events, most commonly dermatitis, colitis, hepatitis, and pneumonitis. Immune-mediated hematologic toxicities have been reported, but are less well-described in the literature. Immune thrombocytopenia (ITP) is a rare autoimmune, hematologic adverse event that has been reported with PD-1/PD-L1 inhibitors.

METHODS

We performed a retrospective observational analysis of the United States Food and Drug Administration Adverse Event Reporting System (FAERS) data. We searched for cases of ITP reported with exposure to PD-1/PD-L1 inhibitors from initial FDA approval for each agent to September 30, 2022. Disproportionality signal analysis was done by calculating the reporting odds ratio (ROR). Oxaliplatin was used as a positive control for sensitivity analysis as it is an anticancer therapy that has been associated with drug-induced ITP. A systematic review of the PubMed database was also conducted to identify published cases of PD-1/PD-L1 inhibitor-induced ITP.

RESULTS

There were 329 reports of ITP with ICIs in the FAERS database that were reviewed for a disproportionality signal, including atezolizumab (n = 27), durvalumab (n = 17), nivolumab (n = 160), and pembrolizumab (n = 125). The ROR was significant for atezolizumab (ROR 5.39, 95 % CI 3.69-7.87), avelumab (ROR 10.32, 95 % CI 4.91-21.69), durvalumab (ROR 7.91, 95 % CI 4.91-12.75), nivolumab (ROR 9.76, 95 % CI 8.34-11.43), and pembrolizumab (ROR 12.6, 95 % CI 10.55-15.06). In our systematic review, we summated 57 cases of ICI-induced ITP. Nivolumab and pembrolizumab had the most reported cases of ITP in the literature. Most cases reported (53 %) included ITP-directed therapies beyond corticosteroids for the management of ICI-induced ITP.

CONCLUSION

There is a significant reporting signal of ITP with several ICI agents. Clinicians should be aware of and monitor for signs of this potentially serious adverse event.

Accuracy of Diagnosing Heparin-Induced Thrombocytopenia

Importance

Heparin-induced thrombocytopenia (HIT) is a life-threatening condition that requires urgent diagnostic clarification. However, knowledge of the diagnostic utility of the recommended diagnostic tests is limited in clinical practice.

Objective

To evaluate the current diagnostic practice for managing the suspicion of HIT.

Design, Setting, and Participants

This prospective diagnostic study was conducted from January 2018 to May 2021 among consecutive patients with suspected HIT from 11 study centers in Switzerland, Germany, and the United States. Detailed clinical data and laboratory information were recorded. Platelet factor 4/heparin antibodies were quantified using an automated chemiluminescent immunoassay (CLIA). A washed-platelet heparin-induced platelet activation (HIPA) test was used as a reference standard to define HIT.

Exposures

Suspicion of HIT.

Main Outcomes and Measures

The primary outcome was the diagnostic accuracy of the 4Ts score, the CLIA, and the recommended algorithm serially combining both tests.

Results

Of 1448 patients included between 2018 and 2021, 1318 were available for the current analysis (median [IQR] age, 67 [57-75] years; 849 [64.6%] male). HIPA was positive in 111 patients (prevalence, 8.4%). The most frequent setting was intensive care unit (487 [37.0%]) or cardiovascular surgery (434 [33.0%]). The 4Ts score was low risk in 625 patients (46.8%). By 2 × 2 table, the numbers of patients with false-negative results were 10 (9.0%; 4Ts score), 5 (4.5%; CLIA), and 15 (13.5%; recommended diagnostic algorithm). The numbers of patients with false-positive results were 592 (49.0%; 4Ts score), 73 (6.0%; CLIA), and 50 (4.1%; recommended diagnostic algorithm), respectively.

Conclusions and Relevance

In this diagnostic study of patients suspected of having HIT, when the recommended diagnostic algorithm was used in clinical practice, antibody testing was required in half the patients. A substantial number of patients were, however, still misclassified, which could lead to delayed diagnosis or overtreatment. Development of improved diagnostic algorithms for HIT diagnosis should be pursued.

Delayed-onset eptifibatide-induced thrombocytopenia

PURPOSE

We present a unique case of delayed-onset, profound eptifibatide-induced thrombocytopenia that occurred 5 days after initiation of the drug.

SUMMARY

Eptifibatide is a platelet glycoprotein IIb/IIIa receptor inhibitor with indications for use in patients with acute coronary syndromes. Eptifibatide-induced thrombocytopenia is uncommon but well studied and typically occurs within 24 hours of initiation of the drug. In the case described here, a 62-year-old male with a past history of coronary artery disease (including percutaneous coronary intervention within the past 12 months) was started on eptifibatide at a dosage of 2 µg/kg per minute for management of significant thrombus burden prior to a planned cardiac revascularization procedure; heparin for anticoagulation was also initiated. About 5 days after initiation of eptifibatide, the patient developed severe thrombocytopenia, with the platelet count dropping precipitously from 249 × 103/µL on admission to less than 1 × 103/µL. After eptifibatide and heparin therapy were discontinued and the patient was switched to argatroban, the platelet count recovered to 38 × 103/µL over the next 2 days. An eptifibatide platelet antibody assay was positive for IgG-mediated reactions consistent with eptifibatide-induced thrombocytopenia. Scoring of this case with the Naranjo scale yielded a score of 4, suggesting a possible adverse reaction to eptifibatide.

CONCLUSION

This is the first published case report of profound eptifibatide-induced thrombocytopenia occurring more than 24 hours after eptifibatide initiation and serves to bring awareness that a delayed reaction can occur.

Sulfamethoxazole-trimethoprim for pneumocystis pneumonia prophylaxis, causes of discontinuation and thrombocytopenia observed during administration: A single-center retrospective study

INTRODUCTION

The development of pneumocystis pneumonia (PCP) has recently become a growing concern; thus, its prevention has become increasingly important. Sulfamethoxazole-trimethoprim (ST) is a cost-effective first-line and prophylactic treatment for PCP. However, ST administration criteria for PCP prophylaxis remain unclear and are often discontinued because of adverse events (AEs). In this study, we aimed to investigate the causes of ST discontinuation and the associated AEs using objective data.

METHODS

We retrospectively analyzed the data of 162 patients admitted to Kansai Medical University Hospital between January 2018 and December 2020, who received ST for PCP prophylaxis. We compared clinical characteristics, laboratory data, and incidence of AEs between ST non-discontinuation and ST discontinuation groups. Additionally, we divided the patients into non-developing and developing thrombocytopenia (≥ Grade 1) groups based on the investigation results.

RESULTS

No patients developed PCP while receiving ST. The most common causes of ST discontinuation were thrombocytopenia (37%), liver dysfunction (20%), and rash (18%). Multivariate analysis revealed thrombocytopenia (≥ Grade 1) as a factor significantly associated with ST discontinuation. Furthermore, we identified three factors correlated with thrombocytopenia (≥ Grade 1): age ≥50 years, lymphocyte count <1000/μL, and platelet count <180,000/μL.

CONCLUSIONS

Patients with the aforementioned factors are at higher risk of developing thrombocytopenia (≥ Grade 1) during ST administration for PCP prophylaxis. Therefore, platelet count monitoring is essential to enhance safety and efficacy of ST treatment. Nonetheless, further research is warranted to explore additional implications and interventions.

Reference guide for the diagnosis of adult primary immune thrombocytopenia, 2023 edition

Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by isolated thrombocytopenia due to accelerated platelet destruction and impaired platelet production. Diagnosis of ITP is still challenging because ITP has been diagnosed by exclusion. Exclusion of thrombocytopenia due to bone marrow failure is especially important in Japan because of high prevalence of aplastic anemia compared to Western countries. Hence, we propose a new diagnostic criteria involving the measurement of plasma thrombopoietin (TPO) levels and percentage of immature platelet fraction (RP% or IPF%); 1) isolated thrombocytopenia with no morphological evidence of dysplasia in any blood cell type in a blood smear, 2) normal or slightly increased plasma TPO level (< cutoff), 3) elevated RP% or IPF% (> upper limit of normal), and 4) absence of other conditions that potentially cause thrombocytopenia including secondary ITP. A diagnosis of ITP is made if conditions 1-4 are all met. Cases in which criterion 2 or 3 is not met or unavailable are defined as "possible ITP," and diagnosis of ITP can be made mainly by typical clinical course. These new criteria enable us to clearly differentiate ITP from aplastic anemia and other forms of hypoplastic thrombocytopenia and can be highly useful in clinical practice for avoiding unnecessary bone marrow examination as well as for appropriate selection of treatments.

High levels of PD-L1 on platelets of NSCLC patients contributes to the pharmacological activity of Atezolizumab

Several studies have associated platelets (PLTs) to NSCLC prognosis. To understand the role of PLTs in immunotherapy-treated patients, we used blood samples of NSCLC patients at different TNM stage. We found that PLTs count and the expression of PD-L1 (pPD-L1) were significantly higher in NSCLC patients at Stage IV than Stage I-III and healthy subjects. The presence of high pPD-L1 was associated to upregulated genes for the extracellular matrix organization and tumor immunosuppression. When patients' survival was correlated to the levels of pPD-L1, longer survival rate was observed, but not when progression disease occurred. The in vitro stimulation of pPD-L1 with Atezolizumab induced CXCL4 release, accompanied by higher levels of TGFβ at the time of drug resistance when the levels of CD16, CD32 and CD64 significantly increased. Leiden-clustering method defined the phenotype of PLTs which showed that the ezrin-radixin-moesin (ERM) family proteins, underlying the PD-L1 signalosome, were involved in high pPD-L1 and higher survival rate. These data imply that Stage IV NSCLC patients characterized by high pPD-L1 are associated with longer progression-free survival rate because the blockade of pPD-L1 by Atezolizumab avoids the exacerbation of a T cell-mediated immune-suppressive environment. pPD-L1 could be an easy-to-use clinical approach to predict ICI responsiveness.

Tirofiban-induced thrombocytopenia

Tirofiban is a small non-peptide ligand-mimetic Glycoprotein (GP) IIb/IIIa inhibitor which can reversibly bind to the arginine-glycine-aspartic acid (RGD) recognition site of GP IIb/IIIa to prevent platelet aggregation. It reduces the incidence of thrombotic cardiovascular events in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Although generally considered safe, tirofiban has been reported to be associated with thrombocytopenia in several case reports and clinical trials. The pathogenesis for this adverse reaction is not entirely understood, is thought to be due to immune-mediated reaction. This side effect caused by tirofiban is especially concerning given how frequently it is used in the practice of contemporary cardiovascular care. The present review provides an overview of the pathophysiology, clinical presentation, management, and risk factors associated with tirofiban-induced thrombocytopenia.

Adverse Drug Effect Profiles of Gp2b/3a Inhibitors: A Comparative Review of the Last Two Decades

ST-Elevation Myocardial Infarction and non-ST Elevation Myocardial Infarction belong to the acute coronary syndrome group of diseases. These conditions are characterized by the complete or partial blockage of one or several coronary arteries, resulting in myocardial injury or necrosis. Various medications are used in their treatment, with the most recent addition being Glycoprotein IIb/IIIa inhibitors. They work by hindering the activity of glycoprotein IIb/IIIa receptors, which, in turn, prevents the clumping of platelets. Some of the GpIIb/IIIa inhibitors available in this category include abciximab, tirofiban, eptifibatide, roxifiban, and orbofiban. With this comprehensive literature review, we aimed to explore the potential adverse effects of these medications and compare the three in terms of their side effects profile. We searched through PubMed and Google Scholar and pinpointed 13 articles aligned with our inclusion criteria: six articles utilized eptifibatide, four were related to abciximab, and three used tirofiban. In 85% of the cases, a severe drop in platelet count, reaching as low as 1000/μL, was reported. Additionally, several other side effects were noted: one case documented multiple bruising spots appearing around the patient's body, two cases reported diffuse alveolar hemorrhage, and one case described a cardiac tamponade resulting from hemorrhagic pericarditis. Our study highlights the crucial significance of keeping a watchful eye on and comprehending the potential drawbacks linked to these medications in cardiovascular treatment. The necessity of researching these medications and their side effects is also evident, as this will significantly enhance the quality of treatment provided.

Simultaneous hypersensitivity reactions to trimethoprim-sulfamethoxazole and amoxicillin-clavulanate in a dog

Antibiotics are known to be able to cause hypersensitivity reactions through various mechanisms. We present a case of drug-induced immune thrombocytopenia (DITP) and anaphylactic shock occurring simultaneously in a dog after the administration of two classes of antibiotics, namely trimethoprim-sulfamethoxazole (TMP-SMX) and amoxicillin-clavulanate (AMC). The patient recovered completely from DITP on discontinuation of TMP-SMX and the anaphylactic shock caused by AMC was treated with intensive care. DITP is a rare adverse drug reaction (ADR), and anaphylactic shock is a life-threatening ADR. This is the first case report of a dog manifesting two types of hypersensitivity reactions caused by two antibiotics.

First platelet transfusion refractoriness in a patient with acute myelocytic leukemia: A case report

BACKGROUND

Platelet transfusion is of great significance in the treatment of thrombocytopenia caused by myelosuppression during intensive chemotherapy in patients with acute leukemia. In recent years, with platelet transfusion increasing, ineffective platelet transfusion has become increasingly prominent. Generally speaking, platelet antibodies can be produced after repeated transfusion, thus rendering subsequent platelet transfusion ineffective. We report a case of first platelet transfusion refractoriness (PTR) in a patient with acute myelocytic leukemia (AML). Due to the rarity of such cases in clinical practice, there have been no relevant case reports so far.

CASE SUMMARY

A 51-year-old female patient attended the hospital due to throat pain and abnormal blood cells for 4 d. Her diagnosis was acute myelocytic leukemia [M2 type Fms related receptor tyrosine kinase 3, Isocitrate Dehydrogenase 1, Nucleophosmin 1, Neuroblastoma RAS viral oncogene homolog (+) high-risk group]. She was treated with "IA" (IDA 10 mg day 1-3 and Ara-C 0.2 g day 1-5) chemotherapy. When her condition improved, the patient was discharged from the hospital, instructed to take medicine as prescribed by the doctor after discharge, and returned to the hospital for further chemotherapy on time.

CONCLUSION

We report a rare case of first platelet transfusion failure in a patient with AML during induction chemotherapy, which may be related to the production of platelet antibodies induced by antibiotics and excessive tumor load. This also suggests that we should consider the influence of antibiotics when the rare situation of first platelet transfusion failure occurs in patients with AML. When platelet antibodies are produced, immunoglobulins can be used to block antibodies, thereby reducing platelet destruction. For patients with PTR, both immune and non-immune factors need to be considered and combined in clinical practice along with individualized treatment to effectively solve the problem.

Anti-tubercular therapy (ATT) induced thrombocytopenia: A systematic review

INTRODUCTION

Drug-induced thrombocytopenia is a known adverse event of several drugs. Antitubercular therapy (ATT) is rarely reported but important cause of thrombocytopenia. The present review aimed to understand the profile of thrombocytopenia caused by first-line ATT i.e. isoniazid, rifampicin, pyrazinamide, and ethambutol.

MATERIALS AND METHODS

We screened case reports, case series, and letter-to-editor from databases, like Pubmed/MEDLINE, Ovid, and EMBASE from 1970 to 2021. The PRISMA guidelines were followed in the present systematic review.

RESULTS

Categorical data were expressed as n (%) and quantitative data were expressed as median (IQR). After applying the inclusion/exclusion criteria, 17 case reports and 7 letters to the editor were selected for the present review. Rifampicin was most frequently associated with thrombocytopenia (65%). A median (IQR) drop to 20,000 (49,500) platelets/mm3 was observed. Anti-rifampicin associated antibodies and anti-dsDNA positivity were found in six studies. Except for two, all patients responded to symptomatic treatment.

DISCUSSION

ATT-induced thrombocytopenia can be life-threatening and require hospitalization. Clinicians should be aware of the association of ATT with thrombocytopenia and should take appropriate measures for patient management.

CONCLUSION

This review provides clinicians a comprehensive picture of adverse effects and their management in ATT induced thrombocytopenia.

Drug-induced thrombocytopenia in a patient with colorectal cancer: A case report

Drug-induced thrombocytopenia is an adverse reaction characterized by accelerated platelet destruction. The present study described a case of thrombocytopenia that occurred during treatment with panitumumab. A female patient aged 49 years with metastatic rectal adenocarcinoma was treated with 9 out of 12 cycles of therapy with the standard of care, 5-fluorouacil (5-FU), oxaliplatin and folic acid, in association with panitumumab. During cycle 10, the patient developed severe thrombocytopenia, so the therapy was adjusted to a lower dosage; however, during cycle 11, after administration of panitumumab and before administration of 5-FU or oxaliplatin, the patient again presented with severe thrombocytopenia, with a platelet count <2×109/l. Immunology test results were negative apart from anti-nucleus antibodies (titration, 1:160). Naranjo's algorithm was used to establish the relationship between the use of panitumumab and thrombocytopenia onset and a score of 6 ('probable') was found. The temporal link between the onset of symptoms and administration of therapy, the relapse of thrombocytopenia after re-administration of the drug during cycle 11 (positive rechallenge) and Naranjo score of 6 ('probable') are crucial elements for establishing the causal relationship and the probability that thrombocytopenia was related to the administration of panitumumab. The patient then underwent two cycles of therapy with 5-FU, folic acid and irinotecan, in association with bevacizumab, experiencing again the same adverse event. Treatment with monoclonal antibodies was suspended altogether in favor of a switch to trifluridine/tipiracil. No other serious adverse events were reported.

Bleeding Complications in Vancomycin-Induced Thrombocytopenia: A Real-world Postmarketing Pharmacovigilance Analysis

PURPOSE

Vancomycin and linezolid are first-line drugs used for the prophylaxis and treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. Vancomycin is well known as the best alternative drug when linezolid-induced thrombocytopenia occurs. However, several cases with vancomycin-induced thrombocytopenia, especially with bleeding complications, have been reported recently, which has attracted attention. The objective of this study is to assess the potential relevance between vancomycin and bleeding complications in thrombocytopenia.

METHODS

This is a real-world pharmacovigilance study conducted in October 2022 using the US Food and Drug Administration Adverse Event Reporting System (FAERS) database. We performed a disproportional analysis to assess the risk of bleeding complications in vancomycin-induced thrombocytopenia by calculating reporting odds ratios (RORs) and information components (ICs), with a weak signal defined as a lower limit of the IC 95% CI of 0 to 1.5, a middle signal defined as a lower limit of the IC 95% CI of 1.5 to 3.0, and a strong signal defined as a lower limit of the IC 95% CI of >3.0.

FINDINGS

There were 21,854 cases in the FAERS database that listed vancomycin as a suspected drug from quarter 1 of 2004 to quarter 2 of 2022. There were 800 cases of vancomycin-induced thrombocytopenia and 125 cases of bleeding complications in vancomycin-induced thrombocytopenia. Teicoplanin, tigecycline, and vancomycin (3 middle signals) were sequentially less associated with thrombocytopenia than linezolid (strong signal). However, bleeding complications in thrombocytopenia were significant associated with vancomycin (ROR = 9.641; 95% CI, 8.105-11.468; IC = 3.184; 95% CI, 2.929-3.440 [middle signal]), followed by linezolid (ROR = 9.350; 95% CI, 7.318-11.947; IC = 3.106; 95% CI, 2.745-3.466 [middle signal]), teicoplanin (ROR = 6.399; 95% CI, 2.869-14.272; IC = 2.059; 95% CI, 0.881-3.283 [weak signal]), and daptomycin (ROR = 2.784; 95% CI, 1.496-5.180; IC = 1.287; 95% CI, 0.374-2.201 [weak signal]). Tigecycline and daptomycin were the least likely anti-MRSA drug to cause thrombocytopenia (middle signal and weak signal, respectively) and bleeding complications in thrombocytopenia (no signal and weak signal, respectively). Middle signals of bleeding complication in vancomycin-induced thrombocytopenia were found in all group except those <45 to ≥80 years of age (weak signal).

IMPLICATIONS

Bleeding complications in thrombocytopenia were significantly associated with vancomycin use, and the risk was highest among all the anti-MRSA drugs. Physicians should be aware of this possible serious adverse reaction.

Vancomycin-Induced Thrombocytopenia in a 35-Year-Old Female With Pneumonia: A Case Report

Vancomycin is one of the most empirically used antibiotics in severely ill patients in hospitalized settings. Vancomycin-induced thrombocytopenia (VITP) is a rare and potentially life-threatening complication that requires immediate recognition. Platelet destruction is largely immune-mediated and results in a precipitous drop in the platelet count over a short period of time. Most cases of VITP are drug-dependent, as discontinuation of the offending agent frequently results in a timely return to baseline to pre-exposure platelet levels. Here, we present a case of severe vancomycin-induced thrombocytopenia in a 35-year-old female with a history of multiple comorbidities who presented with pneumonia. She was undergoing treatment with vancomycin and piperacillin-tazobactam and developed thrombocytopenia within 24 hours of hospitalization. The patient was on a loading dose of 1250 mg intravenous vancomycin every 24 hours and piperacillin-tazobactam 3.375 g intravenously every six hours for presumed community-acquired pneumonia. Her other medications included ondansetron, bupropion, sertraline, tamsulosin, pantoprazole, ergocalciferol, and insulin glargine. Additionally, the patient was placed on a prophylactic dose of enoxaparin while in-patient. The patient's thrombocytopenia resolved with discontinuation of vancomycin. Clinicians should be well-informed about which medications can trigger thrombocytopenia whenever starting a medication in such cases.

Sulperazon-induced acute reactive thrombocytopenia during treatment of systemic lupus erythematosus: a case report

The purpose of this study is to report a patient who developed acute reactive thrombocytopenia while undergoing treatment with sulperazon for systemic lupus erythematosus (SLE). Sulperazon is a broad-spectrum antibiotic that can act against a wide range of microorganisms, but rarely causes severe thrombocytopenic events. We describe a 62-year-old man with new-onset acute reactive thrombocytopenia who experienced a precipitous fall in the platelet count from 168×109/L to 1×109/L within 29 hours after exposure to sulperazon. Sulperazon was immediately discontinued followed by administration of intravenous immunoglobulin for six consecutive days. The platelet count eventually recovered and petechiae at the injection sites improved. No complications secondary to acute reactive thrombocytopenia were observed except petechiae.

Drug-Induced Thrombocytopenia: A Case Involving Vancomycin

Drug-induced thrombocytopenia (DIT) is a rare adverse effect that occurs when administering various medications. The medications associated with this possible adverse effect include heparin, penicillin, furosemide, vancomycin, non-steroidal anti-inflammatory drugs, ranitidine, and many others. DIT causes a rapid decrease in platelet counts after drug administration and typically resolves once the offending agent has been discontinued. The induced thrombocytopenia increases the bleeding risk and possibility of adverse effects throughout a hospital course. In this case report, we look at the presenting symptoms and treatment course of an interesting case of DIT that occurred following the administration of vancomycin.

Drug-Induced Thrombocytopenia Due to Nintedanib during Treatment of Idiopathic Pulmonary Fibrosis

Nintedanib is a tyrosine kinase inhibitor that was approved for the treatment of patients with idiopathic pulmonary fibrosis in 2014. The most common side effect of Nintedanib is diarrhea, and thrombocytopenia is a rare side effect of Nintedanib. The exact mechanism is unknown, and the literature lacks case reports of this phenomenon. Here, we report the case of a patient who developed thrombocytopenia 12 weeks after starting treatment with Nintedanib. The patient underwent an extensive work up for infectious, hematological, autoimmune, and neoplastic diseases. The patient's thrombocytopenia resolved following cessation of Nintedanib. This case is significant as it reports a rare side effect that might have detrimental consequences if not recognized and treated timely. Additionally, the onset of thrombocytopenia was delayed, 3 months after the initiation of Nintedanib. We also highlight the various literature regarding drug-induced thrombocytopenia and explore the necessary work-up needed to exclude other potential diagnoses. We hope to advocate for multidisciplinary teams to be aware of patients with pulmonary fibrosis on Nintedanib so that this adverse effect can be recognized promptly.

Case report: reuse of tirofiban leads to very severe thrombocytopenia

Background

Telofiban is a class of small molecule non-peptide tyrosine derivatives containing RGD sequences. It is the only platelet surface glycoprotein (GP) IIb/IIIa receptor antagonist (GPI) currently marketed in China. In patients with ST-segment elevation myocardial infarction(STEMI) who receive percutaneous coronary intervention (PCI) with a heavy thrombotic load, postoperative intravenous tirofiban can prevent complications of myocardial ischemia due to sudden coronary artery occlusion. With the increase in the clinical use of tirofiban, the number of adverse reactions related to thrombocytopenia induced by tirofiban has gradually increased. Still, most of them have thrombocytopenia after the first use. We report one case of very severe thrombocytopenia following the reuse of tirofiban.

Case summary

A 65-year-old man of Han nationality, 170 cm in height, 85 kg in weight, and 29.4 BMI, suffered from cerebral infarction 13 years ago and left with right limb movement disorder. Five days before this hospitalization, the patient underwent PCI, and three stents were implanted. After the operation, anti-platelet tirofiban and nadroparin calcium were given, and no thrombocytopenia was found. The patient still retains 80% stenosis due to anterior descending branches and plans to undergo PCI again half a month later. The patient with a history of hypertension, type 2 diabetes, diabetic nephropathy, and cerebral infarction usually took 100 mg of aspirin and 75 mg of clopidogrel, antiplatelet therapy, and had no history of food and drug allergy. One day after discharge, the patient suddenly felt chest tightness and wheezing. The laboratory showed hypersensitivity troponin 2.85 ng/ml (normal 0-0.0268 ng/ml), and the admission ECG showed ST-T changes in leads I, aVL, V5-V6. On the 6th day of hospitalization, PCI was performed, a stent was implanted in the proximal section of the anterior descending branch opening, and tirofiban(10 ug/kg, 3 min bolus, then 0.1 ug/kg/min) antiplatelet therapy was given after surgery. About 10 min after the tirofiban infusion, the patient suddenly shivered, accompanied by convulsions, accompanied by elevated body temperature (up to 39.4°C), accompanied by epistaxis and microscopic hematuria. An urgent blood test showed that the platelets dropped to 1 × 109/L, tirofiban and aspirin stopped immediately, and the antiplatelet therapy of clopidogrel was retained. After infusion of methylprednisolone sodium succinate and gamma globulin, the patient's platelets gradually recovered, and the patient was successfully discharged seven days later in stable condition.

Conclusion

This case is typical of severe thrombocytopenia caused by reusing tirofiban. This case may provide new insights into: 1. Patients who did not have thrombocytopenia after the first use of tirofiban may still have extremely severe thrombocytopenia after re-exposure to tirofiban. Routine platelet count monitoring and early identification of thrombocytopenia are the essential links. 2. Thrombocytopenia caused by re-exposure to tirofiban may have a faster onset, deeper degree, and slower recovery due to antibodies retained after the first exposure to tirofiban; 3. Platelet transfusions may not be necessary for patients with severe thrombocytopenia; 4. Immunosuppressants help suppress the body's immune response, promote platelet recovery, and can be reduced or discontinued when platelets rise and may be safe; 5. After tirofiban for PCI, continuing the maintenance dose of clopidogrel may be safe if the patient has no significant bleeding events.

Severe Acute Thrombocytopenia After Treatment with Tirofiban: A Case Series Approach

Glycoprotein IIb/IIIa inhibitors are an adjuvant therapy for the treatment of patients with acute coronary syndromes. The main adverse reactions are bleeding and thrombocytopenia in 1-2% of cases. A 66-year-old woman arrived at the emergency department with ST-elevation MI. The catheterisation lab was busy, so she received thrombolytic therapy. Coronary angiography revealed a 90% stenosis in the middle segment of the left anterior descending artery and Thrombolysis in MI 2 flow. Subsequent percutaneous coronary intervention showed abundant thrombus and a coronary dissection and it was necessary to insert five drug-eluting stents. Non-fractionated heparin and a tirofiban infusion were used. After the percutaneous coronary intervention, she developed severe thrombocytopenia, haematuria and gingivorrhagia, for which infusion of tirofiban was suspended. In follow-up, no major bleeding or subsequent haemorrhagic complications were identified. It is crucial to distinguish between heparin-induced thrombocytopenia and thrombocytopenia caused by other drugs. A high level of suspicion should be employed in these cases.

A Case of Vancomycin-Induced Severe Immune Thrombocytopenia

A male in his 60s presented with left lower extremity fractures following a vehicle accident. Hemoglobin, initially, was 12.4 mmol/L, and platelet count was 235 k/mcl. On day 11 of admission, his platelet count initially dropped to 99 k/mcl, and after recovery it rapidly decreased to 11 k/mcl on day 16 when the INR was 1.3 and aPTT was 32 s, and he continued to have a stable anemia throughout admission. There was no response in platelet count post-transfusion of four units of platelets. Hematology initially evaluated the patient for disseminated intravascular coagulation, heparin-induced thrombocytopenia (anti-PF4 antibody was 0.19), and thrombotic thrombocytopenic purpura (PLASMIC score of 4). Vancomycin was administered on days 1-7 for broad spectrum antimicrobial coverage and day 10, again, for concerns of sepsis. Given the temporal association of thrombocytopenia and vancomycin administration, a diagnosis of vancomycin-induced immune thrombocytopenia was established. Vancomycin was discontinued, and 2 doses of 1000 mg/kg of intravenous immunoglobulin 24 h apart were administered with the subsequent resolution of thrombocytopenia.

Significance of Oral Manifestations in the Diagnosis of Severe Phenytoin-Induced Thrombocytopenia: A Rare Case

Phenytoin is a commonly used anticonvulsant drug for the prophylaxis of generalized tonic-clonic seizures, partial seizures, and neurosurgery-related seizure prevention. Phenytoin-induced thrombocytopenia is a rare but life-threatening condition. Close monitoring of blood counts may be necessary for patients receiving phenytoin, as delay in diagnosis or withdrawal of the drug can be life-threatening. Clinical manifestations of phenytoin-induced thrombocytopenia are usually reported within one to three weeks after drug initiation. In this article, we report a unique case of drug-induced thrombocytopenia that manifested as multiple hemorrhagic lesions in the oral mucous membrane three months after phenytoin initiation.

Applications of Artificial Intelligence in Thrombocytopenia

Thrombocytopenia is a medical condition where blood platelet count drops very low. This drop in platelet count can be attributed to many causes including medication, sepsis, viral infections, and autoimmunity. Clinically, the presence of thrombocytopenia might be very dangerous and is associated with poor outcomes of patients due to excessive bleeding if not addressed quickly enough. Hence, early detection and evaluation of thrombocytopenia is essential for rapid and appropriate intervention for these patients. Since artificial intelligence is able to combine and evaluate many linear and nonlinear variables simultaneously, it has shown great potential in its application in the early diagnosis, assessing the prognosis and predicting the distribution of patients with thrombocytopenia. In this review, we conducted a search across four databases and identified a total of 13 original articles that looked at the use of many machine learning algorithms in the diagnosis, prognosis, and distribution of various types of thrombocytopenia. We summarized the methods and findings of each article in this review. The included studies showed that artificial intelligence can potentially enhance the clinical approaches used in the diagnosis, prognosis, and treatment of thrombocytopenia.

Psychiatric medications and the risk of autoimmune and immune-mediated inflammatory diseases: A systematic review and meta-analysis of observational studies

BACKGROUND

Pharmacovigilance reports have suggested that certain commonly used medications may trigger autoimmune diseases (ADs) and immune-mediated inflammatory diseases (IMIDs). We systematically reviewed the literature to evaluate whether psychiatric medication use is associated with ADs and IMIDs.

METHODS

The protocol was registered in PROSPERO (CRD42022296524) before the start of the study. We searched Medline Ovid and Scopus up to November 28th, 2021, for comparative studies, with any psychiatric medication as exposure and ADs and IMIDs as outcomes. Meta-analysis was performed using DerSimonian-Laird random-effects modeling. The PRISMA 2020 guidelines were followed in reporting. Study-level risk of bias was assessed using the Newcastle-Ottawa Scale, and the overall certainty of evidence using GRADE.

RESULTS

There were 7,265 citations from which 31 studies were eligible, all from high-income countries, covering 15 distinct immune diseases. The evidence for the association between selective serotonin reuptake inhibitor (SSRI) use and higher risk of microscopic colitis (meta-OR 2.60, 95% CI 1.05-6.39, I2 97.5%, 6 studies) was of low certainty. A subgroup analysis by the histological type of microscopic colitis showed a statistically significant association only with lymphocytic colitis (meta-OR 2.88, 95% CI 2.60-3.18, I2 00.00%, three studies). In two case-control studies, SSRI use had no significant association with psoriasis (meta-OR 0.80, 95% CI 0.58-1.10, I2 82.4%). The risk of acute pancreatitis was slightly increased with exposure to SSRIs (meta-OR 1.13, 95% CI 1.01-1.26, I2 00.0%), as was the risk of bullous pemphigoid after exposure to antipsychotics (meta-OR 1.79, 95% CI 1.17-2.73, I2 0%).

CONCLUSIONS

We reviewed the literature on whether psychiatric medications associate with the risk of ADs and IMIDs and concluded that, despite several signals, the credibility of evidence remains low at best. Prospective cohort studies would be needed as the next step to confirm the suggestions of increased risk.

Scoping Review on Epigenetic Mechanisms in Primary Immune Thrombocytopenia

Immune Thrombocytopenia (ITP) is an autoimmune blood disorder that involves multiple pathways responsible for the homeostasis of the immune system. Numerous pieces of literature have proposed the potential of immune-related genes as diagnostic and prognostic biomarkers, which mostly implicate the role of B cells and T cells in the pathogenesis of ITP. However, a more in-depth understanding is required of how these immune-related genes are regulated. Thus, this scoping review aims to collate evidence and further elucidate each possible epigenetics mechanism in the regulation of immunological pathways pertinent to the pathogenesis of ITP. This encompasses DNA methylation, histone modification, and non-coding RNA. A total of 41 studies were scrutinized to further clarify how each of the epigenetics mechanisms is related to the pathogenesis of ITP. Identifying epigenetics mechanisms will provide a new paradigm that may assist in the diagnosis and treatment of immune thrombocytopenia.

Older Adults and Immune Thrombocytopenia: Considerations for the Clinician

Many epidemiological studies have shown that the incidence of immune thrombocytopenia (ITP) increases after age 60 years and peaks in patients over age 80 years. Therefore, ITP is a concern for physicians taking care of older patients, especially regarding its diagnosis and management. The diagnostic work-up should exclude other causes of thrombocytopenia and secondary ITP, including myelodysplastic syndrome and drug-induced ITP. The treatment decision is influenced by an increased risk of bleeding, infectious diseases and thrombosis in this population and should take into account comorbidities and concomitant medications such as anticoagulant drugs. First-line treatment is based on short corticosteroids courses and intravenous immunoglobulin, which should be reserved for patients with more severe bleeding complications, with their higher risk of toxic effects as compared with younger patients. Second-line treatment should be tailored to the patient's history, comorbidities and preferences. Preferred second-line treatments are thrombopoietin receptor agonists for most groups and guidelines given their good efficacy/tolerance ratio, but the thrombotic risk is increased in older people. Other second-line options that can be good alternatives depending on the clinical context include rituximab, dapsone, fostamatinib or immunosuppressive drugs. Splenectomy is less often performed but remains an option for fit patients with chronic refractory disease. Emerging treatments such as Syk or Bruton tyrosine kinase inhibitors and FcRn antagonists are becoming available for ITP and may modify the treatment algorithm in the near future. The aim of this review is to describe the particularities of the diagnosis and treatment of ITP in older people, including the response and tolerance to the currently available drugs. We also discuss some situations related to co-morbidities that can frequently lead to adapt the management strategy in older patients.

A case of severe thrombocytopenia after the first exposure to rifampicin

Severe immune thrombocytopenia is a rare side-effect of rifampicin (RFP) and can be life-threatening. Here, we report the case of a 74-year-old male with tuberculous pleurisy who developed severe thrombocytopenia after first exposure to RFP. Platelet count decreased to 1 × 10³/μL after 7 days of treatment with RFP, isoniazid, ethambutol, and pyrazinamide. After all the drugs were discontinued, the platelet count recovered. As thrombocytopenia did not occur after re-administration of drugs other than RFP, the patient was diagnosed with RFP-induced thrombocytopenia. Clinicians should be aware that RFP can induce acute and severe thrombocytopenia even without previous exposure to this drug.

Hypersensitivity reactions to small molecule drugs

Drug hypersensitivity reactions induced by small molecule drugs encompass a broad spectrum of adverse drug reactions with heterogeneous clinical presentations and mechanisms. These reactions are classified into allergic drug hypersensitivity reactions and non-allergic drug hypersensitivity reactions. At present, the hapten theory, pharmacological interaction with immune receptors (p-i) concept, altered peptide repertoire model, and altered T-cell receptor (TCR) repertoire model have been proposed to explain how small molecule drugs or their metabolites induce allergic drug hypersensitivity reactions. Meanwhile, direct activation of mast cells, provoking the complement system, stimulating or inhibiting inflammatory reaction-related enzymes, accumulating bradykinin, and/or triggering vascular hyperpermeability are considered as the main factors causing non-allergic drug hypersensitivity reactions. To date, many investigations have been performed to explore the underlying mechanisms involved in drug hypersensitivity reactions and to search for predictive and preventive methods in both clinical and non-clinical trials. However, validated methods for predicting and diagnosing hypersensitivity reactions to small molecule drugs and deeper insight into the relevant underlying mechanisms are still limited.

Hematologic cytopenia post CAR T cell therapy: Etiology, potential mechanisms and perspective

Chimeric Antigen-Receptor (CAR) T-cell therapies have shown dramatic efficacy in treating relapsed and refractory cancers, especially B cell malignancies. However, these innovative therapies cause adverse toxicities that limit the broad application in clinical settings. Hematologic cytopenias, one frequently reported adverse event following CAR T cell treatment, are manifested as a disorder of hematopoiesis with decreased number of mature blood cells and subdivided into anemia, thrombocytopenia, leukopenia, and neutropenia, which increase the risk of infections, fatigue, bleeding, fever, and even fatality. Herein, we initially summarized the symptoms, etiology, risk factors and management of cytopenias. Further, we elaborated the cellular and molecular mechanisms underlying the initiation and progression of cytopenias following CAR T cell therapy based on previous studies about acquired cytopenias. Overall, this review will facilitate our understanding of the etiology of cytopenias and shed lights into developing new therapies against CAR T cell-induced cytopenias.

Latamoxef-induced severe thrombocytopenia during the treatment of pulmonary infection: A case report

BACKGROUND

Latamoxef shows excellent antibacterial activity against anaerobic bacteria such as Bacteroides fragilis. Reports of thrombocytopenic toxicity of latamoxef are limited. This report presents a case of severe thrombocytopenia possibly induced by latamoxef, an infrequent adverse drug reaction in a young patient with tuberculosis and Crohn's disease in China.

CASE SUMMARY

We reported a case of severe thrombocytopenia induced by latamoxef in a 28-year-old man with tuberculosis and Crohn's disease. On admission, the patient presented with a cough productive of bloody sputum, a chest computed tomogram suggested scattered mottled, high-density shadows in both lungs. Laboratory tests indicated a platelet count of 140000/μL. Considered a pulmonary bacterial infection, the patient received anti-infection therapy with latamoxef (dose: 2.0 g) intravenously Q12h. On the 9^th day of treatment, the platelet count decreased to 44000/μL. On the 12^th day, scattered purpura and ecchymosis appeared on the patient’s limbs and trunk, and the platelet count decreased to 9000/μL after latamoxef treatment for 15 d. Three days after discontinuation of latamoxef, the platelet count recovered to 157000/μL, and the area of scattered purpura and ecchymosis on the limbs and trunk decreased. The platelet counts remained in the normal range, and no thrombocytopenia was found at follow-up 15 mo after discharge.

CONCLUSION

For patients treated with latamoxef, platelet counts should be carefully followed, and caregivers should be vigilant for the appearance of scattered ecchymosis.

Linezolid vs Vancomycin in Induced Thrombocytopenia

INTRODUCTION

Linezolid and vancomycin have an important place among therapeutic antimicrobial options for multidrug-resistant gram-positive infections. Thrombocytopenia is an adverse effect reported with both and can lead to treatment interruption. Our objective was to compare the incidence of thrombocytopenia in patients receiving linezolid or vancomycin and to identify risk factors associated with thrombocytopenia.

METHODS

This was a retrospective observational cohort study that involved patients who received linezolid (intravenously or orally) or vancomycin (intravenously) at a tertiary care hospital, between January 2016 and October 2019, for a minimum of 5 days and in whom platelet values were measured during treatment. Data on platelet count were collected during therapy in each group to identify the incidence of thrombocytopenia.

RESULTS

A total of 453 patients fulfilled the study criteria; 241 patients received linezolid and 212 patients vancomycin. The main logistic regression analysis revealed that patients in the linezolid group had approximately a four times higher incidence of thrombocytopenia (OR 4.39; 95% CI 2.38-8.08) compared to vancomycin. An increased incidence of thrombocytopenia was associated with advanced age, baseline platelet count and vasopressor use.

CONCLUSION

Clinicians considering vancomycin or linezolid for a susceptible infection should weigh the higher risk of thrombocytopenia that may be observed with linezolid vs. vancomycin in their decision.

Furosemide-Induced Thrombotic Thrombocytopenic Purpura: A Report of a Rare Case

Drug-induced immune thrombocytopenia (DITP) refers to drug-dependent, antibody-mediated platelet destruction. Although several drugs have been implicated as the cause of DITP, the most commonly encountered are heparin, sulfonamides, quinine, vancomycin, and beta-lactam antibiotics. However, furosemide has been rarely reported as the cause of thrombocytopenia. We present a unique case of furosemide-induced thrombotic thrombocytopenia in a 64-year-old female referred by her primary care provider for low platelets, rash, and bleeding. She was recently started on oral furosemide for diastolic heart failure two weeks before this presentation. She was admitted to the intensive care unit and was worked up for new-onset thrombocytopenia. Labs revealed anemia, thrombocytopenia, elevated lactate dehydrogenase, and low haptoglobin with normal serum creatinine. Peripheral smear showed schistocytes, low platelets, and ADAMTS13 level was 0.03. The patient was diagnosed with thrombotic thrombocytopenic purpura and treated with steroids, rituximab, and plasmapheresis, which led to rapid recovery of the platelet count to normal. Based on this case report, clinicians should consider furosemide as one of the drugs potentially causing thrombotic thrombocytopenia. Early detection and prompt management can be lifesaving.

Association of platelet count with mortality in patients with infectious diseases in intensive care unit: a multicenter retrospective cohort study

Platelets play important roles in thrombosis, hemostasis, inflammation, and infection. We aimed to evaluate the association between platelet count and its variation trend and prognosis of patient with infectious diseases in intensive care units (ICUs). This retrospective cohort study extracted 4,251 critically ill adult patients with infectious diseases from the eICU Collaborative Research Database, whose platelet counts were measured daily during the first 7 days after admission. In the survivors, platelet counts decreased in the first days after admission, reached a nadir on day 3, and then returned and continued to rise above the admission value. In non-survivors, the platelet counts decreased after admission, without a subsequent upturn. We defined three subgroups according to the nadir platelet counts within 7 days: ≤50, 50-130, and ≥130 × 10⁹/L, corresponding to high, intermediate, and low ICU mortality. A decreased platelet count was associated with increased ICU mortality (intermediate vs. low: 1.676 [1.285-2.187]; high vs. low: 3.632 [2.611-5.052]). In conclusion, during the first 7 days, platelet counts decreased after ICU admission, while increased subsequently in the survivors but not in the non-survivors. ICU mortality risk increased as nadir platelet count decreased below 130 × 10⁹/L, and further boosted when it reached below 50 × 10⁹/L.

Drug-Induced Immune Thrombocytopenia Toxicity Prediction Based on Machine Learning

Drug-induced immune thrombocytopenia (DITP) often occurs in patients receiving many drug treatments simultaneously. However, clinicians usually fail to accurately distinguish which drugs can be plausible culprits. Despite significant advances in laboratory-based DITP testing, in vitro experimental assays have been expensive and, in certain cases, cannot provide a timely diagnosis to patients. To address these shortcomings, this paper proposes an efficient machine learning-based method for DITP toxicity prediction. A small dataset consisting of 225 molecules was constructed. The molecules were represented by six fingerprints, three descriptors, and their combinations. Seven classical machine learning-based models were examined to determine an optimal model. The results show that the RDMD + PubChem-k-NN model provides the best prediction performance among all the models, achieving an area under the curve of 76.9% and overall accuracy of 75.6% on the external validation set. The application domain (AD) analysis demonstrates the prediction reliability of the RDMD + PubChem-k-NN model. Five structural fragments related to the DITP toxicity are identified through information gain (IG) method along with fragment frequency analysis. Overall, as far as known, it is the first machine learning-based classification model for recognizing chemicals with DITP toxicity and can be used as an efficient tool in drug design and clinical therapy.

Risk Assessment in Drug Hypersensitivity: Detecting Small Molecules Which Outsmart the Immune System

Drug hypersensitivity (DH) reactions are clinically unusual because the underlying immune stimulations are not antigen-driven, but due to non-covalent drug-protein binding. The drugs may bind to immune receptors like HLA or TCR which elicits a strong T cell reaction (p-i concept), the binding may enhance the affinity of antibodies (enhanced affinity model), or drug binding may occur on soluble proteins which imitate a true antigen (fake antigen model). These novel models of DH could have a major impact on how to perform risk assessments in drug development. Herein, we discuss the difficulties of detecting such non-covalent, labile and reversible, but immunologically relevant drug-protein interactions early on in drug development. The enormous diversity of the immune system, varying interactions, and heterogeneous functional consequences make it to a challenging task. We propose that a realistic approach to detect clinically relevant non-covalent drug interactions for a new drug could be based on a combination of in vitro cell culture assays (using a panel of HLA typed donor cells) and functional analyses, supplemented by structural analysis (computational data) of the reactive cells/molecules. When drug-reactive cells/molecules with functional impact are detected in these risk assessments, a close clinical monitoring of the drug may reveal the true incidence of DH, as suppressing but also enhancing factors occurring in vivo can influence the clinical manifestation of a DH.

The important role of non-covalent drug-protein interactions in drug hypersensitivity reactions

Drug hypersensitivity reactions (DHR) are heterogeneous and unusual immune reactions with rather unique clinical presentations. Accumulating evidence indicates that certain non-covalent drug-protein interactions are able to elicit exclusively effector functions of antibody reactions or complete T-cell reactions which contribute substantially to DHR. Here, we discuss three key interactions; (a) mimicry: whereby soluble, non-covalent drug-protein complexes ("fake antigens") mimic covalent drug-protein adducts; (b) increased antibody affinity: for example, in quinine-type immune thrombocytopenia where the drug gets trapped between antibody and membrane-bound glycoprotein; and (c) p-i-stimulation: where naïve and memory T cells are activated by direct binding of drugs to the human leukocyte antigen and/or T-cell receptors. This transient drug-immune receptor interaction initiates a polyclonal T-cell response with mild-to-severe DHR symptoms. Notable complications arising from p-i DHR can include viral reactivations, autoimmunity, and multiple drug hypersensitivity. In conclusion, DHR is characterized by abnormal immune stimulation driven by non-covalent drug-protein interactions. This contrasts DHR from "normal" immunity, which relies on antigen-formation by covalent hapten-protein adducts and predominantly results in asymptomatic immunity.

Assessment and Management of Immune Thrombocytopenia (ITP) in the Emergency Department: Current Perspectives

Immune thrombocytopenia (ITP) is characterized by a platelet count less than 100 × 10^9/L without anemia or leukopenia. Patients with ITP may be asymptomatic, or they may have mild bleeding like petechiae, purpura, or epistaxis. In rare cases, they may present to the emergency department (ED) with life-threatening bleeding as a result of their thrombocytopenia. The emergency physician should thus be prepared to diagnose ITP and treat the bleeding that can result from it. The diagnosis of ITP requires excluding secondary causes of thrombocytopenia, and in the ED, the bare minimum workup for ITP includes a complete blood count and a peripheral blood smear. The peripheral blood smear should show a small number of large platelets with normal morphology, and there should not be an increased number of schistocytes. Many patients with ITP require no emergent treatment. However, if a patient with suspected ITP presents to the ED with critical hemorrhage, the emergency physician should initiate treatment with a platelet transfusion, corticosteroids, and intravenous immune globulin (IVIG) as soon as possible. For less severe bleeding, platelet transfusions are not recommended, and the treatment consists of corticosteroids by themselves or in conjunction with IVIG.

COVID-19-A Trigger Factor for Severe Immune-Mediated Thrombocytopenia in Active Rheumatoid Arthritis

Thrombocytopenia is defined as a platelet count below 150,000/mm³ for adults. There is still controversy about whether individuals with platelet counts of 100,000/mm³ to 150,000/mm³ should be classified as having genuine thrombocytopenia or borderline thrombocytopenia. Thrombocytopenia is considered mild when the platelet count is between 70,000 and 150,000/mm³ and severe if the count is less than 20,000/mm³. Thrombocytopenia in rheumatoid arthritis is a rare complication, with an incidence estimated between 3 and 10%. The main etiological aspects include drug-induced thrombocytopenia and immune thrombocytopenic purpura. The most common hematological abnormalities in SARS-CoV-2 infection are lymphopenia and thrombocytopenia. It has been observed that the severity of thrombocytopenia correlates with the severity of the infection, being a poor prognosis indicator and a risk factor for mortality. COVID-19 can stimulate the immune system to destroy platelets by increasing the production of autoantibodies and immune complexes. Autoimmunity induced by viral infections can be related to molecular mimicry, cryptic antigen expression and also spreading of the epitope. During the COVID-19 pandemic, it is of great importance to include the SARS-CoV-2 infection in differential diagnoses, due to the increased variability in forms of presentation of this pathology. In this review, our aim is to present one of the most recently discovered causes of thrombocytopenia, which is the SARS-CoV-2 infection and the therapeutic challenges it poses in association with an autoimmune disease such as rheumatoid arthritis.