Drug-induced immune thrombocytopenia

A Case of Severe Thrombocytopenia, Aseptic Meningitis, and Hepatitis Caused by Trimethoprim-Sulfamethoxazole: A Triple Threat

Trimethoprim-sulfamethoxazole (TMP-SMX), a widely used antibiotic, is associated with both predictable dose-dependent side effects and rare, idiosyncratic adverse reactions. Here, we report the case of a previously healthy, non-G6PD-deficient, 27-year-old male who developed three idiosyncratic reactions: severe thrombocytopenia, aseptic meningitis, and hepatitis concurrently following TMP-SMX administration. The Naranjo adverse reaction probability score was 7, implying TMP-SMX as the probable cause of the clinical presentation. After a comprehensive workup to rule out alternate etiologies, we have established TMP-SMX as the culprit. Our case highlights the importance of early recognition of TMP-SMX-induced rare adverse events for appropriate management to mitigate long-term sequelae and ensure favorable patient outcomes.

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.

How I diagnose and treat thrombocytopenia in geriatric patients

ABSTRACT

Thrombocytopenia in older individuals is a common but diagnostically challenging condition that has variable clinical impact to those who are affected. Diagnostic approach requires evaluation of the preexisting clinical conditions, detailed review of medications, and assessment for disorders that warrant urgent treatment. In this article, we describe a systematic approach to diagnosis of thrombocytopenia and present a schematic review for management strategies. Three clinical scenarios are presented that are relevant for their prevalence and management challenges in an older adult population. The first scenario addresses primary immune thrombocytopenia (ITP) and reviews different treatment options. The second one addresses complications of thrombocytopenia in management of the myelodysplastic syndrome. The last one reviews diagnostic challenges of drug-induced ITP.

Clinical Manifestations and Risk Factors of Tigecycline-Associated Thrombocytopenia

Background

Thrombocytopenia, characterized by a diminished platelet count, emerged as the most frequently reported coagulation dysfunction event according to the FDA Adverse Event Reporting System (FAERS) database. In recent years, numerous clinical studies have investigated the potential link between tigecycline usage and the occurrence of hypofibrinogenemia. However, a research gap remains in comprehensively examining the association between tigecycline and thrombocytopenia in real-world settings.

Methods

This study was conducted to explore the incidence and clinical manifestations of tigecycline-associated thrombocytopenia. A retrospective case-control study of patients treated with tigecycline was conducted between January 2018 and June 2022.

Results

In total, 373 patients were included in this study. Among these patients, 12.3% experienced thrombocytopenia. The onset of thrombocytopenia occurred within a range of 2 to 22 days after the initiation of tigecycline, with a median period (25-75th percentile) of 9 (6-11) days. Among the patients manifesting thrombocytopenia, 60.9% exhibited mild-to-moderate cases (grades 1-2) while 39.1% endured severe cases (grades 3-4). Multivariate analysis delineated several factors as independent risk factors for thrombocytopenia. Notably, advanced age (≥74 years) (p=0.028), risk of malnutrition (p<0.001), tigecycline therapy for ≥7 days (p=0.003), DBIL>8.1μmol/L (p<0.001)), BUN>8.1mmol/L (p=0.002) emerged as independent risk factors associated with thrombocytopenia. When comparing the control group to the thrombocytopenia group, 70.7% of patients in the control group exhibited 0-2 risk factors, while all patients in the thrombocytopenia group demonstrated risk factors. Specifically, 95.7% of patients in the thrombocytopenia group presented with three to five risk factors, with only 4.4% having 0-2 risk factors.

Conclusion

Tigecycline administration is associated with thrombocytopenia. Healthcare professionals should exercise vigilance, particularly in cases of severe tigecycline-associated thrombocytopenia, and undertake routine monitoring of patients' platelet counts, especially for those who possess three or more risk factors.

Immune Thrombocytopenia: A Rare Adverse Event of Vancomycin Therapy

Vancomycin, a glycopeptide antibiotic, is widely used for Gram-positive cocci or bacilli bacteria-induced serious infections. Although considered safe and effective, it still causes adverse events. Vancomycin-induced immune thrombocytopenia is a rarely reported adverse event, manifesting from asymptomatic thrombocytopenia to life-threatening bleeding. We underline a case of a 56-year-old male with a diabetic foot with an infected exudating purulent ulcer. He experienced a significant drop in platelet count after commencing vancomycin, and discontinuing vancomycin resulted in improved platelet count with positive vancomycin-induced anti-platelet antibodies. After ruling out other possible causes of thrombocytopenia, a presumptive diagnosis of vancomycin-induced thrombocytopenia was made.

Severe Late-Onset Drug-Induced Immune Thrombocytopenia Following IFN β-1a Treatment: A Case Report of a 52-Year-Old Woman with Relapse-Remitting Multiple Sclerosis

Interferon β-1a (IFNβ1a) is considered safe in relapsing-remitting multiple sclerosis (RRMS). Drug-induced thrombocytopenia (DITP) is a rare but underreported adverse event that is often confused with other causes of thrombocytopenia. We report the case of a 52-year-old woman who developed limb and oral mucosa petechiae and hematochezia, 10 years after beginning IFNβ1a. Blood work showed an isolated severe thrombocytopenia and ruled out other autoimmune diseases, viral infections, intravascular hemolysis, and renal impairment. Oral corticosteroids and tranexamic acid were initiated with a favorable platelet response. IFNβ1a was resumed, leading to recurrence of thrombocytopenia. Platelets came back to normal after intravenous immunoglobulins and IFNβ1a was definitively discontinued. To our knowledge, this is the first case of drug-induced immune thrombocytopenia (DITP) associated with IFNβ1a.

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.

Acute drug-induced immune thrombocytopenia - A work of articaine

Background

Drug‐induced immune thrombocytopenia (DITP) is a rare, but serious complication to a wide range of medications. Upon suspicion, one should do a thorough clinical evaluation following proposed diagnostic criteria and seek laboratory confirmation. If confirmed, it is important to ensure avoidance of the drug in the future.

Study design and methods

Herein, we describe a young adult male who experienced two bouts of severe thrombocytopenia following dental treatment. The thrombocytopenia was acknowledged due to unexpected hemorrhaging during the procedures. On both occasions, he was exposed to four different drugs, none commonly associated with DITP. After the second episode of severe procedural‐related thrombocytopenia, an investigation into the cause was initiated. We describe the clinical approach to elucidate which of the four implicated drugs was responsible for thrombocytopenia and the laboratory work‐up done to confirm that the reaction was antibody‐mediated and identify the antibody's drug: glycoprotein specificity. An alternative drug was tested both in vivo and in vitro, to identify an option for future procedures.

Results

Sequential exposure revealed the local anesthetic substance articaine to induce thrombocytopenia. Laboratory work‐up confirmed drug‐dependent antibodies (DDAbs) with specificity for the glycoprotein Ib/IX complex, swiftly identified by a bead‐based Luminex assay. Further investigations by monoclonal antibody immobilization of platelet antigens assay (MAIPA) revealed a probable GPIb binding site. An alternative local anesthetic, lidocaine, was deemed safe for future procedures.

Conclusion

Articaine can induce rapid‐onset, severe immune‐mediated thrombocytopenia causing bleeding complications. A modified bead‐based Luminex platelet antigen assay proved a useful addition in the DITP‐investigation.

A severe oxaliplatin immune-induced syndrome after oxaliplatin-based pressurized intraperitoneal aerosol chemotherapy (PIPAC)

Objectives

Oxaliplatin immune-induced syndrome (OIIS) was recently recognized as an uncommon complication of oxaliplatin therapy.

Methods

We report an exceptionally OIIS after pressurized intraperitoneal aerosol chemotherapy (PIPAC).

Results

Our patient developed a severe OIIS probably related to the intraperitoneal administration of oxaliplatin. Specific tests were performed and detected high-titer antibodies to oxaliplatin.

Conclusions

The OIIS is a rare. Physicians had to be aware of that clinical situation because it could be reversible, even in case of peritoneal advanced disease, and ICU treatment is justified.

Evaluation of the Expression Profile of Antibiotic-Induced Thrombocytopenia Using the Japanese Adverse Drug Event Report Database

Drug-induced thrombocytopenia (DITP) can be triggered by antibiotics; however, the details remain unclear. Here, we evaluated the expression profiles of DITP using the Japanese Adverse Drug Event Report (JADER) database. We analyzed reports of DITP between April 2004 and January 2021 from the JADER database. The reporting odds ratio (ROR) and 95% confidence interval (CI) were used to detect DITP signals. Factors thought to affect DITP, such as male sex and an age of at least 60 years, were added as covariates. We evaluated the time-to-onset profile and hazard type using the Weibull shape parameter. The JADER database contained 1,048,576 reports. Twelve of 60 antibiotics showed signals for DITP; the RORs (95% CIs) for ampicillin/sulbactam, ceftazidime, cefozopran, ciprofloxacin, fluconazole, fos-fluconazole, linezolid, pazufloxacin, piperacillin/tazobactam, teicoplanin, trimethoprim/sulfamethoxazole, and voriconazole were 1.75 (1.41-2.16), 1.77 (1.42-2.18), 1.35 (1.06-1.72), 2.56 (2.19-2.98), 1.93 (1.67-2.23), 2.08 (1.76-2.46), 5.29 (2.73-9.60), 1.92 (1.51-2.41), 1.54 (1.05-2.19), 1.47 (1.16-1.84), 1.92 (1.73-2.14), and 2.32 (1.59-3.30), respectively. In multiple logistic regression analysis, 7 and 6 antibiotics were detected for the factors age and male sex, respectively. The median times-to-onset of DITP for ciprofloxacin (oral treatment), fluconazole, linezolid, piperacillin/tazobactam, and trimethoprim/sulfamethoxazole were 91, 91, 11.5, 10, and 9 days, respectively. Furthermore, the 95% CI of the Weibull shape parameter β for these antibiotics was above and excluded 1, indicating that the antibiotics were the wear out failure type. We revealed the expression profiles of DITP following treatment with 12 antibiotics.

Rare complication of ceftriaxone therapy: drug-induced thrombocytopenia (DITP)

A 62-year-old woman with a history of end-stage renal disease on haemodialysis, essential hypertension and type 2 diabetes mellitus was diagnosed with sepsis and placed on 600 mg oral linezolid every 12 hours and 1 g intravenous ceftriaxone every 24 hours. Blood cultures grew Streptococcus dysgalactiae, and she was switched to intravenous ceftriaxone 2 g daily. Platelet counts slowly trended down after starting ceftriaxone reaching 5 K/μL on day 12 of treatment. Ceftriaxone was discontinued and heparin-induced thrombocytopaenia was ruled out. She was switched to vancomycin and her platelet count improved. Given the temporal relationship between changing platelet counts and starting and discontinuing ceftriaxone, a diagnosis of drug-induced thrombocytopaenia was made.

Roxithromycin-Associated Acute Thrombocytopenia

Patient: Female, 78-year-old

Final Diagnosis: Acute autoimmune thrombocytopenia

Symptoms: Petechial lesions of the palate • two hematomas of the tongue and purpuric macules with central crust in the abdomen and in the left lower limb

Medication: —

Clinical Procedure: —

Specialty: Hematology • Pharmacology and Pharmacy

Adalimumab-Induced Thrombocytopenia in a Patient With Hidradenitis Suppurativa

Adalimumab-induced thrombocytopenia is a rarely occurring condition that may present with hemorrhagic manifestations. This report describes a case of a patient who presented with severe, symptomatic thrombocytopenia while on adalimumab for the treatment of hidradenitis suppurativa. The patient responded to treatment with steroids, intravenous immunoglobulin (IVIG), and platelet transfusion, in addition to discontinuation of adalimumab.

Rifampicin-Induced Thrombocytopenia: A Case Report and Short Review of the Literature

Thrombocytopenia may be associated with a variety of conditions and risks depending on its severity, ranging from mild epistaxis to life-threating bleeding. Many drugs or herbal remedies can cause thrombocytopenia by either inhibiting platelet production and/or enhancing their destruction from the peripheral blood mediated via an immunological mechanism implicating drug-dependent antibodies. The latter entity is called drug-induced immune thrombocytopenia: a life-threatening, under-recognised condition, which is often a diagnostic challenge. Rifampicin is a widely used, well-tolerated, and effective bactericidal drug. Adverse events, except for gastrointestinal effects, headache, skin rash, and pruritus, are uncommon. The authors herein report on a patient with isolated thrombocytopenia with a recent medical history of brucellosis on rifampicin and doxycycline. Thrombocytopenia was proved to be rifampicin-induced. Also presented is a short review of the literature on this rare subject, which should be of great importance to clinicians.

Panitumumab-Associated Drug-Induced Immune Thrombocytopenia in a Patient with Colorectal Cancer

Severe thrombocytopenia is a rare adverse event of panitumumab. Here, we report the first patient with metastatic colorectal cancer who developed severe thrombocytopenia, diagnosed as panitumumab-associated drug-induced immune thrombocytopenia (DITP). A clinical diagnosis of DITP can be obtained by excluding other causes of thrombocytopenia and is confirmed by the recovery of thrombocytopenia after the discontinuation of the suspected drug. Treatment includes permanent discontinuation of the suspected drug. Re-exposure should be avoided. It should be kept in mind that panitumumab can induce DITP in the case of a new, sudden, unexpected, and isolated drop in platelet count after excluding other causes of thrombocytopenia.

Vancomycin-induced thrombocytopenia in endocarditis: A case report and review of literature

BACKGROUND

Thrombocytopenia is a serious complication in the medical practice of numerous drugs. Vancomycin is frequently used for the prophylaxis and treatment of suspected or identified methicillin-resistant positive infections. Several cases with vancomycin-induced thrombocytopenia (VIT) have been reported. However, these have rarely been extensively reviewed. The present report describes a case of VIT in endocarditis, and reviews all VIT cases reported in the literature.

CASE SUMMARY

A 26-year-old male diagnosed with infective endocarditis was admitted. The patient was treated with multiple drugs, including vancomycin, which was initially intravenously given at 1000 mg every 12 h and subsequently at 500 mg every 8 h on day 3. On day 11, the platelet count decreased to 51 × 10⁹/L, vancomycin was switched to 500 mg every 12 h, and platelet transfusion was given. On day 17, the platelet count dropped to 27 × 10⁹/L, and platelet transfusion was administered again. On day 23, vancomycin was adjusted to 500 mg every 8 h as the trough concentration dropped to the minimum effective concentration. On day 33, the platelet count declined to approximately 40 × 10⁹/L. After platelet transfusion, the platelet count rebounded to 90 × 10⁹/L on day 35 but dropped again to 42 × 10⁹/L on day 43. Based on the time-to-platelet count curve and Naranjo’s Adverse Drug Reaction Probability Scale score, VIT was suspected. After vancomycin discontinuation and platelet transfusion, the platelet count gradually normalized.

CONCLUSION

The diagnosis of VIT can be achieved through the time-to-platelet count curve and Naranjo’s Adverse Drug Reaction Probability Scale score. The platelet count cannot be normalized simply by platelet transfusion alone, and vancomycin discontinuation is essential.

Acyclovir-induced immune thrombocytopenia: Case report and review of the literature

There are a number of medications which can serve as catalysts for drug-induced immune thrombocytopenia (DIPT). A minimum of six different mechanisms have been put forward as the means by which drug-induced antibodies can encourage platelet destruction, thus emphasising the complexity of the pathogenesis of DITP. Acyclovir, has been widely used because of its highly potent prohibitive properties for infections caused by HSV and VZV. The common adverse effects of this drug are well known, the severe adverse reactions are mostly related to high dose intravenous administrations. The immune thrombocytopenia induced by acyclovir is unusual. The authors present a rare clinical case of acyclovir-induced immune thrombocytopenia in a 72-year-old female patient with typical herpes zoster treated with acyclovir. The clinical and laboratory findings, taken together with the transitory relationship between acycolvir and the start of thrombocytopenia, combined with the elimination of the other know sources of thrombocytopenia, allowed us to reach the diagnosis of acyclovir-induced immune thrombocytopenia. An international database search was employed to complete an extensive review of the current literature. Contemporary information on acyclovir-induced immune thrombocytopenia was collected by the analysis of present day review articles and accessible case reports. The authors found five published cases of acyclovir-induced immune thrombocytopenia. Analyzing these articles it was concluded that immune thrombocytopenia induced by acyclovir is rare, and an unusual side effect, with good prognosis. Prompt diagnosis is vital to appropriate management, therefore clinicians need to be cognisant of this rare potential adverse reaction.

A Case of Vancomycin-Induced Immune Thrombocytopenia

Vancomycin-induced immune thrombocytopenia (ITP) is a rare, potentially life-threatening complication from an antibiotic frequently used in medical practice. We report a case of an 81-year-old male with recent removal of an infected right knee prosthesis and insertion of an articulating antibiotic spacer, presenting from rehabilitation for severe thrombocytopenia (1 X 10³/µL). The patient’s thrombocytopenia was initially falsely attributed to rifampin-induced ITP, a much more common cause of drug-induced thrombocytopenia. Only later, after a second precipitous drop in platelet count, vancomycin was correctly identified as the culprit. The patient’s serum was tested for drug-dependent platelet antibodies with and without vancomycin. A positive reaction for IgG was detected by flow cytometry in the absence of vancomycin, which was potentiated in the presence of vancomycin. The result indicated the presence of vancomycin-dependent and nondrug-dependent platelet reactive antibodies and confirmed the diagnosis of vancomycin-induced ITP. In this case, the correct diagnosis was masked by the simultaneous administration of two drugs that cause drug-induced ITP and highlights the importance of early recognition of rare, vancomycin-induced ITP.

Acute thrombocytopenia after anticoagulation with rivaroxaban: A case report

BACKGROUND

Novel oral anticoagulants (NOACs) are commonly used for the anticoagulation of patients with atrial fibrillation. Reports of thrombocytopenic toxicity of NOACs are limited. In this report, we present a case of thrombocytopenia likely induced by rivaroxaban, which is an extremely rare adverse drug reaction.

CASE SUMMARY

A 70-year-old man presented to the cardiovascular department with a chief complaint of intermittent chest tightness and dyspnea over the last five years. Vital signs were within normal limits at presentation, with a heart rate of 65 beats/min, blood pressure of 138/78 mmHg, respiratory rate of 19 breaths/min, and temperature of 36.1°C. Laboratory tests indicated a platelet count of 163 × 10⁹/L on admission. Anticoagulant therapy with rivaroxaban, a NOAC, was started on the second day of hospitalization. The platelet count decreased to 30 × 10⁹/L on hospital day 11 and then 10 × 10⁹/L on day 12. Rivaroxaban was stopped on day 13 when the platelet count decreased to 5 × 10⁹/L. After the cessation of rivaroxaban, the platelet count returned to normal. The patient was diagnosed with thrombocytopenia, which was likely induced by rivaroxaban. The incidence of thrombocytopenic toxicity of NOACs is extremely low.

CONCLUSION

Thrombocytopenia during anticoagulation therapy may be associated with a high risk of life-threatening bleeding. For elderly patients, changes in platelet count should be carefully monitored at the beginning of NOAC treatment, and we should be on the alert for bleeding events as well.

Thrombocytopenia Caused by Dexamethasone in a Patient with Colorectal Cancer

Drug-induced immune thrombocytopenia (DITP) is an important cause of thrombocytopenia. A 73-year-old man with relapsed rectal carcinoma received S-1, oxaliplatin and bevacizumab combination therapy (SOX+Bev). Dexamethasone was administered as an antiemetic prophylaxis. On day 2 of the first cycle, thrombocytopenia (8,000/μL) was observed. We sequentially omitted any drugs suspected to possibly induce thrombocytopenia and confirmed dexamethasone as the cause of thrombocytopenia. DITP induced by synthetic corticosteroids is very rare and this is the first case report of DITP induced by dexamethasone. Although rare, DITP due to synthetic corticosteroids including dexamethasone should be a differential diagnosis among patients receiving synthetic corticosteroids with thrombocytopenia.

A Case of Confirmed Ceftriaxone-induced Immune Thrombocytopenia

Drug-induced immune thrombocytopenia (DITP) is a rare, but potentially fatal cause of isolated thrombocytopenia. DITP is thought to occur when drug-dependent antibodies bind to the platelet membrane glycoproteins to activate platelet consumption signaling. Common implicated drugs include quinine/quinidine, penicillamines, valproic acid and cotrimoxazole. Ceftriaxone is a rare culprit with only six reported cases since 1991, of which only three were confirmed with drug-dependent antiplatelet antibodies. We describe a case of antibody confirmed ceftriaxone-induced immune thrombocytopenia after initiation of empiric antibiotic therapy for acute bacterial meningitis.

Metronidazole caused profound drug-induced immune thrombocytopenia

Metronidazole is commonly prescribed and has not been known to cause drug‐induced immune thrombocytopenia. We have provided clinical and laboratory evidence with DDabs that metronidazole can cause drug‐induced immune thrombocytopenia (DITP). Providers must be aware of metronidazole causing DITP because recognition of thrombocytopenia is critical and cessation of the drug should occur promptly.

Vancomycin-Induced Thrombocytopenia: A Narrative Review

Thrombocytopenia has been reported as an adverse reaction of numerous drugs. Vancomycin is often overlooked as a culprit but has been associated with several cases of thrombocytopenia that were not well described in the literature. A literature search was conducted to find reports of thrombocytopenia induced by vancomycin. Biomedical databases including 'PubMed', 'Scopus', and 'Web of Science' were searched using terms 'vancomycin', 'platelet', 'pancytopenia', 'thrombocytopenia', and 'bleeding'. English language articles published before July 2015 were included. Thirty-nine papers including 29 case reports (30 cases), five observational studies, two clinical trials, two letters, and one case series remained for final analysis. The main route of administration was intravenous infusion. This adverse reaction seems to be duration dependent with the mean time to platelet nadir count of 8 days in reported cases. The interval may be significantly shorter in re-exposure to the drug. Platelet nadir counts ranged from 2000 to 100,000/mL in patients who experienced bleeding. Vancomycin-specific antibodies were detected in 13 of 17 patients who were tested in the case reports. Based on the Naranjo Adverse Drug Reaction Probability Scale, reaction was 'definite', 'probable', and 'possible' in 1, 15, and 14 patients, respectively. Among 30 cases, vancomycin was discontinued in 29 patients and platelets returned to normal counts within 5-6 days in 17 of them; in one patient, vancomycin was not discontinued, but platelet count recovered 11 days after the nadir time. Transfusion might be recommended if severe thrombocytopenia and bleeding occurs. Intravenous immunoglobulins, corticosteroids, rituximab, and plasma exchange should be reserved for patients with resistant thrombocytopenia and severe bleeding as mentioned in a number of reports.

Comparative Analysis of the Suspected Heparin-Induced Thrombocytopenia Level in Korea

The primary objective of our study was to evaluate the frequency of suspected heparin-induced thrombocytopenia (HIT) among patients treated with different formulations of heparin and investigate the factors that affect the incidence of HIT. This study is an electronic medical record (EMR)-based large-scale retrospective cohort study conducted from 2009 to 2014 in Korea. After hospitalization, patient platelet count was determined before heparin was prescribed, and all platelet count values obtained during hospitalization were extracted. Suspected HIT was estimated by three 4Ts scores (acute thrombocytopenia, timing onset and other possible causes), which when combined yielded a high probability of HIT. Among 6046 patients enrolled in this study, HIT was suspected in 641 cases (10.6%) and a statistically significant increase in HIT incidence rate was observed for three heparins used (p < 0.001). Dalteparin (HR = 0.55, p = 0.036) and enoxaparin (HR = 0.40, p < 0.001) showed a relatively low HIT incidence rate, compared to unfractionated heparin. Majority of suspected HIT cases (76.9 and 66.7%) occurred in days 8-10 and 5-7 of dalteparin and enoxaparin treatments, respectively. Most of the patients medicated with dalteparin were cancer patients; however, no statistically significant relationship was observed between HIT occurrence and cancer. HIT can cause serious complications, making early diagnosis crucial. Clinical practitioners first prescribing heparin should focus on preventing and detecting complications early by conducting frequent, regular platelet counts before and after heparin administration.

Ciprofloxacin-induced immune-mediated thrombocytopenia: No cross-reactivity with gemifloxacin

WHAT IS KNOWN AND OBJECTIVE

Fluoroquinolone-induced immune-mediated thrombocytopenia is uncommon, and no reports of cross-reactivity among fluoroquinolones exist. Here, we describe a case of ciprofloxacin-induced immune thrombocytopenia with no cross-reactivity with gemifloxacin.

CASE DESCRIPTION

A 77-year-old woman showed profound thrombocytopenia immediately after two ciprofloxacin injections for pneumonia. Platelet counts recovered rapidly after ciprofloxacin discontinuation. She had experienced thrombocytopenia after ciprofloxacin administration 4 years earlier, which was assumed to be ciprofloxacin-induced immune-related. Interestingly, no thrombocytopenia occurred following the subsequent exposure to another fluoroquinolone, gemifloxacin.

WHAT IS NEW AND CONCLUSION

No cross-reactivity occurred between ciprofloxacin and gemifloxacin in this fluoroquinolone-induced immune thrombocytopenia case.

Cytopenias among ART-naive patients with advanced HIV disease on enrolment to care and treatment services at a tertiary hospital in Tanzania: A cross-sectional study

BACKGROUND

HIV/AIDS causes high morbidity and mortality through both immunosuppression and complications not directly related to immunosuppression. Haematological abnormalities, including various cytopenias, occur commonly in HIV through immune and non-immune pathways. Though these complications could potentially cause serious clinical implications, published literature on the magnitude of this problem and its associated factors in Tanzania is scarce. This study aimed at determining the prevalence and risk factors of HIV-associated cytopenias among ART-naive patients enrolling for care and treatment services at Bugando Care and Treatment Centre (CTC) in Mwanza, Tanzania.

METHODS

This was a cross-sectional clinic-based study done between March 2015 and February 2016, involving all antiretroviral therapy (ART)-naive adult HIV-positive patients enrolling for care and treatment services at Bugando CTC. Patients younger than 18 years and those with missing data were excluded. Data were analysed using Stata version 11 to determine the prevalence and risk factors of cytopenias.

RESULTS

A total of 1205 ART-naive patients were included. Median age was 41 years (interquartile range [IQR] 32 to 48). Most participants were female (n = 789; 65.6%), with a female-to-male ratio of 2:1. The median baseline CD4 count was 200 cells/µL (IQR 113 to 439). About half (49%) of the study participants had baseline CD4 counts less than 200 cells/µL. Anaemia, leucopenia, and thrombocytopenia were found in 704 (58.4%), 285 (23.6%), and 174 (14.4%) participants, respectively, and these were strongly associated with advanced HIV infection.

CONCLUSIONS

The magnitude of cytopenias is high among ART-naive HIV-positive adults, and cytopenias are more marked with advanced HIV infection. Early diagnosis of HIV and timely initiation of ART could potentially reduce the number of people living with advanced HIV disease and its associated complications, including the cytopenias investigated in this study. Patients with cytopenias should undergo thorough screening for tuberculosis, which is an important and treatable correlate of cytopenia, in addition to close follow-up for any potential negative outcomes.

Vancomycin-induced thrombocytopenia: a rare adverse effect in a patient -submitted to bone graft in the jaw

INTRODUCTION

Thrombocytopenia is the reduction in the number of blood -platelets, which may be caused by -several different conditions such as sepsis, disseminated intravascular -clotting, and large blood losses. Additionally, in rare situations, thrombocytopenia may also be induced by the use of medicaments. One of these drugs is the vancomycin, a glycopeptide presently used against -serious infections involving Gram-positive bacteria such as the methicillin-resistant Staphylococcus aureus and penicillin-resistant Streptococcus.

OBJECTIVE

The objective of this study is to report on a case of serious vancomycin-induced thrombocytopenia in a patient infected with methicillin-resistant S. aureus after mandibular reconstruction with autogenous bone graft, and to draw attention to the importance of this clinically rare adverse effect.

CONCLUSION

Vancomycin-induced thrombocytopenia is a rare condition, which is also a significant disorder that demands attention and the rapid identification and replacement of the antimicrobial agent.

Structural basis for quinine-dependent antibody binding to platelet integrin αIIbβ3

Drug-induced immune thrombocytopenia (DITP) is caused by antibodies that react with specific platelet-membrane glycoproteins when the provoking drug is present. More than 100 drugs have been implicated as triggers for this condition, quinine being one of the most common. The cause of DITP in most cases appears to be a drug-induced antibody that binds to a platelet membrane glycoprotein only when the drug is present. How a soluble drug promotes binding of an otherwise nonreactive immunoglobulin to its target, leading to platelet destruction, is uncertain, in part because of the difficulties of working with polyclonal human antibodies usually available only in small quantities. Recently, quinine-dependent murine monoclonal antibodies were developed that recognize a defined epitope on the β-propeller domain of the platelet integrin αIIb subunit (GPIIb) only when the drug is present and closely mimic the behavior of antibodies found in human patients with quinine-induced thrombocytopenia in vitro and in vivo. Here, we demonstrate specific, high-affinity binding of quinine to the complementarity-determining regions (CDRs) of these antibodies and define in crystal structures the changes induced in the CDR by this interaction. Because no detectable binding of quinine to the target integrin could be demonstrated in previous studies, the findings indicate that a hybrid paratope consisting of quinine and reconfigured antibody CDR plays a critical role in recognition of its target epitope by an antibody and suggest that, in this type of drug-induced immunologic injury, the primary reaction involves binding of the drug to antibody CDRs, causing it to acquire specificity for a site on a platelet integrin.

Drug-Induced Thrombocytopenia following a Transvaginal Oocyte Retrieval for In Vitro Fertilization

Drug-induced immune thrombocytopenia has been associated with hundreds of medications and can lead to devastating consequences for the patient. We present a case of a healthy 33-year-old female undergoing in vitro fertilization who developed a severe drug-induced thrombocytopenia, petechiae, and a large hemoperitoneum after receiving Cefazolin antibiotic prophylaxis for a transvaginal oocyte retrieval. The patient was admitted to the intensive care unit for resuscitation with blood products. The presence of drug-dependent platelet antibodies to Cefazolin was confirmed serologically.

Fatal quinine-induced thrombocytopenia from pulmonary haemorrhage

Severe drug-induced thrombocytopenia is a well known but rare complication of quinine. This paper presents a discussion on quinine-induced thrombocytopenia based on a patient who developed fatal thrombocytopenia and pulmonary haemorrhage.

Potential mechanisms for thrombocytopenia development with trastuzumab emtansine (T-DM1)

PURPOSE

Trastuzumab-emtansine (T-DM1) is an antibody-drug conjugate (ADC) comprising the cytotoxic agent DM1 conjugated to trastuzumab with a stable linker. Thrombocytopenia was the dose-limiting toxicity in the phase I study, and grade ≥3 thrombocytopenia occurred in up to 13% of patients receiving T-DM1 in phase III studies. We investigated the mechanism of T-DM1-induced thrombocytopenia.

EXPERIMENTAL DESIGN

The effect of T-DM1 on platelet function was measured by aggregometry, and by flow cytometry to detect the markers of activation. The effect of T-DM1 on differentiation and maturation of megakaryocytes (MK) from human hematopoietic stem cells was assessed by flow cytometry and microscopy. Binding, uptake, and catabolism of T-DM1 in MKs, were assessed by various techniques including fluorescence microscopy, scintigraphy to detect T-[H(3)]-DM1 and (125)I-T-DM1, and mass spectrometry. The role of FcγRIIa was assessed using blocking antibodies and mutant constructs of trastuzumab that do not bind FcγR.

RESULTS

T-DM1 had no direct effect on platelet activation and aggregation, but it did markedly inhibit MK differentiation via a cytotoxic effect. Inhibition occurred with DM1-containing ADCs but not with trastuzumab demonstrating a role for DM1. MKs internalized these ADCs in a HER2-independent, FcγRIIa-dependent manner, resulting in intracellular release of DM1. Binding and internalization of T-DM1 diminished as MKs matured; however, prolonged exposure of mature MKs to T-DM1 resulted in a disrupted cytoskeletal structure.

CONCLUSIONS

These data support the hypothesis that T-DM1-induced thrombocytopenia is mediated in large part by DM1-induced impairment of MK differentiation, with a less pronounced effect on mature MKs.

Amoxicillin/Clavulanic Acid-induced thrombocytopenia

INTRODUCTION AND OBJECTIVE

Drug-induced thrombocytopenia is a common adverse effect reported in the literature. Typically patients present with a low platelet count with signs and symptoms ranging from bruising to bleeding, and major organ damage. Penicillin-induced thrombocytopenia previously reported in the literature is explained primarily through the hapten-dependent antibody process. The goal of this report is to present a case of an amoxicillin/clavulanic acid-induced thrombocytopenia.

CASE PRESENTATION

A 23-year-old male presented to the emergency department with bruises on his arms and legs after completing a full course of amoxicillin/clavulanic acid of 625 mg twice a day for 5 days for tonsillitis. After several tests, the patient was diagnosed with thrombocytopenia induced by amoxicillin/clavulanic acid. The patient was treated with a corticosteroids taper regimen for 3 weeks. He was discharged after 3 days of inpatient treatment with instructions to avoid physical activity for 2 weeks. Two weeks post discharge, the follow-up showed that the platelet count had increased.

DISCUSSION

Penicillin-induced thrombocytopenia has been previously reported in the inpatient setting where bleeding was observed. However, the patient in this case report presented with bruises on his arms and legs. The diagnosis was made by the process of elimination; not all possible tests were conducted. The patient was prescribed corticosteroids that are not indicated for drug-induced thrombocytopenia. The Naranjo scale showed that this is a probable adverse event of amoxicillin/clavulanic acid.

CONCLUSION

This is a unique case where amoxicillin/clavulanic acid was reported to be a probable cause of thrombocytopenia in an outpatient setting without signs of bleeding and without concomitant medications.

Bendamustine-induced immune hemolytic anemia in a chronic lymphocytic leukemia patient: A case report and review of the literature

Bendamustine is an alkylating agent approved for the treatment of chronic lymphocytic leukemia (CLL) and B-cell non-Hodgkin lymphoma. There are scant reports on bendamustine-induced immune hemolytic anemia occurring mainly in CLL patients. We report a case of immune hemolytic anemia that developed after exposure to bendamustine in a 70-year-old female with CLL who was previously exposed to fludarabine. Previous exposure to fludarabine is a common finding in the majority of reported cases of bendamustine drug-induced immune hemolytic anemia (DIIHA), including our case. Bendamustine should be suspected as the cause of any hemolytic anemia that develops while on this drug, especially in CLL patients treated previously with fludarabine.

Drug-Induced Thrombocytopenia in the Critically Ill

Background:Drugs are suspected when obvious causes of intensive care unit (ICU)-acquired thrombocytopenia have been excluded. It has been estimated that 10% to 25% of cases may be drug induced. Objectives: The objectives of this study were to evaluate the risk of thrombocytopenia associated with drug classes commonly used in the ICU. Methods: Data concerning patients admitted for more than 48 hours between 1997 and 2011 were extracted from a research-purpose database. Patients with thrombocytopenia within the first 72 hours of admission and with diagnoses or interventions considered strongly associated with thrombocytopenia were excluded. Drug exposures were compared and adjusted for confounders using conditional logistic regression. Results: A total of 238 cases were identified after exclusions. Each case was matched according to sex, age, admission year, and admission unit with 1 control. In univariate analysis, quinolones (odds ratio [OR] = 1.56; 95% CI = 1.01-2.40) and extended spectrum β-lactams (OR = 1.71; 95% CI = 1.00-2.93) were significantly associated with an increased risk of thrombocytopenia. After adjusting for confounders, exposure to quinolones was the only drug class with a statistically significant increase in risk of thrombocytopenia (OR = 1.697; 95% CI = 1.002-2.873; P = 0.049). Conclusion: In this study of ICU-acquired thrombocytopenia, we found no association between the exposures to several antibiotic classes, anticonvulsants, antiplatelet agents, nonsteroidal anti-inflammatory agents, and heparins and thrombocytopenia. As linezolid was not studied, no conclusions can be drawn concerning this agent. The statistically significant association between quinolones and thrombocytopenia warrants further investigation.

Drug-induced immune thrombocytopenia: incidence, clinical features, laboratory testing, and pathogenic mechanisms

Drug-induced immune thrombocytopenia (DIIT) is a relatively uncommon adverse reaction caused by drug-dependent antibodies (DDAbs) that react with platelet membrane glycoproteins only when the implicated drug is present. Although more than 100 drugs have been associated with causing DIIT, recent reviews of available data show that carbamazepine, eptifibatide, ibuprofen, quinidine, quinine, oxaliplatin, rifampin, sulfamethoxazole, trimethoprim, and vancomycin are probably the most frequently implicated. Patients with DIIT typically present with petechiae, bruising, and epistaxis caused by an acute, severe drop in platelet count (often to <20,000 platelets/pL). Diagnosis of DIIT is complicated by its similarity to other non-drug-induced immune thrombocytopenias, including autoimmune thrombocytopenia, posttransfusion purpura, and platelet transfusion refractoriness, and must be differentiated by temporal association of exposure to a candidate drug with an acute, severe drop in platelet count. Treatment consists of immediate withdrawal of the implicated drug. Criteria for strong evidence of DIIT include (1) exposure to candidate drug-preceded thrombocytopenia; (2) sustained normal platelet levels after discontinuing candidate drug; (3) candidate drug was only drug used before onset of thrombocytopenia or other drugs were continued or reintroduced after resolution of thrombocytopenia, and other causes for thrombocytopenia were excluded; and (4) reexposure to the candidate drug resulted in recurrent thrombocytopenia. Flow cytometry testing for DDAbs can be useful in confirmation of a clinical diagnosis, and monoclonal antibody enzyme-linked immunosorbent assay testing can be used to determine the platelet glycoprotein target(s), usually GPIIb/IIIa or GPIb/IX/V, but testing is not widely available. Several pathogenic mechanisms for DIIT have been proposed, including hapten, autoantibody, neoepitope, drug-specific, and quinine-type drug mechanisms. A recent proposal suggests weakly reactive platelet autoantibodies that develop greatly increased affinity for platelet glycoprotein epitopes through bridging interactions facilitated by the drug is a possible mechanism for the formation and reactivity of quinine- type drug antibodies.

Meloxicam-induced thrombocytopenia

Immune thrombocytopenia can have several causes including the use of certain drugs. Thrombocytopenia has been documented as a rare adverse effect of some nonsteroidal antiinflammatory drugs (NSAIDs) including diclofenac, naproxen, and ibuprofen. However, only one previously documented case of meloxicam-associated thrombocytopenia has been reported in the literature. We describe an 84-year-old woman who developed a case of immune-mediated thrombocytopenia that was attributed to meloxicam therapy. The patient's platelet count decreased from a baseline of 267 × 10(3) /mm(3) to 2 × 10(3) /mm(3) 1 week after she received her first lifetime dose of meloxicam. She also experienced black stools and bruising that coincided with the meloxicam administration. The almost immediate onset of thrombocytopenia and symptoms after initiation of meloxicam, as well as the marked reduction in her platelet count, suggest an idiosyncratic reaction. According to the Hill criteria for assessing causality of adverse drug events, it is plausible that this reaction was due to meloxicam. Health care providers should be aware of the possibility of thrombocytopenia secondary to NSAID therapy including meloxicam. Immune thrombocytopenia can be life threatening if it is not identified and treated promptly. A thorough medication history is particularly important when patients present with unusual symptoms, with a focus on those drugs that have been recently initiated. Although thrombocytopenia is a rare adverse effect of NSAID therapy, it should be considered a potential cause in patients receiving these drugs who have signs and symptoms consistent with this blood dyscrasia.

A 7-year case of furosemide-induced immune thrombocytopenia

Immune thrombocytopenia has been attributed to many causes. Several drugs have been implicated as culprits in causing drug-induced thrombocytopenia. Although the mechanism for this type of thrombocytopenia is not well understood, at least three types of antibodies appear to be involved: drug-dependent antibodies, hapten-dependent antibodies, and drug-induced platelet-reactive autoantibodies. In this report, we describe a case in which furosemide was identified as the probable cause of drug-induced thrombocytopenia in an 84-year-old man with chronic symptomatic idiopathic thrombocytopenia for seven years before discovery. The patient's platelet count and daily furosemide dose, both intravenous and oral, were documented throughout his medical history. A dose-dependent change in platelet count was observed in association with the furosemide dose. His platelet count increased on discontinuation of furosemide and beginning of torsemide. Several months after discontinuation of furosemide, his platelet count increased to a 9-year high of 206 × 10³/mm³ from a low of 36 × 10³/mm³ while receiving furosemide therapy. Based on the observations of this case report, clinicians should more readily consider furosemide as a potential cause of thrombocytopenia.

Rifabutin-Induced Thrombocytopenia from Concurrent Use of High-Dose Fluconazole

Objective:

To report a case of—and review the literature supporting—rifabutin-induced thrombocytopenia from concurrent use of high-dose fluconazole.

Case Summary:

A 34-year-old man with AIDS, on a stable regimen that included rifabutin and fluconazole for the previous 3 months, was admitted to the hospital with symptoms of oropharyngeal candidiasis. He was treated with increased doses of fluconazole 200 mg to 800 mg daily over a 9-day hospital admission. During this time, his platelet count decreased from 441,000 cells/mm3 to 24,000 cells/mm3, with no signs of bleeding. He was discharged on day 9 and instructed to omit 1 dose of rifabutin and continue fluconazole 200 mg daily. On day 12, his platelet count was 118,000 cells/mm3. About 1 month after discharge, his platelet count was 151,000 cells/mm3.

Discussion:

Rifabutin is known to cause thrombocytopenia. Results from initial studies evaluating various doses of rifabutin were not conclusive as to whether rifabutin-induced thrombocytopenia is a dose-dependent effect. With increased use of rifabutin, often in combination with potentially interacting medications, reports of thrombocytopenia have gained frequency. One study showed that patients on higher doses of rifabutin experienced thrombocytopenia significantly more often than did those on lower doses. When rifabutin is administered with fluconazole, there is a clear pharmacokinetic interaction, showing a 76–82% increase in the rifabutin area under the concentration curve, with only uveitis and leukopenia reported. An objective causality assessment of this case classified the interaction between fluconazole and rifabutin, resulting in thrombocytopenia, as probable. Other causes of thrombocytopenia in our patient, including AIDS, Mycobacterium avium complex, fluconazole, famotidine, and ritonavir, are less likely.

Conclusions:

We describe the first case of rifabutin-induced thrombocytopenia from concurrent use of high-dose fluconazole. There is evidence to support this interaction and practitioners should be aware of this potential adverse effect.