Identifying drugs that cause acute thrombocytopenia: an analysis using 3 distinct methods

Differentiation of antimicrobial toxicity and sepsis-induced disseminated intravascular coagulation in an orthopedic burn patient in India: a case report

Drug-induced thrombocytopenia, hemolytic anemia, and leukopenia are serious, and sometimes fatal, complications of common medications. These conditions are challenging to diagnose in patients with polytrauma injuries due to the presence of multiple potential etiologies. In such clinical scenarios, sepsis-induced disseminated intravascular coagulation is a more frequent diagnosis. The clinical manifestations of these conditions can be indistinguishable. We present the case of a 32-year-old man who sustained a left open grade 2 leg fracture and 18% to 20% second-degree superficial electrical flash burns on his right leg. Following primary management, skin testing for antibiotic sensitivity was performed, and prophylactic therapy with ceftriaxone, gentamycin, and metronidazole was initiated for the grossly contaminated wounds. On the second day of emergency admission, the patient developed hepatorenal dysfunction accompanied by severe thrombocytopenia (<30×103/mm3). The suspected antimicrobial agents were discontinued by the third day. Within 48 hours, the patient's hepatorenal function markedly improved; however, the blood dyscrasia progressed to severe pancytopenia over the next few days. Despite worsening parameters, the patient's vitals were maintained, and he exhibited no overt bleeding. On the fourth day, the patient developed opportunistic fungal bronchopneumonia, indicated by bilateral lower lobe infiltrates on chest x-ray and an elevated serum galactomannan level. He received supportive care, broad-spectrum antibiotics, and antifungal treatment, with a full recovery within 2 weeks. Antibiotic toxicity must be distinguished from other medical conditions to ensure appropriate management and a favorable prognosis.

ID Consultant: Laboratory Monitoring During Long-Term Use of Oral Antimicrobials in Pediatric Patients

Oral antimicrobials remain the mainstay of long-term treatment for many infections. Meanwhile, the use of oral agents is becoming commonplace for the treatment of several pediatric infections once managed exclusively with parenteral therapies. Unfortunately, antimicrobials are associated with several laboratory toxicities, particularly when high doses or combination therapies are used, but there is a paucity of data on optimal laboratory monitoring strategies. In this ID Consultant article, we offer a summary of the 3 most common laboratory-based toxicities seen with long-term use of oral antimicrobials-drug-induced kidney injury, liver injury, and hematological toxicities-and we provide our recommended approach to monitoring.

In-silico approaches to assessing multiple high-level drug-drug and drug-disease adverse drug effects

INTRODUCTION

Pharmacovigilance plays a pivotal role in monitoring adverse events (AEs) related to chemical substances in human/animal populations. With increasing spontaneous-reporting systems, researchers turned to in-silico approaches to efficiently analyze drug safety profiles. Here, we review in-silico methods employed for assessing multiple drug-drug/drug-disease AEs covered by comparative analyses and visualization strategies.

AREAS COVERED

Disproportionality, involving multi-stage statistical methodologies and data processing, identifies safety signals among drug-AE pairs. By stratifying data based on disease indications/demographics, researchers address confounders and assess drug safety. Comparative analyses, including clustering techniques and visualization techniques, assess drug similarities, patterns, and trends, calculate correlations, and identify distinct toxicities. Furthermore, we conducted a thorough Scopus search on 'pharmacovigilance,' yielding 5,836 publications spanning 2003 to 2023.

EXPERT OPINION

Pharmacovigilance relies on diverse data sources, presenting challenges in the integration of in-silico approaches and requiring compliance with regulations and AI adoption. Systematic use of statistical analyses enables identifications of potential risks with drugs. Frequentist and Bayesian methods are used in disproportionalities, each with its strengths and weaknesses. Integration of pharmacogenomics with pharmacovigilance enables personalized medicine, with AI further enhancing patient engagement. This multidisciplinary approach holds promise, improving drug efficacy and safety, and should be a core mission of One-Health studies.

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.

A Case Report of Ticagrelor-Induced Thrombocytopenia

Introduction

We report a case of new-onset thrombocytopenia following administration of a loading dose of ticagrelor.

Case Presentation

A 66-year-old male known to have diabetes mellitus type II, chronic obstructive airway disease, and hypertension presented to the emergency department with retrosternal chest pain and dyspnea. Work-up on presentation showed Hb 14.7 g/dL, platelet 229 × 10⁹/L, and troponin 309 ng/mL. The electrocardiogram showed ST elevation in the anterior-lateral leads. The patient underwent balloon angioplasty, and a drug-eluting stent was deployed. During the procedure, intravenous unfractionated heparin and a 180 mg loading dose of ticagrelor were given. Six hours post procedure, the platelet count was 70 × 10⁹/L without active bleeding. Blood smear was unremarkable, and no schistocytes could be seen. So, ticagrelor was stopped, and the patient's platelet count completely recovered four days after discontinuation.

Conclusion

Ticagrelor-induced thrombocytopenia is a rare but increasingly recognized entity. Therefore, post-treatment monitoring and early recognition are crucial parts of management.

A Case of COVID-19-Induced Immune Thrombocytopenia (ITP) in an Adult Female: An Under-Recognized Emerging Phenomenon

Coronavirus disease 2019 (COVID-19) follows a mild course in majority of cases, but some patients may develop non-pulmonary yet life-threatening complications. A Pandora's box had been opened when multisystem hyper-inflammatory syndromes and autoimmune diseases that had been described previously in children and young adults, that are associated with COVID-19, have now emerged in adults. They need to be recognized as important sequelae of severe COVID-19 disease. Immune thrombocytopenia (ITP) or thrombocytopenic purpura is an autoantibody and T-cell-mediated autoimmune disorder characterized by isolated thrombocytopenia, which can be triggered by different infections. First-line treatment of severe ITP includes platelet transfusions in life-threatening cases, followed by corticosteroids and intravenous immunoglobulins (IVIG). Since the beginning of the pandemic, more and more cases of COVID-19-associated ITP have been reported. We report a case of acquired ITP in a young woman that could only be attributed to her COVID-19 infection and was refractory to platelet transfusion, requiring further treatments. The aim of this report is to review some of the etiologies and purposed molecular mechanisms of the autoimmune nature of the disease and to focus on diagnosis and treatment. We will review the current literature surrounding this non-pulmonary manifestation of COVID-19 and current treatment options for this uncommon presentation of ITP.

Cross-reactivity between piperacillin-tazobactam and cefoperazone-sulbactam in drug-induced immune thrombocytopenia

Beta-lactam antibiotics commonly cause immune thrombocytopenia. Cross-reactivity in patients with drug-induced immune thrombocytopenia has rarely been reported. In this study, we describe the case of a 79-year-old man who developed thrombocytopenia after receiving piperacillin-tazobactam for an acute exacerbation of chronic obstructive pulmonary disease, and he was successfully treated with meropenem and cefotiam. However, thrombocytopenia recurred after cefoperazone-sulbactam administration. This indicated that cross-reactivity of platelet-specific antibodies occurred between piperacillin-tazobactam and cefoperazone-sulbactam. However, the responsible drug structures remain unknown, requiring further investigation. Likewise, chemical structure similarities among beta-lactam antibiotics must be examined to determine the risk of immune thrombocytopenia in the clinical setting.

Treatment of drug-induced immune thrombocytopenias

Several therapeutic agents can cause thrombocytopenia by either immune-mediated or non-immune-mediated mechanisms. Non-immune-mediated thrombocytopenia is due to direct toxicity of drug molecules to platelets or megakaryocytes. Immune-mediated thrombocytopenia, on the other hand, involves the formation of antibodies that react to platelet-specific glycoprotein complexes, as in classic drug-induced immune thrombocytopenia (DITP), or to platelet factor 4, as in heparin-induced thrombocytopenia (HIT) and vaccine-induced immune thrombotic thrombocytopenia (VITT). Clinical signs include a rapid drop in platelet count, bleeding or thrombosis. Since the patient's condition can deteriorate rapidly, prompt diagnosis and management are critical. However, the necessary diagnostic tests are only available in specialized laboratories. Therefore, the most demanding step in treatment is to identify the agent responsible for thrombocytopenia, which often proves difficult because many patients are taking multiple medications and have comorbidities that can themselves also cause thrombocytopenia. While DITP is commonly associated with an increased risk of bleeding, HIT and VITT have a high mortality rate due to the high incidence of thromboembolic complications. A structured approach to drug-associated thrombocytopenia/thrombosis can lead to successful treatment and a lower mortality rate. In addition to describing the treatment of DITP, HIT, VITT, and vaccine-associated immune thrombocytopenia, this review also provides the pathophysiological and clinical information necessary for correct patient management.

Treatment of chemotherapy-induced thrombocytopenia in patients with non-hematologic malignancies

Chemotherapy-induced thrombocytopenia (CIT) is a common complication of the treatment of non-hematologic malignancies. Many patient-related variables (e.g., age, tumor type, number of prior chemotherapy cycles, amount of bone marrow tumor involvement) determine the extent of CIT. CIT is related to the type and dose of chemotherapy, with regimens containing gemcitabine, platinum, or temozolomide producing it most commonly. Bleeding and the need for platelet transfusions in CIT are rather uncommon except in patients with platelet counts below 25x10⁹/L in whom bleeding rates increase significantly and platelet transfusions are the only treatment. Nonetheless, platelet counts below 70x10⁹/L present a challenge. In patients with such counts, it is important to exclude other causes of thrombocytopenia (medications, infection, thrombotic microangiopathy, post-transfusion purpura, coagulopathy and immune thrombocytopenia). If these are not present, the common approach is to reduce chemotherapy dose intensity or switch to other agents. Unfortunately decreasing relative dose intensity is associated with reduced tumor response and remission rates. Thrombopoietic growth factors (recombinant human thrombopoietin, pegylated human megakaryocyte growth and development factor, romiplostim, eltrombopag, avatrombopag and hetrombopag) improve pretreatment and nadir platelet counts, reduce the need for platelet transfusions, and enable chemotherapy dose intensity to be maintained. National Comprehensive Cancer Network guidelines permit their use but their widespread adoption awaits adequate phase III randomized, placebo-controlled studies demonstrating maintenance of relative dose intensity, reduction of platelet transfusions and bleeding, and possibly improved survival. Their potential appropriate use also depends on consensus by the oncology community as to what constitutes an appropriate pretreatment platelet count as well as identification of patient-related and treatment variables that might predict bleeding.

Detection of Drug-Induced Thrombocytopenia Signals in Children Using Routine Electronic Medical Records

Background: Drug-induced thrombocytopenia (DITP) is a severe adverse reaction and a significantly under-recognized clinical problem in children. However, for post-marketing pharmacovigilance purposes, detection of DITP signals is crucial. This study aimed to develop a signal detection model for DITP using the pediatric electronic medical records (EMR) data.

Methods: This study used the electronic medical records collected at Beijing Children’s Hospital between 2009 and 2020. A two-stage modeling method was developed to detect the signal of DITP. In the first stage, we calculated the crude incidence by mining cases of thrombocytopenia to select the potential suspected drugs. In the second stage, we constructed propensity score–matched retrospective cohorts of specific screened drugs from the first stage and estimated the odds ratio (OR) and 95% confidence interval (CI) using conditional logistic regression models. The novelty of the signal was assessed by current evidence.

Results: In the study, from a total of 839 drugs, 21 drugs were initially screened as potentially inducing thrombocytopenia. In total, we identified 18 positive DITP associations. Of these, potential DITP risk of nystatin (OR: 1.75, 95% CI: 1.37–2.22) and latamoxef sodium (OR: 1.61, 95% CI: 1.38–1.88) were two new DITP signals in both children and adults. Six associations between thrombocytopenia and drugs including imipenem (OR: 1.69, 95% CI: 1.16–2.45), teicoplanin (OR: 4.75, 95% CI: 3.33–6.78), fusidic acid (OR: 2.81, 95% CI: 2.06–3.86), ceftizoxime sodium (OR: 1.83, 95% CI: 1.36–2.45), ceftazidime (OR: 2.16, 95% CI: 1.58–2.95), and cefepime (OR: 5.06, 95% CI: 3.77–6.78) were considered as new signals in children.

Conclusion: This study developed a two-stage algorithm to detect safety signals of DITP and found eighteen positive signals of DITP, including six new signals in a pediatric population. This method is a promising tool for pharmacovigilance based on EMR data.

Bioactive Molecules Derived from Snake Venoms with Therapeutic Potential for the Treatment of Thrombo-Cardiovascular Disorders Associated with COVID-19

As expected, several new variants of Severe Acute Respiratory Syndrome-CoronaVirus-2 (SARS-CoV-2) emerged and have been detected around the world throughout this Coronavirus Disease of 2019 (COVID-19) pandemic. Currently, there is no specific developed drug against COVID-19 and the challenge of developing effective antiviral strategies based on natural agents with different mechanisms of action becomes an urgent need and requires identification of genetic differences among variants. Such data is used to improve therapeutics to combat SARS-CoV-2 variants. Nature is known to offer many biotherapeutics from animal venoms, algae and plant that have been historically used in traditional medicine. Among these bioresources, snake venom displays many bioactivities of interest such as antiviral, antiplatelet, antithrombotic, anti-inflammatory, antimicrobial and antitumoral. COVID-19 is a viral respiratory sickness due to SARS-CoV-2 which induces thrombotic disorders due to cytokine storm, platelet hyperactivation and endothelial dysfunction. This review aims to: (1) present an overview on the infection, the developed thrombo-inflammatory responses and mechanisms of induced thrombosis of COVID-19 compared to other similar pathogenesis; (2) underline the role of natural compounds such as anticoagulant, antiplatelet and thrombolytic agents; (3) investigate the management of coagulopathy related to COVID-19 and provide insight on therapeutic such as venom compounds. We also summarize the updated advances on antiviral proteins and peptides derived from snake venoms that could weaken coagulopathy characterizing COVID-19.

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

Comparison of Clinical Scoring Tools to Predict Heparin-Induced Thrombocytopenia in Cardiac Surgery

The 4Ts and HIT-Expert Probability (HEP) scoring tools for heparin-induced thrombocytopenia (HIT) have not been validated in cardiac surgery patients, and the reported sensitivity and specificity of the Post-Cardiopulmonary Bypass (CPB) scoring tool vary widely in the 2 available analyses. It remains unclear which of the available scoring tools most accurately predicts HIT in this population. Forty-nine HIT-positive patients who underwent on-pump cardiac surgery within a 6-year period were loosely matched to 98 HIT-negative patients in a 1:2 case-control design. The 4Ts, HEP, and CPB scores were calculated for each patient. Sensitivity and specificity of each tool were calculated using standard cut-offs. The Youden method was utilized to determine optimal cut-offs within receiver operating characteristic (ROC) curves of each score, after which sensitivities and specificities were recalculated. Using standard cut-offs, the sensitivities for the CPB, HEP, and 4Ts scores were 100%, 93.9%, and 69.4%, respectively. Specificities were 51%, 49%, and 71.4%, respectively. The AUC of the scoring tool ROC curves were 0.961 for the CPB score, 0.773 for the HEP score, and 0.805 for the 4Ts score. Using the Youden method-derived optimal cut-off of  ≥3 points on the CPB score, sensitivity remained 100% with improved specificity to 88.9%. The CPB score is the preferred HIT clinical scoring tool in adult cardiac surgery patients, whereas the 4Ts score performed less effectively. A cut-off of ≥ 3 points on the CPB score could increase specificity while preserving high sensitivity, which should be validated in a prospective evaluation.

Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immune checkpoint inhibitor-related adverse events

Immune checkpoint inhibitors (ICIs) are the standard of care for the treatment of several cancers. While these immunotherapies have improved patient outcomes in many clinical settings, they bring accompanying risks of toxicity, specifically immune-related adverse events (irAEs). There is a need for clear, effective guidelines for the management of irAEs during ICI treatment, motivating the Society for Immunotherapy of Cancer (SITC) to convene an expert panel to develop a clinical practice guideline. The panel discussed the recognition and management of single and combination ICI irAEs and ultimately developed evidence- and consensus-based recommendations to assist medical professionals in clinical decision-making and to improve outcomes for patients.

A practical approach to evaluating postoperative thrombocytopenia

Identifying the cause(s) of postoperative thrombocytopenia is challenging. The postoperative period includes numerous interventions, including fluid administration and transfusion of blood products, medication use (including heparin), and increased risk of organ dysfunction and infection. Understanding normal thrombopoietin physiology and the associated expected postoperative platelet count changes is the crucial first step in evaluation. Timing of thrombocytopenia is the most important feature when differentiating causes of postoperative thrombocytopenia. Thrombocytopenia within 4 days of surgery is commonly caused by hemodilution and increased perioperative platelet consumption prior to thrombopoietin-induced platelet count recovery and transient platelet count overshoot. A much broader list of possible conditions that can cause late-onset thrombocytopenia (postoperative day 5 [POD5] or later) is generally divided into consumptive and destructive causes. The former includes common (eg, infection-associated disseminated intravascular coagulation) and rare (eg, postoperative thrombotic thrombocytopenic purpura) conditions, whereas the latter includes such entities as drug-induced immune thrombocytopenia or posttransfusion purpura. Heparin-induced thrombocytopenia is a unique entity associated with thrombosis that is typically related to intraoperative/perioperative heparin exposure, although it can develop following knee replacement surgery even in the absence of heparin exposure. Very late onset (POD10 or later) of thrombocytopenia can indicate bacterial or fungal infection. Lastly, thrombocytopenia after mechanical device implantation requires unique considerations. Understanding the timing and severity of postoperative thrombocytopenia provides a practical approach to a common and challenging consultation.

Treatment with eltrombopag of severe immune thrombocytopenia and hemolytic anemia associated with COVID-19 pneumonia: a case report

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19). Whether SARS-CoV-2 can trigger an autoimmune reaction against platelets and red blood cells remains unclear. Herein, we report a case of COVID-19 pneumonia associated with severe immune thrombocytopenia and hemolytic anemia. An 83-year-old woman was admitted to the hospital because of both dyspnea and diffuse mucocutaneous bleeding. Exams revealed hemolytic anemia (HA), severe immune thrombocytopenia (ITP), and bilateral pneumonia. Molecular testing confirmed a diagnosis of COVID-19 pneumonia. Thrombocytopenia did not respond to first-line treatment with immunoglobulin, corticosteroids, and platelet transfusions. Addition to therapy of the thrombopoietin receptor agonist, eltrombopag, resulted in full recovery. COVID-19 can be associated with ITP and HA. There are neither guidelines nor clinical experience on the treatment of COVID-19-associated ITP and our case, showing complete response to eltrombopag, may help clinicians in their practice during the COVID-19 pandemic.

PLAIN LANGUAGE SUMMARY

The case of an 83-year-old woman with COVID-19 pneumonia associated with two severe blood diseases that cause platelet and red cell destruction Coronavirus disease 2019 (COVID-19) is caused by a virus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We do not know exactly whether this virus can stimulate our immune system to react against platelets and red blood cells. Herein, we report a case of COVID-19 pneumonia associated with two severe blood diseases, immune thrombocytopenia, which causes platelet destruction, and hemolytic anemia, which causes red cell destruction. An 83-year-old woman was admitted to the hospital because of both difficulty in breathing and diffuse bleeding in mucosae and skin. Exams revealed hemolytic anemia, severe immune thrombocytopenia, and pneumonia in both lungs. Molecular testing confirmed a diagnosis of COVID-19 pneumonia. The first treatment with immunoglobulin, corticosteroids, and platelet transfusions was not enough to cure thrombocytopenia; the addition of eltrombopag which acts on the thrombopoietin receptor agonist resulted in full recovery. COVID-19 can be present together with immune thrombocytopenia and hemolytic anemia. As there are no guidelines on the treatment of immune thrombocytopenia in patients with COVID-19 and the clinical experience is limited, the complete response achieved with eltrombopag may help clinicians in their practice during the COVID-19 pandemic.

Preoperative hematocrit and platelet count are associated with blood loss during spinal fusion for children with neuromuscular scoliosis

AIM

To assess the relationship of preoperative hematology laboratory results with intraoperative estimated blood loss and transfusion volumes during posterior spinal fusion for pediatric neuromuscular scoliosis.

METHODS

Retrospective chart review of 179 children with neuromuscular scoliosis undergoing spinal fusion at a tertiary children's hospital between 2012 and 2017. The main outcome measure was estimated blood loss. Secondary outcomes were volumes of packed red blood cells, fresh frozen plasma, and platelets transfused intraoperatively. Independent variables were preoperative blood counts, coagulation studies, and demographic and surgical characteristics. Relationships between estimated blood loss, transfusion volumes, and independent variables were assessed using bivariable analyses. Classification and Regression Trees were used to identify variables most strongly correlated with outcomes.

RESULTS

In bivariable analyses, increased estimated blood loss was significantly associated with higher preoperative hematocrit and lower preoperative platelet count but not with abnormal coagulation studies. Preoperative laboratory results were not associated with intraoperative transfusion volumes. In Classification and Regression Trees analysis, binary splits associated with the largest increase in estimated blood loss were hematocrit ≥44% vs. <44% and platelets ≥308 vs. <308 × 10⁹/L.

CONCLUSIONS

Preoperative blood counts may identify patients at risk of increased bleeding, though do not predict intraoperative transfusion requirements. Abnormal coagulation studies often prompted preoperative intervention but were not associated with increased intraoperative bleeding or transfusion needs.

Evolving Role of Pharmacogenetic Biomarkers to Predict Drug-Induced Hematological Disorders

ABSTRACT

Drug-induced hematological disorders constitute up to 30% of all blood dyscrasias seen in the clinic. Hematologic toxicity from drugs may range from life-threatening marrow aplasia, agranulocytosis, hemolysis, thrombosis to mild leukopenia, and thrombocytopenia. Pathophysiologic mechanisms underlying these disorders vary from an extension of the pharmacological effect of the drug to idiosyncratic and immune-mediated reactions. Predicting these reactions is often difficult, and this makes clinical decision-making challenging. Evidence supporting the role of pharmacogenomics in the management of these disorders in clinical practice is rapidly evolving. Despite the Clinical Pharmacology Implementation Consortium and Pharmacogenomics Knowledge Base recommendations, few tests have been incorporated into routine practice. This review aims to provide a comprehensive summary of the various drugs which are implicated for the hematological adverse events, their underlying mechanisms, and the current evidence and practical recommendations to incorporate pharmacogenomic testing in clinical care for predicting these disorders.

Outcomes of patients with thrombocytopenia evaluated at hematology subspecialty clinics

BACKGROUND

Thrombocytopenia is a frequently encountered laboratory abnormality and a common reason for hematology referrals. Workup for thrombocytopenia is not standardized and frequently does not follow an evidence-based algorithm. We conducted a systematic analysis to evaluate the laboratory testing and outcomes of patients evaluated for thrombocytopenia at hematology clinics in a tertiary referral center between 2013 and 2016.

PATIENT AND METHODS

We performed a comprehensive chart review for patients evaluated for thrombocytopenia during the study period. Patients were followed for 1 year from the initial hematology evaluation and assessed for the development of a hematologic malignancy, rheumatologic, or infectious diseases among other clinical outcomes.

RESULTS

We evaluated 472 patients with a median (range) age of 61 (17-94) years. The majority (63.8%) had mild thrombocytopenia. Within 1 year of follow-up, 14 patients (3.0%) were diagnosed with a hematologic malignancy. A higher likelihood of developing a hematologic malignancy was noted in patients with concurrent leukopenia (hazard ratio [HR] 9.97, 95% confidence interval [CI] 3.28-30.32, p < .01) and increasing age (HR per 10-year deciles 1.52, 95% CI 1.03-2.25, p = .03). In patients with asymptomatic isolated mild thrombocytopenia, laboratory testing did not reveal any significant positive findings and patients did not receive any new major diagnosis during the follow-up period.

CONCLUSION

Our findings provide basis and call for development of an evidence-based algorithmic approach for evaluation of patients with thrombocytopenia, testing, and referrals. It also supports a conservative approach mainly driven by physical exam signs, symptoms, and other laboratory findings for patients with isolated mild thrombocytopenia.

Platelet transfusion refractoriness: how do I diagnose and manage?

Platelet refractoriness continues to be a problem for thrombocytopenic patients because the risk of a major spontaneous or life-threatening bleed significantly increases when platelet counts drop below 10 × 109/L. The majority of patients have nonimmune causes driving the refractoriness, such as bleeding, medications, or diffuse intravascular coagulation; however, this article is dedicated to the diagnosis and support of patients with immune-based platelet refractoriness. Antibodies to class I HLA molecules (A and B alleles) are responsible for most immune-based refractory cases, with antibodies to platelet antigens seen much less frequently. Patients may be supported with either crossmatch-compatible or HLA-matched/compatible platelet units. When trying to select HLA units it can be difficult to find a perfect "4 of 4" match for the patient's class IA and IB alleles. In these cases, it is better to use the antibody specificity prediction method, which identifies compatible units that lack antigens recognized by the patient's anti-HLA antibodies. For an algorithmic approach to the patient with platelet refractoriness, see Visual Abstract.

Recurrent acute pancreatitis induced by 5-ASA and azathioprine in ulcerative colitis

Drug-induced acute pancreatitis (DIAP) is an often-neglected entity where the disorder is the consequence of the toxic effects of various agents applied to treat potentially life-threatening conditions, such as inflammatory bowel disease. Here, we present the case of a male patient with ulcerative colitis with a history of two episodes of recurrent acute pancreatitis. After excluding other potential causes, we suspected DIAP since the patient received 5-aminosalycilate (5-ASA) prior to the first episode and, one year later, azathioprine (AZA) prior to the second episode. The causative effect of AZA was confirmed by performing a re-challenge with a reduced dose. While both episodes of DIAP had a mild disease course, they were associated with acute relapse of ulcerative colitis. Last seen, the patient was asymptomatic. With this case, we would like to highlight the importance and diagnostic difficulties of DIAP in the background of recurrent cases when common etiological factors of acute pancreatitis are excluded.

Naproxen-induced thrombocytopenia

Thrombocytopenia has many mechanisms with broad differentials. A detailed history and physical, with timely diagnostic testing, is necessary to parse out the underlying etiology. Clinicians should maintain a high suspicion for drug-induced thrombocytopenia when there is an acute drop in the platelet level after exposure to commonly implicated drugs. Drug-induced thrombocytopenia is not well defined, as reporting is voluntary and not critically reviewed. Oftentimes, the culprit is not the drug itself, but a drug metabolite, which is difficult to prove with drug-dependent antibody testing. Here we present a case where naproxen led to hemarthrosis secondary to drug-induced thrombocytopenia.

Pathophysiology and Diagnosis of Drug-Induced Immune Thrombocytopenia

Drug-induced immune thrombocytopenia (DITP) is a life-threatening clinical syndrome that is under-recognized and difficult to diagnose. Many drugs can cause immune-mediated thrombocytopenia, but the most commonly implicated are abciximab, carbamazepine, ceftriaxone, eptifibatide, heparin, ibuprofen, mirtazapine, oxaliplatin, penicillin, quinine, quinidine, rifampicin, suramin, tirofiban, trimethoprim-sulfamethoxazole, and vancomycin. Several different mechanisms have been identified in typical DITP, which is most commonly characterized by severe thrombocytopenia due to clearance and/or destruction of platelets sensitized by a drug-dependent antibody. Patients with typical DITP usually bleed when symptomatic, and biological confirmation of the diagnosis is often difficult because detection of drug-dependent antibodies (DDabs) in the patient's serum or plasma is frequently not possible. This is in contrast to heparin-induced thrombocytopenia (HIT), which is a particular DITP caused in most cases by heparin-dependent antibodies specific for platelet factor 4, which can strongly activate platelets in vitro and in vivo, explaining why affected patients usually have thrombotic complications but do not bleed. In addition, laboratory tests are readily available to diagnose HIT, unlike the methods used to detect DDabs associated with other DITP that are mostly reserved for laboratories specialized in platelet immunology.

DNA damage and inflammatory response in workers exposed to fuels and paints

Workers exposed to fuels and paints may present alterations in several parameters. Thus, we assessed potential biomarkers, with the aim of detecting early changes in gasoline station attendants and painters. Blood samples were collected for the analysis of inflammatory and DNA damage markers, besides biochemical, haematological and oxidative stress parameters. Biochemical and haematological parameters, which are assessed with routine exams, showed few changes. However, these findings could mask the workers' real health status. Besides, markers of oxidative damage were not modified. Levels of inflammatory parameters (cytokines and nitric oxide levels) and the DNA damage marker 8-hydroxydeoxyguanosine were significantly changed in the workers. Our results suggest that inflammatory and DNA damage parameters can be potential biomarkers for the biological monitoring of workers exposed to fuels and paints and may contribute to the development of occupational protection standards.

Drug-Induced Immune Thrombocytopenia From Administration of a Local Anesthetic Agent Resulting in Splenectomy

Thrombocytopenia is a common clinical condition, and drug-induced immune thrombocytopenia (DITP) should be considered in hospitalized patients with severe thrombocytopenia who are exposed to new medications. The potential mechanism is described to be drug-triggered antibody-mediated platelet destruction causing petechiae and mucosal bleeding. Severe form of DITP can be refractory to systemic steroids and even intravenous immunoglobulin administration. Such cases usually require splenectomy for definitive treatment. A number of substances including medications, herbal remedies, and even food items have been identified with a definitive or probable causal role in DITP. However, it is rarely reported from locally administered medications such as local anesthetic drugs. We present a unique case of severe DITP from lidocaine that resulted in refractory DITP requiring splenectomy for definitive treatment. 

Phenytoin Seizure Prophylaxis Therapy Resulting in Severe Thrombocytopenia After Brain Tumor Debulking Surgery

Patient: Male, 40-year-old

Final Diagnosis: Phenytoin-induced thrombocytopenia

Symptoms: Thrombocytopenia

Medication: Phenytoin

Clinical Procedure: Tumor debulking surgery

Specialty: Neurosurgery

Thrombocytopenia associated with clonidine in a case of clozapine-induced sialorrhea

Clozapine is approved by the US Food and Drug Administration for treatment-resistant schizophrenia and mitigation of suicidality in patients with schizophrenia or schizoaffective disorder. Clozapine requires monitoring of adverse events, such as hypotension, myocarditis, cardiomyopathy, seizures, severe neutropenia, and gastrointestinal hypomotility. Sialorrhea is another adverse event that can be bothersome for patients and result in nonadherence or the development of aspiration pneumonia. Clonidine, an α_2A adrenergic receptor agonist, is one medication option that can reduce or eliminate sialorrhea. Clonidine is generally well tolerated but can contribute to hypotension and sedation. One adverse event associated with clonidine not described in the literature is thrombocytopenia. Reported is a case of clonidine-associated thrombocytopenia when used for the treatment of clozapine-induced sialorrhea.

Thrombocytopenia in the Intensive Care Unit

The evaluation and management of thrombocytopenia is a daily challenge for clinicians in the intensive care unit (ICU). Thrombocytopenia is incredibly common, present in upwards of 60% of ICU patients. Additionally, thrombocytopenia in the critically ill is rarely caused by a single etiology. Several causes of thrombocytopenia in the ICU including heparin-induced thrombocytopenia (HIT) and thrombotic thrombocytopenic purpura demand urgent recognition and intervention. This chapter provides a general overview of thrombocytopenia in the ICU and highlights important diagnostic and management considerations for some of the most common etiologies.

Azithromycin-Induced Thrombocytopenia: A Rare Etiology of Drug-Induced Immune Thrombocytopenia

Drug-induced thrombocytopenia requires a high suspicion for diagnosis and a broad investigation to exclude other etiologies of low platelets. Cessation of the offending agent often results in recovery of platelet counts. Many medications are known to cause a degree of thrombocytopenia. We present a rare case of severe thrombocytopenia associated with administration of azithromycin.

From Discovery of Snake Venom Disintegrins to A Safer Therapeutic Antithrombotic Agent

Snake venoms affect blood coagulation and platelet function in diverse ways. Some venom components inhibit platelet function, while other components induce platelet aggregation. Among the platelet aggregation inhibitors, disintegrins have been recognized as unique and potentially valuable tools for examining cell–matrix and cell–cell interactions and for the development of antithrombotic and antiangiogenic agents according to their anti-adhesive and anti-migration effect on tumor cells and antiangiogenesis activities. Disintegrins represent a family of low molecular weight, cysteine-rich, Arg-Gly-Asp(RGD)/Lys-Gly-Asp(KGD)-containing polypeptides, which inhibit fibrinogen binding to integrin αIIbβ3 (i.e., platelet glycoprotein IIb/IIIa), as well as ligand binding to integrins αvβ3, and α5β1 expressed on cells (i.e., fibroblasts, tumor cells, and endothelial cells). This review focuses on the current efforts attained from studies using disintegrins as a tool in the field of arterial thrombosis, angiogenesis, inflammation, and tumor metastasis, and briefly describes their potential therapeutic applications and side effects in integrin-related diseases. Additionally, novel R(K)GD-containing disintegrin TMV-7 mutants are being designed as safer antithrombotics without causing thrombocytopenia and bleeding.

Management of immune thrombocytopenia in elderly patients

Despite the improvement in understanding its pathogenesis and the introduction of novel treatment options, the management of primary immune thrombocytopenia (ITP) still remains challenging. Considering its increased incidence with aging and prolonged life-expectancy, ITP is often diagnosed in elderly patients, a subset that deserves some special precautions. Ensure the diagnosis is a crucial step, and carefully attention must be given in excluding other causes of thrombocytopenia, especially among older people that frequently suffer from many comorbidities. When it comes to treatment decision, it is worth keeping into account that the elderly have an increased risk of bleeding, thrombosis and infections, that they often require many concomitant therapies, including antiplatelet or anticoagulant agents, and that treatment-related toxicities are often increased and sometimes more dangerous that the disease itself. There are not dedicated guidelines, and only few specific studies. Steroids with or without IVIG remain the first-line treatment. Splenectomy is less effective than in youngers and burdened by an increased thrombotic and infectious risk. Rituximab is a good option in non-immunocompromised patients, but long-term remissions are few. Eltrombopag and romiplostim have a good safety and efficacy profile, and have become a prominent drug in this subset, even if they are associated with a possible increased risk of thrombosis, and long-term toxicity is unknown. Other drugs, such as dapsone and danazol, have a well-known efficacy and safety profile, and still represent a valid option among elderly patients.

Risk factors for bleeding, including platelet count threshold, in newly diagnosed immune thrombocytopenia adults

Essentials Risk factors of bleeding in adult immune thrombocytopenia are not known. This multicenter study assessed risk factors of bleeding at immune thrombocytopenia onset. Platelet count thresholds associated with bleeding were < 20 × 109 L-1 and < 10 × 109 L-1 . Exposure to anticoagulants was a major risk factor of severe bleeding.

SUMMARY

Background The aim of this cross-sectional study was to assess risk factors for bleeding in immune thrombocytopenia (ITP) adults, including the determination of platelet count thresholds. Methods We selected all newly diagnosed ITP adults included in the Cytopénies Auto-immunes Registre Midi-PyrénéEN (CARMEN) register and at the French referral center for autoimmune cytopenias. The frequencies of any bleeding, mucosal bleeding and severe bleeding (gastrointestinal, intracranial, or macroscopic hematuria) at ITP onset were assessed. Platelet count thresholds were assessed by the use of receiver operating characteristic curves. All potential risk factors were included in logistic regression models. Results Among the 302 patients, the frequencies of any, mucosal and severe bleeding were 57.9%, 30.1%, and 6.6%, respectively. The best discriminant threshold of platelet count for any bleeding was 20 × 109 L-1 . In multivariate analysis, factors associated with any bleeding were platelet count (< 10 × 109 L-1 versus ≥ 20 × 109 L-1 , odds ratio [OR] 48.2, 95% confidence interval [CI] 20.0-116.3; between 10 × 109 L-1 and 19 × 109 L-1 versus ≥ 20 × 109 L-1 , OR 5.2, 95% CI 2.3-11.6), female sex (OR 2.6, 95% CI 1.3-5.0), and exposure to non-steroidal anti-inflammatory drugs (NSAIDs) (OR 4.8, 95% CI 1.1-20.7). A low platelet count was also the main risk factor for mucosal bleeding. Exposure to anticoagulant drugs was associated with severe bleeding (OR 4.3, 95% CI 1.3-14.1). Conclusions Platelet counts of < 20 × 109 L-1 and < 10 × 109 L-1 were thresholds for major increased risks of any and mucosal bleeding. Platelet count, female sex and exposure to NSAIDs should be considered for assessment of the risk of any bleeding. Exposure to anticoagulant drugs was a major risk factor for severe bleeding.

A study paradigm integrating prospective epidemiologic cohorts and electronic health records to identify disease biomarkers

Defining the full spectrum of human disease associated with a biomarker is necessary to advance the biomarker into clinical practice. We hypothesize that associating biomarker measurements with electronic health record (EHR) populations based on shared genetic architectures would establish the clinical epidemiology of the biomarker. We use Bayesian sparse linear mixed modeling to calculate SNP weightings for 53 biomarkers from the Atherosclerosis Risk in Communities study. We use the SNP weightings to computed predicted biomarker values in an EHR population and test associations with 1139 diagnoses. Here we report 116 associations meeting a Bonferroni level of significance. A false discovery rate (FDR)-based significance threshold reveals more known and undescribed associations across a broad range of biomarkers, including biometric measures, plasma proteins and metabolites, functional assays, and behaviors. We confirm an inverse association between LDL-cholesterol level and septicemia risk in an independent epidemiological cohort. This approach efficiently discovers biomarker-disease associations.

Biomarker identification requires prohibitively large cohorts with gene expression and phenotype data. The approach introduced here learns polygenic predictors of expression from genetic and expression data, used to infer biomarker levels in patients with genetic and disease information.

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.

Clinical Practice Updates in the Management Of Immune Thrombocytopenia

Immune thrombocytopenia (ITP), previously called idiopathic thrombocytopenia purpura, is an autoimmune disorder characterized by a severe reduction in peripheral blood platelet count. In healthy individuals, normal platelet count ranges from 150-450 × 10⁹/L, while in thrombocytopenia counts fall to less than 100 × 10⁹/L.1 In adults, the incidence of ITP is approximately two to four per 100,000.2,3 Bleeding risks, specifically hemorrhage and intracranial hemorrhage, represent the most serious complications for patients with ITP. Over the past decade, the understanding of ITP has expanded greatly, which has contributed to a number of updates in the diagnosis and treatment of the disorder.3 This article aims to briefly review the pathophysiology of ITP and summarize updates in ITP management and treatment options in the adult population.

Severe Thrombocytopenia in Adults with Severe Acute Respiratory Distress Syndrome: Impact of Extracorporeal Membrane Oxygenation Use

Extracorporeal membrane oxygenation (ECMO) use is perceived to cause thrombocytopenia (T), but the role of non-ECMO factors in the development of T remains unclear. We sought to evaluate the incidence and factors associated with severe T (platelet count ≤ 50,000/μl) in adults with severe acute respiratory distress syndrome (ARDS) managed with or without ECMO. The ECMO (n = 32) versus the non-ECMO (n = 53) groups had a similar baseline platelet count (214,000 vs. 179,000/μl), Acute Physiology and Chronic Health Evaluation (APACHE) II score (p = 0.13), unfractionated heparin (UFH) exposure (p = 0.62), and severe T incidence (25 vs. 19%, p = 0.5). Although the APACHE II score (p = 0.01), presence of liver failure (p = 0.08), and platelet transfusion (p = 0.0009) were different between the severe T (18/85 [21%]) and non-severe T groups (67/85 [79%]), the incidence of septic shock (p = 0.64), heparin infusion use (p = 0.41), exposure to non-heparin T-causing medications (p = 0.77) and ECMO use (p = 0.5) were not. An adjusted multivariate linear regression model revealed that only the APACHE II score was independently associated with the development of severe T (p = 0.01) but use of ECMO was not (p = 0.32) ECMO use may not affect the incidence of severe T among adults with severe ARDS. Larger studies that are prospective in nature are required to confirm this finding.

Palatal Petechiae in the Absence of Group A Streptococcus in Pediatric Patients with Acute-Onset Neuropsychiatric Deterioration: A Cohort Study

BACKGROUND

Palatal petechiae are 95% specific for streptococcal pharyngitis. Despite this, and despite prior research demonstrating that Group A Streptococcus (GAS) is a common antecedent to pediatric acute-onset neuropsychiatric syndrome (PANS) episodes, we anecdotally observed a low rate of documented GAS in patients with PANS and palatal petechiae. This retrospective chart review was conducted to formally report the rate of palatal petechiae and concurrent GAS in a cohort of patients with PANS and investigate other etiologic factors.

METHODS

The clinical notes of 112 patients seen at the Stanford PANS Clinic who met PANS research criteria were reviewed for mention of palatal petechiae. The medical records of patients who demonstrated palatal petechiae on physical examination were reviewed for signs of infection, a clinical history of trauma, and laboratory results that could indicate other causes of petechiae.

RESULTS

Twenty-three patients had documented palatal petechiae on physical examination (ages 5-16, 13/23 [57%] male). Fifteen patients had a rapid GAS test and GAS culture in the Stanford PANS clinic, all with negative results. Evidence of recent GAS infection was found in 8/23 (32%) patients (elevated GAS titers [n = 6] or documentation of a positive rapid GAS test at another facility [n = 2]), one of whom also had potential herpes simplex virus (HSV) infection. One patient had potential HSV infection and recent palatal trauma. No patients had thrombocytopenia. 14/23 (61%) of patients with palatal petechiae had no discernable cause of petechiae. 10/19 (53%) of patients had antihistone antibodies.

CONCLUSIONS

Despite the established relationship between palatal petechiae and GAS, no patient with palatal petechiae in our clinic tested positive for GAS and only 32% had evidence of recent GAS. Most did not have an identifiable cause for the palatal lesions. This finding suggests the potential for alternative causes of palatal petechiae or undetectable GAS in our patient population. The high prevalence of palatal petechiae without GAS infection suggests that the pathogenesis of PANS is multifactorial and may involve disruption or inflammation of the microvasculature. Additional research is needed to further elucidate these findings.

Treatment of Pneumocystis jirovecii pneumonia in HIV-infected patients: a review

INTRODUCTION

Pneumocystis pneumonia is a potentially life-threatening pulmonary infection that occurs in immunocompromised individuals and HIV-infected patients with a low CD4 cell count. Trimethoprim-sulfamethoxazole has been used as the first-line agent for treatment, but mutations within dihydropteroate synthase gene render potential resistance to sulfamide. Despite advances of combination antiretroviral therapy (cART), Pneumocystis pneumonia continues to occur in HIV-infected patients with late presentation for cART or virological and immunological failure after receiving cART. Areas covered: This review summarizes the diagnosis and first-line and alternative treatment and prophylaxis for Pneumocystis pneumonia in HIV-infected patients. Articles for this review were identified through searching PubMed. Search terms included: 'Pneumocystis pneumonia', 'Pneumocystis jirovecii pneumonia', 'Pneumocystis carinii pneumonia', 'trimethoprim-sulfamethoxazole', 'primaquine', 'trimetrexate', 'dapsone', 'pentamidine', 'atovaquone', 'echinocandins', 'human immunodeficiency virus infection', 'acquired immunodeficiency syndrome', 'resistance to sulfamide' and combinations of these terms. We limited the search to English language papers that were published between 1981 and March 2017. We screened all identified articles and cross-referenced studies from retrieved articles. Expert commentary: Trimethoprim-sulfamethoxazole will continue to be the first-line agent for Pneumocystis pneumonia given its cost, availability of both oral and parenteral formulations, and effectiveness or efficacy in both treatment and prophylaxis. Whether resistance due to mutations within dihydropteroate synthase gene compromises treatment effectiveness remains controversial. Continued search for effective alternatives with better safety profiles for Pneumocystis pneumonia is warranted.

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.

Thrombocytopenia

Thrombocytopenia is a commonly encountered hematologic problem in inpatient and ambulatory medicine. The many underlying mechanisms of thrombocytopenia include pseudothrombocytopenia, splenic sequestration, and marrow underproduction and destruction. This article presents the known causes of thrombocytopenia, a framework for evaluation, and brief descriptions of management in a case-based format.