Type Of Thrombocytopenia Research Articles

Examining the Relationship between Severity of Thrombocytopenia and the Pattern of Malaria: A Hospital-Based Study

OBJECTIVES To determine the association between the severity of thrombocytopenia and the pattern of malaria. METHODOLOGY This descriptive cross-sectional study included 194 patients who tested positive for malarial parasites on peripheral smear examination. The study comprised smear-positive malaria cases, both males and females, who were Pakistani nationals aged between 8 and 50. Exclusion criteria were individuals with dengue, typhoid, immunocompromised status, liver disease, and pregnancy. Data were recorded for age, gender, the pattern of malaria (Plasmodium (P). vivax, P. falciparum, or mixed), and type of thrombocytopenia (mild, moderate, and severe). The association between the severity of thrombocytopenia and the pattern of malaria was determined using a chi-square test, with the analysis stratified by gender. RESULTSThe mean age of the participants was 28.58±11.70 years, with 114 (58.76%) being male. The lowest platelet count (64,627 ± 43,062) was found in cases of falciparum malaria, while the highest mean platelet count was found in cases of vivax malaria (130,919 ± 107,723), and this difference was statistically significant (p=0.004). The most common occurrence of severe thrombocytopenia was in falciparum malaria cases (n=11, 42.31%), and the difference was statistically significant (p=0.024). CONCLUSION Falciparum malaria has the lowest mean platelet count and more severe thrombocytopenia than vivax and mixed type.

Measurement of immature platelet fraction is useful in the differential diagnosis of MYH9 disorders.

Although the presence of large and giant platelets is important in screening for MYH9 disorders, platelet morphology evaluation is dependent on operator subjectivity. Immature platelet fraction (IPF%) is widely used in clinical practice because of its rapidity and reproducibility; however, IPF% has been rarely analyzed in MYH9 disorders. Therefore, our study aimed to clarify the usefulness of IPF% in the differential diagnosis of MYH9 disorders. We assessed 24 patients with MYH9 disorders, 10 with chronic immune thrombocytopenia (cITP), 14 with myelodysplastic syndromes (MDS) with thrombocytopenia (<100 × 109 /L), and 20 healthy volunteers. Platelet-related data, including IPF% and platelet morphology (diameter, surface area, and staining), were retrospectively analyzed. Median IPF% in MYH9 disorders, 48.7%, was significantly higher than in all other groups (cITP: 13.4%, MDS: 9.4%, controls: 2.6%). IPF% in MYH9 disorders was significantly negatively correlated with platelet count and significantly positively correlated with the diameter and surface area of platelets, but a correlation was not found between IPF% and platelet staining. The area under the curve of IPF% for the differential diagnosis of MYH9 disorders was 0.987 (95% CI: 0.969-1.000), with a sensitivity of 95.8% and specificity of 93.2% when the cutoff value of IPF% was 24.3%. Our study strongly suggests that IPF% is useful in the differential diagnosis between MYH9 disorders and other types of thrombocytopenia.

Thrombocytopenia and Retina

Platelets play a role in blood coagulation and wound healing. Thrombocytopenia is defined as a platelet count of less than 150000/mm3 in the peripheral blood. The most common cause of thrombocytopenia is increased destruction. Ocular involvement is rare in thrombocytopenia, and bleeding is the most common complication. The increased tendency to thrombosis observed in some types of thrombocytopenia causes occlusion in retinal arterioles, and this results in retinal ischemia. Combined systemic and ocular interventions are used in the treatment.

Applications of Artificial Intelligence in Thrombocytopenia

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

A Rare Case of Vancomycin-Induced Immune Thrombocytopenia

Vancomycin-induced immune thrombocytopenia (ITP) is a rare type of drug-induced immune thrombocytopenia (DITP) that can lead to life-threatening consequences as a result of its use. We herein report a case of a 74-year-old male with a history of diabetes mellitus type II, Alzheimer’s disease, and stroke who presented to the ICU with sepsis. The patient was on heparin for 20 days prior to presentation, with platelet levels at the time within normal limits as per his baseline. Following the introduction of vancomycin to his clinical regimen in the treatment of sepsis, the patient developed a significant drop in platelet count from 400 x10³/mm³ to 70 x10³/mm³. Discontinuation of the drug leads to improvement of the platelet counts confirming the diagnosis of vancomycin-induced ITP.

Gestational Thrombocytopenia: A Review on Recent Updates.

Thrombocytopenia is a condition in which the blood platelet count is low. It is well established that the mild thrombocytopenia frequency is higher in normal pregnancy. This type of thrombocytopenia was named pregnancy-induced thrombocytopenia. However, recently, it has been widely known as gestational thrombocytopenia (GT). The rate is higher in women with a prior GT history and multiple pregnancies. However, it appears that GT is a physiological response to the pregnancy; placenta's peculiar structure and its unique blood flow pattern play major roles in GT development. There are no specific, precise, or known underlying pathophysiological mechanisms of GT, and no new specific management strategies are published yet. Therefore, we decided to do a non-systematic review of any recent updates that had been published in PubMed, EMBASE, and Web of Science about the pathophysiology of GT, its treatment, and other related topics.

Development of an Automated Chemiluminescent Enzyme Immunoassay for Measuring Thrombopoietin in Human Plasma.

Plasma thrombopoietin (TPO) measurements help distinguish between different types of thrombocytopenia but are not feasible in routine clinical practice. We developed a fully automated quantitative chemiluminescent enzyme immunoassay (CLEIA) for measuring TPO (TPO-CLEIA), which is a one-step sandwich-type assay. This assay utilizes a mouse monoclonal capture antibody, which has the neutralizing epitope of the interaction between TPO and the TPO receptor, and a newly generated rabbit monoclonal detector antibody. In analytical performance studies, this assay showed good linearity over the measuring range and high sensitivity. The limit of quantification (LoQ) of this assay was 3.4 pg/mL; low TPO concentration values of almost all healthy individuals exceeded the LoQ value. In clinical validation studies, TPO levels obtained from patients with aplastic anemia (AA) significantly increased, whereas those of patients with immune thrombocytopenia (ITP) were normal or slightly increased. The cutoff value for TPO-CLEIA corresponding to the previously reported values was useful for distinguishing between ITP and AA. These results suggest that TPO-CLEIA can quantify human plasma TPO levels with high accuracy and sensitivity and has the potential to facilitate routine clinical measurement of TPO in patients with various types of thrombocytopenia.

Clot Waveform Analysis Demonstrates Low Blood Coagulation Ability in Patients with Idiopathic Thrombocytopenic Purpura.

Background: Although platelets, which contain large amounts of phospholipids, play an important role in blood coagulation, there is still no routine assay to examine the effects of platelets in blood coagulation. Methods: Hemostatic abnormalities in patients with thrombocytopenia, including those with idiopathic thrombocytopenic purpura (ITP), were examined using clot wave analysis (CWA)–small-amount tissue-factor-induced FIX activation (sTF/FIXa) and thrombin time (TT). Results: Although there were no marked differences in the three parameters of activated partial thromboplastin time (APTT) between normal healthy volunteers and typical patients with ITP, the peak heights of the CWA-sTF/FIXa were markedly low in patients with ITP. The three peak times of the CWA-sTF/FIXa in patients with a platelet count of ≤8.0 × 1010/L were significantly longer than those in patients with a platelet count > 8.0 × 1010/L and the peak heights of the CWA-sTF/FIXa in patients with a platelet count of ≤8.0 × 1010/L were significantly lower than those in patients with >8.0 × 1010/L. The peak heights of the CWA-APTT in patients with ITP were significantly lower than in patients with other types of thrombocytopenia. The three peak heights of the CWA-sTF/FIXa in ITP patients were significantly lower than those in patients with other types of thrombocytopenia. The CWA-TT showed lower peak heights and longer peak times in patients with ITP in comparison to patients with other types of thrombocytopenia. Conclusions: The CWA-sTF/FIXa and CWA-TT results showed that blood coagulation is enhanced by platelets and that the blood coagulation ability in ITP patients was low in comparison to healthy volunteers and patients with other types of thrombocytopenia.

Thrombocytopenia in pregnant women.

Thrombocytopenia is one of the two most common hematological problems in pregnant women. It is defined as the platelet (PLT) count below 150 × 103/μL. Gestational incidental thrombocytopenia (GIT) represents about 75% of thrombocytopenia cases in pregnancy and it is believed that GIT is secondary to accelerated platelet destruction and increased plasma volume associated with pregnancy. The pregnancy complications such as preeclampsia and its most severe form - HELLP syndrome account for 20% cases of thrombocytopenia in pregnancy and primary immune thrombocytopenic purpura (ITP) - for 3-4 percent. During ITP, maternal antiplatelet antibodies can pass through the placenta and bind to fetal thrombocytes leading to the development of fetal thrombocytopenia which occurs in about 50% cases. Even if the maternal platelet count stabilizes, the estimated fetal and neonatal risk of thrombocytopenia in ITP is approximately 30%. Other types of thrombocytopenia in pregnant women constitute 1-2% of cases (disseminated intravascular coagulation, autoimmunological diseases, congenital, infection and drug-related, concomitant with blood neoplastic diseases). Although thrombocytopenia in pregnant women usually has a mild course, in case of a significant decrease in PLT count may lead to dangerous bleeding, especially when the platelet count falls below 20 × 103/μL. Since it is important to identify the cause of thrombocytopenia and to determine the risk for both the mother and the child, this paper presents the influence of maternal thrombocytopenia on the pregnancy course as well as its etiology and diagnostics. The treatment principles are discussed.

Platelet indices in differentiating hypoproductive and hyperdestructive thrombocytopenia

The volume indices of the platelets are very easily available and this is considered very useful in diagnosing thrombocytopenia. There are only a handful studies which have reported platelet indices which would be very useful in differentiating different types of thrombocytopenia. This study is one such noble attempt to find whether this is actually useful in the initial evaluation of patients with thrombocytopenia using the platelet indices.

COMPARISON OF PLATELET INDICES IN HYPOPRODUCTIVE AND HYPERDESTRUCTIVE THROMBOCYTOPENIA

Background: Thrombocytopenia is one of the most common haematological disorders and is also a life-threatening condition. The two types of thrombocytopenia, hypoproductive and hyperdestructive can best be distinguished by bone marrow examination; but it is an invasive, time-consuming and expensive process. The aim of this study was to determine the role of platelets indices in distinguishing between the two types which is a cost-effective and non-invasive modality of investigations. Methods: It was a cross-sectional study, conducted in the Pathology Laboratory, Rehman Medical Institute, Peshawar, conducted from 1st July 2019 to 30th June 2020. Non-probability convenience sampling technique was used. Sample size was calculated using WHO formula, and a total of 74 thrombocytopenic patients referred for bone marrow aspirate and trephine biopsy were included in the study. Clinical record, complete blood count (CBC) and bone marrow trephine biopsy were obtained and computed. Results: Mean Platelet Volume was 10.57±1.33 fl in hypoproductive group and 11.637±1.98 fl in hyperdestructive group. The difference between the groups was statistically significant (p=0.017). Platelet Distribution Width was 12.68±3.16 fl in hypoproductive group and 14.811±3.61 fl in hyperdestructive group (p=0.014). Platelet Large Cell Ratio was 30.81±9.23% in hypoproductive group and 36.993±10.25% in hyperdestructive group (p=0.010). Conclusion: Platelet indices can be used as a reliable tool for distinguishing between hypoproductive and hyperdestructive thrombocytopenia. Pak J Physiol 2021;17(2):3–6

Maternal and fetal outcome of pregnancies complicated with thrombocytopenia

Thrombocytopenia is defined as a platelet count below the lower limit of normal range (typically &amp;#60; 150,000/ microL). It is second only to anemia as the most common hematological abnormality encountered during pregnancy. Thrombocytopenia complicates about 7-8% of all pregnancies, especially in third trimester; it most frequently represents a complication not requiring treatment. Evaluation and management of thrombocytopenia during pregnancy and postpartum may be challenging because there are many potential causes, some directly related to pregnancy and some unrelated. For many causes there are no diagnostic laboratory tests.This topic reviews our approaches to determining causes of thrombocytopenia in a pregnant women and its impact on newborns while looking to stratify the risk according to etiology and severity of parturient’s hematological condition.In our study Gestational thrombocytopenia was the commonest cause of thrombocytopenia with incidence of 70%, followed by Preeclampsia (22%), HELLP (4%), ITP (2%) and Dengue (2%).Gestational thrombocytopenia is the commonest cause of thrombocytopenia and may not be related to adverse pregnancy outcome, thus can be treated as benign condition. Clinical assessment is most important factor for evaluating a patient with thrombocytopenia.Monitoring of platelet count of pregnant women should be a routine at antenatal visits for timely diagnosis and to achieve favorable feto- maternal outcome in all types of thrombocytopenia. Neonatal platelet count should be done in all mothers diagnosed with thrombocytopenia.After detailed evaluation of the data, we came to the conclusion that with proper care and precautions, readiness to deal with complications, thrombocytopenia does not pose significant impact on maternal and fetal morbidity and mortality when compared to normal population.

Problems of hematological toxicity during the treatment of blood system malignancies

Background. Treatment of blood malignancies is often accompanied by the hematological toxicity. Thrombocytopenia is one of the most common phenomena, which can be caused by pseudothrombocytopenia, production deficiency or increased destruction of platelets, their pathological distribution or aggregation.&#x0D; Objective. To determine the features of hematological toxicity in the treatment of malignant blood diseases.&#x0D; Materials and methods. Analysis of literature data and recommendations on this topic.&#x0D; Results and discussion. Diagnosis of thrombocytopenia involves a detailed study of a peripheral blood smear to assess the morphology of all cells, as well as additional studies (determination of lactate dehydrogenase, D-dimer, fibrinogen, etc.; aspiration and bone marrow biopsy; virological and bacteriological studies; clinical examination). The main causes of thrombocytopenia in cancer patients are chemotherapy (ChT) and radiation therapy (RT), however, the diagnosis should take into account all possible nosological options. The assessment should be performed if the platelet count is &lt;100,000/μl. The normal lifespan of platelets is 8-10 days, so after many types of ChT thrombocytopenia develops about 7th days after treatment, reaches a maximum of 14th days and ends in 28-35th days. After RT thrombocytopenia usually starts in 7-10th days after its termination and is present during 30-60 days. Before treating thrombocytopenia, the need for ChT should be re-evaluated and the risk of bleeding assessed, and the ChT regimen should be changed if possible. If the risk of bleeding is high or the platelet count is critically low, platelet transfusion is prescribed, however, it has recently been found that absolute platelet count is not a predictor of bleeding risk in this patient population (PLADO study). In addition, platelet transfusion is limited in resources and costly, and is accompanied by the risk of side effects (acute lung damage due to transfusion, fever, bacterial sepsis, development of transfusion intolerance). This became the basis for the search for alternative treatment options. Recombinant interleukin-11 (oprelvekin) reduces the need for platelet transfusion from 96 to 70 % of patients on ChT. However, although this drug is FDA-approved, it is characterized by a large number of side effects. In turn, thrombopoietin receptor agonists (subcutaneous romiplostin, oral eltrombopag) bind to the corresponding receptors and increase the number of platelets in the blood. The effectiveness of treatment is within 70 %. Emaplag (“Yuria-Pharm”) is the first and only eltrombopag in Ukraine. Emaplag is indicated for the treatment of thrombocytopenia caused by ChT in patients with solid tumors, patients with platelet counts &lt;50×109/L, and in cases where the physician decides to increase platelet count. With regard to anemias, their main causes in cancer patients are the factors of the underlying disease (bone marrow infiltration, infectious processes), the impact of ChT or RT, other causes (malnutrition, bleeding, renal dysfunction). Examination of patients with anemia should include history taking, evaluation of blood smear and iron metabolism, exclusion of occult gastrointestinal bleeding and renal failure, Coombs’ test, determination of endogenous erythropoietin. Treatment options for ChT-induced anemia include blood transfusions and the use of erythropoietins (epoetins α and β, darbepoetin) with or without iron supplements (oral or intravenous). The advantages of using erythropoietin include reducing the need for transfusion of erythrocyte mass, a gradual increase in hemoglobin, increasing quality of life. However, erythropoietins are not recommended for use in cancer patients who do not receive ChT or receive RT, because in these cases, their use is associated with an increased mortality risk. Because in some patient groups erythropoietins accelerate tumor growth or reduce survival, the patient must give a written informed consent for their use. Given these data, it is advisable to prescribe intravenous iron, as it allows not only to quickly increase hemoglobin and improve quality of life, but also to reduce the dosage of erythropoietins. Iron carboxymaltose if the most modern parenteral iron preparation. It is characterized by low toxicity and high stability.&#x0D; Conclusions. 1. Thromboconcentrate transfusion is a fast and effective way to correct thrombocytopenia, which has a number of disadvantages. 2. Thrombopoietin receptor agonists (eltrombopag) make it possible to increase the effectiveness of treatment without interrupting the planned therapy. 3. In the presence of anemia, all possible causes should be corrected before prescribing erythropoietins. 4. If the anemia is caused by ChT, the patient needs to take erythropoietins. 5. Addition of intravenous iron preparations to erythropoietin therapy significantly increases the effectiveness of treatment.

A characteristic flow cytometric pattern with broad forward scatter and narrowed side scatter helps diagnose immune thrombocytopenia (ITP).

Various disorders cause severe thrombocytopenia, which can lead to critical hemorrhage. Procedures that rapidly support the diagnosis and risk factors for serious bleeding were explored, with a focus on immune thrombocytopenia (ITP). Twenty-five patients with thrombocytopenia, including 13 with newly diagnosed ITP, 3 with chronic ITP, 6 with aplastic anemia (AA), and 3 with other thrombocytopenia (one acute myeloid leukemia, one acute lymphoblastic leukemia, and one hemophagocytic lymphohistiocytosis), were reviewed. In addition to platelet-related parameters obtained by an automated hematology analyzer, flow cytometric analysis of platelets was performed. A characteristic flow cytometric pattern with broad forward scatter and narrowed side scatter, which is specific to ITP, but not other types of thrombocytopenia, was found. CD62P-positive platelets were increased in newly diagnosed ITP cases compared to control (P < 0.0001), AA (P = 0.0032). Moreover, detection of dramatic changes in these parameters on sequential monitoring may suggest internal hemorrhage, even absent skin or visible mucosal bleeding. The bleeding score for visible mucosae had a negative correlation with platelet count and a positive correlation with immature platelet fraction (%), forward scatter, and CD62P. This characteristic flow cytometric pattern makes it possible to distinguish ITP from other thrombocytopenic disorders.

A Model for Studying the Hemostatic Consumption or Destruction of Platelets

A fundamental issue in understanding homeostasis of the hematopoietic system is to what extent intrinsic and extrinsic factors regulate cell fate. We recently revisited this issue for the case of blood platelets and concluded that platelet life span is largely regulated by internal factors, in contrast to the long-held view that accumulated damage from the environment triggers clearance. However, it is known that in humans there is an ongoing fixed requirement for platelets to maintain hemostasis and prevent bleeding; hence a proportion of platelets may be consumed in such processes before the end of their natural life span. Whether it is possible to detect this random loss of platelets in normal individuals at steady-state is unknown. To address this question, we have developed a mathematical model that independently incorporates age-independent random loss and age-dependent natural senescent clearance. By fitting to population survival curves, we illustrate the application of the model in quantifying the fixed requirement for platelets to maintain hemostasis in mice, and discuss the relationship with previous work in humans. Our results suggest a higher requirement for platelets in mice than in humans, however experimental uncertainty in the data limits our ability to constrain this quantity. We then explored the relationship between experimental uncertainty and parameter constraint using simulated data. We conclude that in order to provide useful constraint on the random loss fraction the standard error in the mean of the data must be reduced substantially, either through improving experimental uncertainty or increasing the number of experimental replicates to impractical levels. Finally we find that parameter constraint is improved at higher values of the random loss fraction; thus the model find utility in situations where the random loss fraction is expected to be high, for example during active bleeding or some types of thrombocytopenia.

Adekvatna evaluacija trombocitopenija kao preduslov uspešnog lečenja kardioloških bolesnika

Awareness of the basic pathogenetic mechanisms of thrombocytopenia occurence is a prerequisite to adequate treatment of complex cardiac patients. Introducing percutaneous coronary interventions along with both standard and novel antithrombotic drugs has significantly improved an acute coronary syndrome patients' prognosis, though it has also additionaly increased the risk for developing new types of thrombocytopenia, etiologically completely divergent but with the common denominator of substantially affecting new complication development and a rise in mortality. The most common thrombocytopenias occuring in consequence of percutaneous coronary interventions are induced mostly by heparin, GP IIb/IIIa inhibitors and iodinated contrast. Besides a well-known fact that a number of thrombocytopenias potentially lead to haemorrhagic syndrome, physicians must be fully conscious that there is a group of diseases manifested by thrombocytopenia also representing a primarily thrombotic risk factor, with the specific clinical significance being attached to antiphospholipid syndrome, heparin-induced thrombocytopenia type II as well as thrombotic thrombocytopenic purpura. Due to the possiblity of fast development of complications, a physician is obliged to detect this disease in a timely manner using adequate laboratory monitoring, define its cause and take appropriate measures, with particular stress placed on therapeutic treatment individualisation considering the great clinical complexity of these patients.

Consensus Guidelines for Periprocedural Management of Coagulation Status and Hemostasis Risk in Percutaneous Image-guided Interventions

From the Division of Vascular and Interventional Radiology, Jefferson Radiology, Hartford Hospital, 85 Seymour St, Ste 200, Hartford, CT 06106 (P.C.M.); Department of Radiology, Boston Healthcare System, VAMC Boston, Massachusetts (C.J.G.); Department of Medical Imaging, Scarborough General Hospital, Richmond Hill, Ontario, Canada (S.K.); Department of Radiology, GI/GU Division, Massachusetts General Hospital, Boston, Massachusetts (D.A.G.); Department of Radiology and Radiologic Sciences, Uniformed Services University of the Health Sciences and Department of Radiology, National Naval Medical Center, Bethesda, Maryland (D.L.M.); RADIA, Everett, Washington (R.B.O.); Department of Radiology, University of Florida, Gainesville, Florida (D.W.P.); Department of Medical Imaging, Division of Vascular and Interventional Radiology, University of Toronto, University Health Network, Toronto, Ontario, Canada (D.K.R.); Department of Interventional Radiology, The Reading Hospital and Medical Center, West Reading, Pennsylvania (D.S.); Radiology Associates of Central Florida, Mt Dora, Florida (M.S.S.); Mallinckrodt Institute of Radiology, St Louis, Missouri (D.A.Z.); and Geisinger System Radiology, Geisinger Health System, Danville, Pennsylvania (J.F.C.). Received November 18, 2008; accepted November 24, 2008. Address correspondence to P.C.M.; E-mail: pmalloy@ jeffersonradiology.com

A prospective evaluation of normal mean platelet volume in discriminating hyperdestructive thrombocytopenia from hypoproductive thrombocytopenia

Bone marrow (BM) examination is the gold standard test in discriminating between hyperdestructive thrombocytopenia and hypoproductive thrombocytopenia. However, this procedure is invasive. Mean platelet volume (MPV) is simple and may be used as an alternative diagnostic test in distinguishing these two types of thrombocytopenia. All thrombocytopenic patients (platelet count: <150.0 x 10(9)/l), except those with congestive splenomegaly, thrombotic thrombocytopenic purpura, and disseminated intravascular coagulopathy, were enrolled into the study prospectively. The mean MPV of normal Thais (7.9 fl) was tested as a cutoff value. Any thrombocytopenic patient with MPV of >7.9 fl would be presumptively diagnosed as hyperdestructive thrombocytopenia, whereas one with MPV of <or= 7.9 fl would be presumptively diagnosed as hypoproductive thrombocytopenia. One hundred two patients were completely evaluated. When compared with the BM examination, the MPV of >7.9 fl could predict hyperdestructive thrombocytopenia with a sensitivity of 82.3% (95% CI: 70.5-90.8), a specificity of 92.5% (95% CI: 79.6-98.4), a positive predictive value of 94.4% (95% CI: 84.6-98.8), a negative predictive value of 77.1% (95% CI: 62.7-88.0), and a likelihood ratio of 11.0. In conclusion, the mean MPV of normal Thais may be used as a cutoff value in distinguishing these two types of thrombocytopenia.

The Bcl-2 Family Protein Inhibitor, ABT-263, Promotes Apoptotic-Like Response in Isolated Platelets.

Platelets are relatively short-lived, anucleated cells derived from megakaryocytes that are essential for proper hemostasis. Although they lack a nucleus, platelets possess a highly organized structure with multiple cellular organelles including mitochondria and a number of specific granules. Upon recruitment to sites of endothelial injury, platelet activation stimulates their adhesion, aggregation and release of granule components leading to coagulation. Many of the cellular changes observed during platelet activation and platelet senescence resemble those observed during apoptosis in nucleated cells, including loss of mitochondrial membrane potential, caspase activation, phosphatidylserine (PS) externalization, cell shrinkage and microparticle formation (analogous to membrane blebbing). ABT-263 is an orally bioavailable Bcl-2 family protein inhibitor currently in clinical development. This compound is a potent antagonist of the anti-apoptotic proteins Bcl-xL, Bcl-2 and Bcl-w and induces apoptosis in cancer cells dependent on these proteins for survival. ABT-263 induces a unique thrombocytopenia in multiple species that is characterized by a rapid clearance of circulating platelets with recovery to normal platelet counts within several days after treatment cessation. To elucidate the mechanisms underlying this thrombocytopenia, a series of in vitro experiments were performed using freshly isolated platelets comparing ABT-263, its enantiomer (which has significantly lower activity against Bcl-2 family proteins) and known platelet activators. ABT-263, but not the enantiomer control, reduced the viability of dog and human platelets and activated key apoptotic processes, including cytochrome c release, caspase 3 activation, and PS externalization. ABT-263 did not induce aggregation of isolated platelets and did not induce surface expression of GPIIb/IIIa that is essential for platelet adhesion to fibrinogen during clot formation. While ABT-263 had no effect on markers of lysosomal- or alpha-granule release, increases in a marker of dense granule release were apparent at high concentrations. Taken together these data suggest that ABT-263 induces an apoptotic-like response in platelets that is distinct from platelet activation. Furthermore, the lack of effect of the enantiomer control compound suggests this effect is mediated through inhibition of antiapoptotic Bcl-2 family members. Loss of membrane asymmetry and PS externalization has been suggested to be the primary signal for the recognition and clearance of senescent platelets by phagocytes of the reticuloendothelial system. Induction of apoptosis in platelets by Bcl-2 family protein inhibitors such as ABT-263 may coopt this process inducing a premature platelet senescence resulting in a novel type of thrombocytopenia, in vivo.

Thrombocytopenia Probably Heparin-Induced in Women with Tumor of the Heart and Pulmonary Embolism

43 years old women with tumor of the right ventricle was admitted to ICU due to pulmonary embolism and suspicion for heparin-induced thrombocytopenia. Thrombocytopenia was successfully treated with Arixtra and the patient was qualified for the cardio surgery intervention. Heparin is widely used in treatment and prophylaxis of venous thromboembolism and other diseases. One of the most important adverse effect of treatment with heparin is heparin-inducted thrombocytopenia (HIT), which is one of the most frequent drug-induced, immune-mediated type of thrombocytopenia. If it is unrecognized is associated with significant morbidity and mortality. According to our knowledge this is first report of Arixtra usage in patient with suspicion of HIT in Poland.