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PubMed1998

Thrombocytosis as a prognostic factor in endometrial carcinoma.

We reviewed the prevalence of thrombocytosis (platelet count >/=400, 000/microL) and its association with outcome in 135 consecutive endometrial carcinoma patients and compared the platelet count with other prognostic factors. Nineteen of 135 patients (14%) had thrombocytosis. Thrombocytosis was significantly more frequent in advanced disease (stage II-IV), unfavorable grade (G2 and G3), deep myometrial invasion, and lymph-vascular space invasion. The overall 5-year survival rate was 92%. The 5-year survival rate of the 19 patients with thrombocytosis was significantly worse than that of the patients without thrombocytosis (61 vs 96%, P < 0.0001). The recurrence rate was significantly higher in patients with thrombocytosis than in those with a platelet count <400,000/microL (7 vs 32%, P < 0.005). In a multivariate analysis, thrombocytosis continued to be a predictor of worse prognosis. In conclusion, we found thrombocytosis to be a prognostic factor for survival in patients with endometrial carcinoma.

Adult↗
PubMed2003

Reactive thrombocytosis without endothelial damage does not affect the microvascular anastomotic patency.

There is still controversy about the correlation of thrombocytosis and thrombosis complication. Using a rodent splenectomy-induced thrombocytosis model and a thrombogenic endothelial damage model (inverted suture resulting in an intraluminal thrombogenic adventitia of divided femoral artery), the authors investigated whether reactive thrombocytosis with or without endothelial damage contributes to the patency of microvascular anastomosis. Four experimental groups were evaluated in this study: 1) sham operation without thrombogenic anastomosis after femoral artery division; 2) sham operation with thrombogenic anastomosis; 3) thrombocytosis alone without thrombogenic anastomosis; 4) thrombocytosis with thrombogenic anastomosis (each subgroup n = 10, total N = 40). Vascular patency was assessed after immediate operation and on the seventh day postoperatively. Platelet counts and platelet activation (CD62P) were studied in correlation to microvascular patency. In rats without thrombogenic anastomosis groups, there were no significant differences in CD62P expression on platelets (p = 0.09), the patency rates (p = 0.561), or perfusion units (p = 0.746) before and after arterial reanastomosis between rats with and without thrombocytosis, respectively. However, the thrombogenic anastomosis of femoral artery in thrombocytosis and control groups showed significantly increased CD62P expression (p < 0.05), decreased the perfusion unit (p < 0.05), and patency rate (p < 0.001), compared with rats without thrombogenic anastomosis of femoral artery in both groups. In summary, this study demonstrates that microvascular anastomosis can be performed safely with reactive thrombocytosis alone without thrombogenic anastomosis. Meticulous microvascular anastomosis without triggering platelet activation is the most important factor to prevent thrombosed vessels in microsurgical anastomosis.

Anastomosis, Surgical↗
PubMed1998

Thrombocytosis in childhood.

INTRODUCTION: Thrombocytosis is a common condition in infancy and childhood. There are very few paediatric literature on its incidence and clinical significance. METHOD: We conducted a prospective study over 18 months (January 1993 to June 1994) on all patients admitted with a platelet count done. Cases with platelet count > 600 x 10(9)/L were reviewed and followed-up. Serial platelet count were done at 1 week, 2 weeks, 3 weeks, 4 weeks, and then monthly until it normalised. RESULTS: One hundred and thirty-five cases out of 10,288 admissions had raised platelet count. There was a preponderance of male (sex ratio M:F = 1.7:1). Majority was less than 1 year old. Seventy-eight percent had associated infection of which 2/3 were due to bacterial infections, Pneumonia was the most common bacterial infection associated with thrombocytosis whilst gastroenteritis was the most common cause for non-bacterial infection and Kawasaki's disease constituted the majority of the non-infective etiology. Cases with platelet count > 900 x 10(9)/L, 73.3% were due to bacterial infection. Three cases of Kawasaki's disease had platelet counts > 900 x 10(9)/L. Fifty-two percent of cases developed thrombocytosis within 4 days of illness. In nonbacterial infection, the thrombocytosis normalised by about 1 week after onset. For bacterial infection, the thrombocytosis normalised later depending on the severity of infection. In majority of the Kawasaki's disease, the platelet count normalised by the third week. CONCLUSION: Primary thrombocytosis is rare in paediatric age group. None of the cases developed any symptoms associated with thrombocytosis. Secondary thrombocytosis is a benign and common phenomenon in children.

Age Distribution↗
PubMed1999

5-year incidence of thrombocytosis and the effect on heparin dose response and heparin requirements.

Thrombocytosis has been shown to be associated with heparin resistance. Contact activation of platelets results in release of Platelet Factor 4 from alpha granules present in the platelet cytoplasm. Platelet Factor 4 is a cationic substance that neutralizes heparin. This could result in inadequate heparinization during cardiopulmonary bypass (CPB). Inability to adequately anticoagulate patients with thrombocytosis could result in a poor clinical outcome. A retrospective review of pump records from 1991 to 1996 was used to assess the frequency of thrombocytosis, describe the demographic characteristics of patients with thrombocytosis, and determine the effects on patient heparin dose response (HDR) and additional heparin requirements. A platelet count of 400,000/mm3 was chosen as a cut-off for thrombocytosis. Of the 3281 patients undergoing CPB during this time period, a total of 571 patients were included in this review: 99 had high platelet counts. The over-all prevalence of thrombocytosis during this time period was 3.0%. Patients with thrombocytosis tended to be younger (p = .02), have lower preoperative HCT (p < .001), and weigh less (p < .001). These patients had lower post-heparin loading dose ACTs, lower HDR, required more additional heparin to reach an ACT of 480 sec before CPB, and required more heparin on CPB to maintain the ACT > 480 sec (p < .05). Multiple linear regression was performed and concluded that age, use of NTG and heparin drip preoperatively, and platelet count were significant predictors of the heparin dose response. Use of plasmapheresis to remove platelet-rich plasma (PRP) before CPB was performed in 22 patients, six of whom had high platelet counts. In these patients, removal of PRP resulted in no difference in the amount of additional heparin required pre-CPB to reach an ACT of 480 sec. (p = NS) Additional studies are needed to determine whether use of plasmapheresis is a cost-effective and clinically useful option in patients with thrombocytosis.

Aged↗
PubMed1999

Thrombocytosis in women with vulvar carcinoma.

Thrombocytosis (platelet count >400 x 10(9)/L) is frequently found in association with malignant disease. Although the pathogenesis of thrombocytosis in malignancy is currently unclear, it appears to be a poor prognostic factor in patients with lung, colon, breast, and cervical carcinoma. The current study was initiated to assess the incidence of thrombocytosis in vulvar carcinoma and to evaluate its prognostic significance for patients with vulvar carcinoma. The pretreatment platelet counts of 201 women treated for vulvar cancer were reviewed and correlated to the patient's age, stage of disease, node status, histologic type, and outcome. Differences between categories were analyzed by means of the ANOVA test, and survival was compared using the log-rank test on the Kaplan-Meier life table. Thrombocytosis was presented in 14.92% of patients with vulvar malignancies and in 15.46% of patients with squamous cell carcinoma of the vulva. No correlation was found between thrombocytosis and tumor size, incidence of lymph node metastases, or stage of the disease. The 5-year survival rate for patients with thrombocytosis was 89.29%, which was not significantly different from the 76.47% 5-year survival of patients with normal platelet counts (P = 0.586). When adjusted for age, histological differentiation, number of tumors, staging, incidence of nodal metastases, platelet count, hemoglobin, and white blood count, only the staging, number of tumors, and histological differentiation were associated with an unfavorable prognosis (P = 0.0001, P = 0.003, P = 0.03, respectively). Thrombocytosis was not found to be a prognostic factor in patients with carcinoma of the vulva in this series of 201 patients.

Adult↗
PubMed1995

Elevated plasma thrombopoietic activity in patients with metastatic cancer-related thrombocytosis.

BACKGROUND AND PURPOSE: High platelet counts are occasionally seen in patients suffering from progressive malignant disorders. While granulocyte colony-stimulating factor (G-CSF) has been implicated in paraneoplastic leukemoid reactions, the stimulus for thrombocytosis is unknown. Our purpose in this study was to determine if plasma from cancer patients with thrombocytosis contains a factor or factors with thrombopoietic activity. METHODS: We tested the effects of plasma obtained from 5 individuals with advanced tumors and high platelet counts and from 4 patients with advanced cancer and normal platelet counts on megakaryocytic differentiation of two megakaryoblastic cell lines (Dami and HEL). Differentiation was evaluated by assessing the expression of the platelet-specific cell-surface antigens CD41 (HUPL-mI) and glycoprotein IIb-IIIa using an immunocytochemical staining score. In addition, plasma samples from 7 of the 9 patients and from 5 additional cancer patients with thrombocytosis were assayed for the levels of interleukin (IL)-3, IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), G-CSF, and IL-1 beta protein using an enzyme-linked immunosorbent assay (ELISA). RESULTS: Expression of platelet-specific cell-surface antigen was increased in HEL cells after exposure to plasma from all 5 of the cancer patients with thrombocytosis, and in Dami cells after exposure to plasma from 4 of the 5. Similar, but less significant, results were found when these cells were incubated with control combinations of recombinant GM-CSF plus IL-6 or of IL-3 plus IL-6. Platelet-specific cell-surface-antigen expression was not increased in HEL or Dami cells after exposure to the plasma from the 4 cancer patients with normal platelet counts or to normal control plasma. ELISA revealed elevated levels of IL-6 in the plasma from 4 patients with thrombocytosis (38, 40, 63, and 99 pg/mL). In addition, GM-CSF concentration was high in 3 of these 4 patients (33, 47, and 127 pg/mL), and the G-CSF level was elevated in 1 (543 pg/mL). IL-1 beta and IL-3 levels were undetectable. CONCLUSIONS: Our data suggest that the thrombocytosis observed in individuals with advanced malignant disease is mediated by a humoral mechanism. Levels of IL-6, GM-CSF, and G-CSF are elevated in some of these patients, but the plasma concentrations are generally lower than those required for in vitro induction of megakaryocytic differentiation. Plasma from patients with paraneoplastic thrombocytosis may therefore contain thrombopoietins that have not yet been identified, and which might have clinical usefulness.

Adult↗
PubMed1997

Thrombopoietin levels in patients with primary and reactive thrombocytosis.

Human c-mpl ligand or thrombopoietin (TPO) has been proved to be a critical cytokine in the physiological regulation of thrombopoiesis. Previous evidence suggested that TPO production is constitutive and TPO plasma levels are regulated by the platelet-megakaryocyte mass through c-mpl receptor-mediated uptake and metabolism. To evaluate whether this mechanism of TPO level regulation is also operative in subjects with an elevated platelet count, we evaluated serum TPO in 32 patients with thrombocytosis due to essential thrombocythaemia (ET) or polycythaemia vera (PV) and in 70 subjects with reactive thrombocytosis; 32 healthy subjects were also studied. TPO levels were significantly higher in the ET and PV groups (median 246.2 pg/ml, range 93.5-4596) and reactive thrombocytosis patients (median 287 pg/ml, range 82.7-1960.0) than in normal subjects (median 156.7 pg/ml, range 62.2-352.7). No significant difference was found between the two groups of patients, indicating that serum TPO levels cannot differentiate between primary and reactive thrombocytosis. No significant correlation was found between platelet count and TPO levels in either ET-PV or reactive thrombocytosis, whereas a trend toward a correlation between acute-phase reactants and TPO was observed in patients with reactive thrombocytosis. These results indicate that TPO clearance by platelets-megakaryocytes is not fully operative or is not the only mechanism of TPO level regulation in primitive and reactive thrombocytosis.

Acute-Phase Reaction↗
PubMedDate not supplied

Thrombocytosis in 24 horses (1989-1994).

The records of horses presented to the Veterinary Teaching Hospital of North Carolina State University College of Veterinary Medicine between January 1, 1989 and April 30, 1994 were evaluated to determine risk factors associated with thrombocytosis. Of the 2,346 horses for which a CBC was performed, 24 (1.0%) had a platelet count > 400,000/microL. Demographic, diagnostic, physical examination, and clinicopathologic variables from these cases were compared with a reference population consisting of 189 horses with a normal platelet count presenting during the same period. Infectious/ inflammatory disorders were observed more commonly in horses with high platelet counts than in horses with normal platelet counts. Initial independent evaluation of demographic variables revealed that horses more than 3 years of age, females, and geldings were less likely to have thrombocytosis than were younger horses or stallions. Independent analysis of clinicopathologic variables revealed that horses with thrombocytosis were more likely to have hyperfibrinogenemia, leukocytosis, hypoproteinemia, and anemia than were horses with normal platelet counts. Physical examination parameters associated with thrombocytosis included tachycardia and pyrexia. In the final multivariable model, the variables with the strongest association with thrombocytosis included leukocytosis, anemia, and hyperfibrinogenemia. Thrombocytosis rarely causes clinical problems in horses and is not likely to require specific antiplatelet therapy. The strong association of thrombocytosis with infectious/inflammatory disorders, however, should lead clinicians to suspect these types of conditions in horses with high platelet counts.

Anemia↗
PubMed2003

Impact of pretreatment thrombocytosis on survival in primary breast cancer.

Platelet count has been reported to have predictive value in various cancer entities. In the case of breast cancer, evidence about involvement of platelets is still incomplete. Our objective was to assess the influence of pretreatment thrombocytosis on survival and establish its prognostic relevance for breast cancer patients. We performed a retrospective, multivariate analysis of 4,300 patients with early-stage breast cancer. All subjects participated in one of five prospective, randomized, multicenter trials conducted by the Austrian Breast and Colorectal Cancer Study Group. Thrombocytosis was defined as a platelet count exceeding 400 G/L. Median follow-up was 52 months. Univariate and multiple Cox regression models were calculated for overall survival (OS), breast cancer-related survival and disease-free survival (DFS). Pretreatment thrombocytosis was observed in 161 patients (3.7%). Estimated median OS, breast cancer-related survival and DFS for patients with versus those without thrombocytosis was 71.0 versus 99.5, 72.0 versus 100.9, and 80.4 versus 88.4 months, respectively (p = 0.0054, p = 0.0095, p = 0.0199). A multiple Cox regression model including tumor and nodal status, grading, age, hormone receptor status and pretreatment thrombocytosis identified pretreatment thrombocytosis as an independent predictive factor for OS (p = 0.0064) and breast cancer-related survival (p = 0.0162). Multivariate analysis failed to identify pretreatment thrombocytosis as an independent risk factor for DFS (p = 0.1355). In our retrospective study, elevated platelet counts at time of diagnosis were associated with poor prognosis in breast cancer. We hypothesize that platelets may contribute to the pathophysiology of hematogenous metastasis.

Aged↗
PubMed1990

Prolonged thrombocytosis in mice after 5-fluorouracil results from failure to down-regulate megakaryocyte concentration. An experimental model that dissociates regulation of megakaryocyte size and DNA content from megakaryocyte concentration.

Rodents treated with 150 mg/kg of 5-fluorouracil (5-FU) exhibit a marked and prolonged rebound thrombocytosis, suggesting that feedback control of one or more megakaryocyte characteristics (size, polyploidy, or concentration) is altered. To determine the changes in megakaryocytes that lead to such a profound thrombocytosis, C3H mice were injected with 150 mg/kg 5-FU, and platelet and megakaryocyte responses were examined at frequent intervals from days 1 through 25. After 5-FU injection, all megakaryocyte indices decreased, as did platelet number. However, the decrease in platelets to one third of control was greater than the decreases in megakaryocyte indices, suggesting that thrombocytopoiesis was ineffective from days 3 through 7 post 5-FU. Megakaryocyte size began to recover on day 4, followed by polyploid DNA content on day 5, and megakaryocyte concentration and platelets at 7.5 days. Megakaryocyte size peaked on days 6 through 8 (1.25 x normal), followed by megakaryocyte polyploid DNA content on day 8, megakaryocyte concentration on days 9 through 12 (2 1/2 to 3x normal), and platelets on days 12 through 15 (2x normal). Platelet levels are thought to be important in the feedback regulation of megakaryocytes; however, only polyploid DNA content distributions showed a close inverse relationship to platelet counts during both the recovery and rebound thrombocytosis phases after 5-FU. In contrast, megakaryocyte size peaked before platelet recovery commenced, while megakaryocyte concentration increased in parallel with platelets from 7.5 to 10 days post 5-FU and continued to be maintained at 2 to 3 times normal through day 13, despite platelet levels that were more than twice normal. Both megakaryocyte size and polyploid DNA content distributions shifted toward lower values in response to the rebound thrombocytosis (DNA content on day 10 and size on days 12 and 13). Splenectomy did not substantially alter the pattern of post 5-FU rebound thrombocytosis or megakaryocyte response from that seen in intact mice, indicating that splenic megakaryocytes are not responsible for the prolonged thrombocytosis seen after this drug. In summary, the prolonged thrombocytosis after 5-FU administration results from failure to down-regulate the number of precursors entering the differentiating megakaryocyte compartment. These data indicate that megakaryocyte size and DNA content are responsive to different feedback controls than megakaryocyte concentration in this model system.

Animals↗
PubMed1998

Ovarian carcinoma associated thrombocytosis. Correlation with prognostic factors and with survival.

OBJECTIVE: To assess the prevalence of thrombocytosis (platelets > or = 400,000 microliters) in ovarian cancer of epithelial origin as compared to benign controls consisting of benign ovarian cysts of epithelial origin and to correlate it with prognostic factors of ovarian cancer and survival. METHOD: Hospital records of 82 consecutive patients with ovarian carcinoma, 12 with low malignant potential tumors and 70 with invasive carcinoma, and of 32 patients with benign cysts of epithelial origin were reviewed. The clinical data and preoperative platelet counts were recorded. RESULTS: The prevalence of thrombocytosis in invasive ovarian carcinoma of epithelial origin was significantly higher than in benign controls (24.3% vs 2.9%; p = 0.006). No statistically significant correlation was found between thrombocytosis with age, grade and residual disease. A statistically non-significant excess of thrombocytosis was found among patients with advanced disease, but the survival of patients with thrombocytosis was significantly less favorable (p = 0.04). CONCLUSIONS: Thrombocytosis is significantly more prevalent in ovarian cancer patients than in benign controls and has a statistically significant correlation with poorer survival. The prevalence of thrombocytosis in ovarian carcinoma and its significance in various studies is inconsistent and should be elucidated in large prospective studies.

Adolescent↗
PubMed1990

Thrombocytosis in young people: evaluation of 57 cases diagnosed before the age of 40.

Over the past 13 years 57 cases of primary thrombocytosis in young people have been studied. Only patients with a platelet count over 500 x 10(9)/liter and a follow-up longer than 2 years were considered. Thrombocytosis in young people represents approximately 25% of total cases referred to our department during this period. The most common causes are essential thrombocythemia (20 cases) and secondary thrombocytosis (22 cases). The highest platelet counts are found in essential thrombocythemia patients. Most of our patients were discovered by a fortuitous hematological examination. In contrast, 5 out of the polycythemic patients were recognized after a thrombosis. The same was true for 2 out of 20 essential thrombocythemia subjects. Four subjects (2 essential thrombocythemia and 2 secondary thrombocytosis) were diagnosed after hemorrhages. The overall survival was very good except for leukemic patients and thrombocytosis secondary to neoplasms. Vascular complications after diagnosis were scarce: 2 polycythemia vera patients showed bleedings during antiaggregating therapy. None of our patients developed epithelial cancer, malignant lymphoma or myelofibrosis. Vascular traumata seem more frequent in polycythemia vera regardless of age. Therefore, it seems useful to treat polycythemic patients, while no therapy seems to be indicated in other forms of thrombocytosis.

Adult↗
PubMed2002

Poor prognosis associated with thrombocytosis in patients with gastric cancer.

BACKGROUND: Thrombocytosis is commonly associated with malignant disease and has recently been suggested to be a poor prognostic indicator in patients with lung cancer and gynecological cancers. The prevalence of thrombocytosis in patients with gastric cancer was reviewed, and its association with poor prognosis was investigated. METHODS: Platelet count (PLT) and hemoglobin concentrations (Hb) were reviewed in 369 consecutive patients with histologically verified gastric cancer from 1994 to 2000. Differences between categories were analyzed with analysis of variance, and survival was compared by using the log-rank test on the Kaplan-Meier life table. Multivariate Cox regression analysis was used to evaluate whether thrombocytosis is an independent prognostic marker. RESULTS: Thrombocytosis was found in 42 patients, and anemia was found in 200 patients. PLT was negatively correlated with Hb. Mean PLT was significantly increased in patients with noncurative operations. There was a positive correlation between the depth of tumor invasion and PLT. One- and 3-year survival expectancies in patients with or without thrombocytosis were 52.4% and 23.4% and 85.7% and 72.9%, respectively. PLT was identified as an independent prognostic factor after lymph node metastasis and depth of tumor invasion. CONCLUSIONS: Thrombocytosis is an independent prognostic indicator of survival in patients with gastric cancer.

Adult↗
PubMed1998

Thrombopoietin serum concentration in patients with reactive and myeloproliferative thrombocytosis.

We wished to test whether thrombopoietin (TPO) is entirely regulated by receptor binding or if other factors may play a role in the mechanism of TPO regulation. Therefore, we analyzed the TPO serum levels in 43 patients with reactive (secondary) thrombocytosis and in 37 with myeloproliferative thrombocytosis. Thrombocytosis was defined as a platelet level greater than 440 x 10(9)/l. Forty-two patients (98%) with reactive thrombocytosis had high concentrations of IL-6 correlating with elevated C-reactive protein levels. Twenty-three patients (53%) in this group had TPO serum concentrations of more than 300 pg/ml (normal: below 300 pg/ml). Only nine patients (24%) with myeloproliferative thrombocytosis had TPO serum levels above normal range, whereas 28 patients (76%) had normal levels of TPO. No correlation between the TPO serum levels and the concentrations of IL-6 or EPO was established. The other investigated thrombopoietic cytokines (IL-3, IL-11, GM-CSF) were unmeasurable; therefore, a correlation could not be assessed. We conclude that TPO concentrations are not strictly inversely related to platelet count. TPO serum levels are elevated especially in a considerable percentage of patients with reactive thrombocytosis, arguing for the existence of additional mechanisms of TPO regulation.

Adolescent↗
PubMed2002

Thrombocytosis is associated with a significant increase in the cancer specific death rate after radical nephrectomy.

PURPOSE: We have previously reported that patients with advanced renal cell carcinoma and a normal platelet count of 400,000/mm. have a 64% increase in life expectancy compared with those with thrombocytosis. We determined whether thrombocytosis was predictive of death from renal cell carcinoma after radical nephrectomy was performed with curative intent for early stage disease. MATERIALS AND METHODS: We reviewed the records of 204 patients with renal cell carcinoma who underwent radical nephrectomy with curative intent between June 1993 and January 2000 at Emory University Hospital. Survival, pathological grade and stage were recorded from the Emory Winship Cancer Institute tumor registry. Platelet counts were recorded and any patient with at least 1 platelet count of greater than 400,000/mm. was classified with thrombocytosis. Those with a platelet count of 400,000/mm. were classified with a normal platelet count. RESULTS: There were 26 patients with thrombocytosis and 178 patients with persistently normal platelet counts. The overall and cancer specific death rate in the 26 patients with thrombocytosis was 50% and 42%, respectively. The overall mean time between nephrectomy and death was 12.1 months in this group. The overall and cancer specific death rate in the 178 patients with a normal platelet count was 15.2% and 7.3%, respectively. Mean time to death was 22.6 months in this group. Differences in the overall and cancer specific death rates were highly statistically significant as well as clinically significant. These differences remained significant after controlling for grade, stage and histological type of cancer. CONCLUSIONS: This study documents the association of thrombocytosis with decreased survival in patients with renal cell carcinoma. In those who undergo nephrectomy for early stage renal cell carcinoma with a perioperative platelet count of greater than 400,000/mm. the cancer specific death rate from renal cell carcinoma is greater than 5 times the rate in patients with a persistently normal platelet counts after radical nephrectomy. The platelet count appears to be a new and powerful independent prognosticator in patients with renal cell carcinoma who undergo radical nephrectomy for presumed localized disease.

Aged↗
PubMed2000

Use of a platelet filter test in patients with thrombocytosis.

In the differential diagnosis of primary and secondary thrombocytosis platelet function tests may play an important role. We examined the applicability of a platelet filter test (shear-dependent platelet aggregation) as a tool, to differentiate primary thrombocytosis (cases with myeloproliferative disorders) from secondary (reactive) thrombocytosis. The test was carried out in 53 patients suffering from myeloproliferative disorders associated with primary thrombocytosis and in 21 patients with other diseases complicated by secondary thrombocytosis. Using citrate as anticoagulant, the sensitivity of the O'Brien's test proved to be 77.1%, and its specificity 94.4%. Using heparin as anticoagulant the sensitivity and specificity of the test were found to be also reliably high. Based on these studies we suggest the use of the O'Brien's filterometer as a screening test in the differential diagnosis in patients with elevated platelet count. In the case of normal results, the causes of reactive thrombocytosis should be clarified first, while with abnormal results, haematological examination of the patients should be performed.

Adenosine Diphosphate↗
PubMed1992

Thrombocytosis and thrombocytopenia in childhood bacterial meningitis.

To assess factors affecting the development of reactive thrombocytosis during bacterial meningitis, thrombocyte counts of 311 children with cerebrospinal fluid culture-positive bacterial meningitis were followed during hospitalization. Thrombocytosis (platelet counts greater than 500 x 10(9)/liter) was seen in 49% of the patients after the first week of treatment. Thrombocyte counts were higher in infants and in patients with long duration of illness before admission. Subdural effusion and cephalosporin therapy were associated with more pronounced thrombocytosis We found no relation between thrombocytosis and neurologic complications, but the patients who died developed thrombocytopenia instead of thrombocytosis. The difference between the thrombocyte curves of the surviving and dying patients might be utilized in predicting the final outcome in the severest cases of bacterial meningitis. We speculate that inflammatory cytokines, especially interleukin 1-beta, induce reactive thrombocytosis in bacterial meningitis.

Adolescent↗
PubMed1993

Drug-induced thrombocytosis.

Thrombocytosis is generally defined as platelet counts greater than 400,000/mm3. Thrombocytosis can be either primary or secondary. Adrenalin was one of the first drugs noticed to cause platelet elevations, probably due to demargination of platelets in the pulmonary vasculature. Vinca alkaloids have the most convincing data to show that they can induce thrombocytosis through their thrombocyte-stimulating properties. Miconazole has been implicated in causing thrombocytosis and has a documented case validated by drug rechallenge. Iron, predictably, can cause a transient thrombocytosis. The beta-lactam antibiotic data are very difficult to interpret due to the possibility of an acute-phase reaction in an infected patient being the cause of the thrombocytosis.

Anti-Bacterial Agents↗