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At least 19 recordsLinked to original sources
PubMed1998

Blood thrombopoietin levels in clonal thrombocytosis and reactive thrombocytosis.

BACKGROUND: Although the distinction between clonal and reactive thrombocytosis is clinically relevant because clonal thrombocytosis has more thrombohemorragic complications, the differential diagnosis of these two entities can be difficult. Methods such as the detection of unstimulated erythroid or megakaryocyte colony growth are not readily available. Therefore, we measured blood thrombopoietin levels to determine whether these levels can be used to distinguish the two conditions. PATIENTS AND METHODS: Thrombopoietin levels were measured in 73 patients with thrombocytosis (platelet count > 500,000/microL), including 39 patients with clonal thrombocytosis (20 patients with essential thrombocythemia, 15 with agnogenic myeloid metaplasia, 1 patient with polycythemia vera, and 3 with undefined myeloproliferative disorders) and 34 patients with reactive thrombocytosis (17 with malignant tumors, 11 with inflammatory diseases, 4 with sickle cell disease, and 2 with iron deficiency anemia). Seventeen normal volunteers were used as controls. RESULTS: Thrombopoietin levels were significantly higher (P < 0.05) in patients with clonal thrombocytosis (mean +/- SD of 555 +/- 585 pg/mL), including the subgroup with essential thrombocythemia (505 +/- 459 pg/mL), than in patients with reactive thrombocytosis (290 +/- 133 pg/mL) who had similar levels as controls (201 +/- 112 pg/mL). Thrombopoietin levels in patients with clonal thrombocytosis, including essential thrombocythemia, were not correlated with platelet counts. CONCLUSIONS: Thrombopoietin levels may be helpful in distinguishing between clonal thrombocytosis and reactive thrombocytosis. Thrombopoietin is probably responsible for the elevated platelet counts in clonal thrombocytosis including essential thrombocythemia, but not in reactive thrombocytosis. High thrombopoietin levels in patients with clonal thrombocytosis cannot be explained solely by platelet megakaryocyte mass.

Adult↗
PubMed1991

Which tests are most useful in distinguishing between reactive thrombocytosis and the thrombocytosis of myeloproliferative disease?

In an attempt to distinguish between thrombocytosis in myeloproliferative disease (MPD) and reactive thrombocytosis (RT) the following aspects of platelet structure and function were evaluated: platelet size, platelet aggregation and adhesion, dense granule and alpha granule components. In addition plasma fibrinogen and von Willebrand factor antigen (vWFag) were measured. In all parameters measured there was a significant difference between normals and both categories of thrombocytosis, however there was considerable overlap between MPD and RT. Plasma fibrinogen emerged as the best single test to discriminate between MPD and RT, levels of less than 5.0 g/l indicating MPD and greater than 5.0 g/l indicating RT.

Antigens↗
PubMed1994

Plasma interleukin-6 and C-reactive protein levels in reactive versus clonal thrombocytosis.

PURPOSE: Evaluate the discriminatory value of plasma interleukin-6 or C-reactive protein levels in clonal thrombocytosis compared with those in reactive thrombocytosis. PATIENTS AND METHODS: A comparative analysis of quantitatively measured laboratory values in a prospectively studied group of consecutive patients. The setting was a tertiary referral center consisting of two hospitals and an outpatient clinic. Plasma interleukin-6 and C-reactive protein levels were measured in 91 consecutive patients with thrombocytosis (platelet count > or = 600 x 10(9)/L). The cause of thrombocytosis was determined by reviewing the medical histories and follow-up data without knowledge of the corresponding laboratory values. Sixty-four patients had reactive thrombocytosis, 20 had clonal thrombocytosis, and 7 had clonal thrombocytosis plus reactive thrombocytosis. Plasma interleukin-6 was measured by an enzyme-linked immunosorbent assay, and C-reactive protein was measured with rate immunonephelometry. RESULTS: Interleukin-6 levels were undetectable in all the patients with clonal thrombocytosis, whereas they were increased in 60% of the patients with reactive thrombocytosis or clonal thrombocytosis plus reactive thrombocytosis. There was a correlation between interleukin-6 and C-reactive protein levels (r = .6), and the median and range values of both levels differed significantly between the clonal thrombocytosis group and the other two groups (P < 0.0001). In 81% of the patients with reactive thrombocytosis, levels of either interleukin-6 or C-reactive protein were elevated. There was no correlation between interleukin-6 and C-reactive protein levels and the platelet count. CONCLUSIONS: An elevated interleukin-6 level is rare in uncomplicated clonal thrombocytosis and suggests reactive thrombocytosis. However, an isolated normal value has little discriminatory value. Measurement of C-reactive protein level may be used as a less expensive surrogate for measurement of interleukin-6. Repeatedly low levels of both interleukin-6 and C-reactive protein are most consistent with clonal thrombocytosis.

Aged↗
PubMed1995

[C-reactive protein in differential diagnosis of primary thrombocytosis].

BACKGROUND: The most potent stimulator for the hepatic synthesis of C-reactive protein is the interleukin-6. Also interleukin-6 is endowed with thrombopoietic activity, and its seric levels increases in most of secondary thrombocytosis whereas they remain normal in chronic myeloproliferative diseases or primary thrombocytosis. The aims of the study were verify the ability of quantitation of serum C-reactive protein in the differential diagnosis of primary thrombocytosis. METHODS: Serum samples from 89 patients with thrombocytosis (> 400 x 10(9)/1) and 54 normal controls were assayed for C-reactive protein. Patients with thrombocytosis were classified in primary thrombocytosis with 27 patients (chronic myeloproliferative disease with thrombocytosis) and secondary thrombocytosis (62 cases). RESULTS: The mean C-reactive protein serum levels observed in the 27 patients with primary thrombocytosis were 13 +/- 10 mg/l, superior to normal controls (7 +/- 5 mg/l; p < 0.01). In the secondary thrombocytosis group, C-reactive protein serum levels reached a mean value of 59 +/- 34 mg/l, clearly superior to control group and the primary thrombocytosis group (p < 0.0001). No patients in primary thrombocytosis group reached a C-reactive protein value > 40 mg/l, versus 65% of patients in secondary thrombocytosis group. A normal value occurred in 67% cases of primary thrombocytosis group, but also in 17% cases of secondary thrombocytosis group. CONCLUSIONS: Quantitation of C-reactive protein could thus prove useful in the differential diagnosis between primary and secondary thrombocytosis.

C-Reactive Protein↗
PubMed1998

Correlation of thrombosis with increased platelet turnover in thrombocytosis.

There are no readily applicable methods to routinely assess thrombosis risk and treatment response in thrombocytosis. Reticulated platelets (RP) define the most recently released platelets in the circulation, and the RP% has been shown to estimate platelet turnover in thrombocytopenic states. We examined whether increased RP values were associated with thrombotic complications in thrombocytosis. Platelet count, RP%, and absolute RP count were measured at presentation in 83 patients with chronic or transient thrombocytosis, 46 patients with deep vein (DVT) or arterial (ART) thrombosis and normal platelet counts, and 83 healthy controls with normal platelet counts. Chronic thrombocytosis patients presenting with thrombosis (n = 14) had significantly higher RP% (14.7% +/- 10. 1%, mean +/- SD) than asymptomatic chronic thrombocytosis patients (n = 23, RP% = 3.4% +/- 1.8%), healthy controls (3.4% +/- 1.3%), DVT patients (n = 21, 3.8% +/- 2.1%), or ART patients (n = 25, 4.5% +/- 4.1%, P < .05 for all comparisons). Chronic thrombocytosis patients with thrombosis also had significantly higher absolute RP counts than asymptomatic chronic thrombocytosis patients (98 +/- 64 x 10(9)/L [range, 54 to 249 x 10(9)/L] v 30 +/- 13 x 10(9)/L [range, 11 to 51 x 10(9)/L]; P = .0004), whereas healthy controls, DVT, and ART patients had similarly low absolute RP counts (6 +/- 6 x 10(9)/L, 9 +/- 7 x 10(9)/L, and 11 +/- 7 x 10(9)/L, respectively; P > .49). The RP% and absolute RP counts remained significantly higher in chronic thrombocytosis patients with thrombosis when patients were further subdivided into primary myeloproliferative disorders versus secondary thrombocytosis. Similarly elevated RP percentages and absolute counts were also noted in transient thrombocytosis patients with thrombosis (n = 6, 11.5% +/- 4.4% and 90 +/- 46 x 10(9)/L, respectively) when compared with asymptomatic transient thrombocytosis patients (n = 40, 4.5% +/- 2.7% and 35 +/- 16 x 10(9)/L, respectively) and to all control groups (P < .05 for all comparisons). In addition, 7 of 8 thrombocytosis patients who were studied before developing symptoms of thrombosis had elevated absolute RP counts compared with only 1 of 63 thrombocytosis patients who remained asymptomatic. Follow-up studies in seven chronic thrombocytosis patients showed that successful aspirin treatment of symptomatic recurrent thrombosis significantly reduced the RP% from 17.1% +/- 10.9% before therapy to 4.8% +/- 2.0% after therapy; absolute RP counts decreased from 102 +/- 67 x 10(9)/L to 26 +/- 10 x 10(9)/L (P < .01 for both). We conclude that thrombosis in the setting of an elevated platelet count is associated with increased platelet turnover, which is reversed by aspirin therapy. Measurement of reticulated platelets to assess platelet turnover may be useful in evaluating both treatment response and thrombotic risk in thrombocytosis.

Adolescent↗
PubMed1999

The observation of reactive thrombocytosis in New Zealand white rabbits in response to experimental Pasteurella multocida infection.

Reactive thrombocytosis is an increase in the circulating thrombocyte count secondary to a physiologic process within the body, often an infection. Reactive thrombocytosis is different than primary or essential thrombocytosis which is usually related to myeloproliferative neoplasia. Essential thrombocytosis is most common in adults, whereas reactive thrombocytosis is most frequently observed in children. Reactive thrombocytosis has been occasionally reported in cats, dogs and horses but has not been previously reported in the rabbit. Rabbits were challenged with virulent Pasteurella multocida. Hematologic, clinical, and culture assessments were performed prior to challenge, enabling each animal to serve as its own control. The questions asked were whether reactive thrombocytosis was a consistent phenomena and whether its presence and/or intensity was related to disease severity. All challenged rabbits demonstrated some degree of thrombocytosis in response to the infection, but individual rabbits were varied in their pattern of thrombocytosis. Elevations varied from intense to mild to undulating with durations of 1 to 11 days above 500 x 10(9)/L and 0 to 5 days above 650 x 10(9)/L. Correlation analysis was unable to demonstrate significant association between thrombocytosis, body temperature, leukocyte count, or the granulocyte lymphocyte ratio (all r < 0.2). No significant association between intensity of thrombocytosis and degree or type of pathologic lesions was observed. Thrombocytosis does not appear predictive of disease intensity or outcome. The data indicate that in the rabbit thrombocytosis is a consistent response to infection with P. multocida. Rabbits may serve as a model for the study of reactive thrombocytosis, in humans especially in children infected with Haemophilus sp., which are also a members of the bacterial family Pasteurellaceae.

Animals↗
PubMed1999

Aetiology and clinical significance of thrombocytosis: analysis of 732 patients with an elevated platelet count.

OBJECTIVE: To determine the aetiology and clinical significance of an elevated platelet count (thrombocytosis) in a large cohort of patients. DESIGN: A retrospective review of the medical records was performed on all patients, who had at least one platelet count > or = 500 x 10(9) L-1. SETTING: Departments of Medicine and Surgery, University of Ulm, Germany. SUBJECTS: A total of 732 patients with thrombocytosis. MAIN OUTCOME MEASURES: Classification of thrombocytosis and thromboembolic complications, and evaluation of laboratory parameters distinguishing between primary and secondary thrombocytosis. RESULTS: Of the total of 732 patients, 89 (12.3%) had primary and 643 (87.7%) had secondary thrombocytosis. Essential thrombocythaemia was observed in 40 of 89 patients (45%) with primary thrombocytosis. The most frequent causes of secondary thrombocytosis were tissue damage (42%), infection (24%), malignancy (13%) and chronic inflammation (10%). Primary thrombocytosis was significantly associated with a higher platelet count and an increased incidence of both arterial and venous thromboembolic complications. In secondary thrombocytosis, thromboembolic events were restricted to the venous system and occurred only in the presence of other risk factors. Mean values of leucocyte count, haematocrit, erythrocyte sedimentation rate, fibrinogen, serum potassium and lactate dehydrogenase were significantly different in primary and secondary thrombocytosis. CONCLUSIONS: The finding of an elevated platelet count on routine blood examination has diagnostic, prognostic and therapeutic implications. It is of clinical importance to distinguish between primary and secondary thrombocytosis, as thrombotic complications occur more frequently in primary thrombocytosis. Unless additional risk factors are present, secondary thrombocytosis is not associated with a significant risk for thromboembolic events.

Adolescent↗
PubMed2002

Reactive thrombocytosis alone does not affect the patency of microvascular anastomosis in the splenectomy rat.

Vascular thrombosis is a harbinger of failure in microsurgery. However, there is still controversy regarding the correlation of the complications of thrombocytosis and thrombosis. Some evidence indicates that patients with elevated platelet counts tend to have a higher flap failure rate, and surgeons usually hesitate to operate on patients with thrombocytosis. Nevertheless, the authors have experienced successful free tissue transfer in seven patients with thrombocytosis resulting from traumatic splenectomy or multiple trauma. On the basis of clinical observation, the authors investigated whether reactive thrombocytosis contributes to the patency of a microvascular anastomosis. In a rodent splenectomy-induced thrombocytosis model (n = 40), stable reactive thrombocytosis occurred after postoperative days 5 to 10, with the peak on postoperative day 7. Femoral artery division and reanastomosis was performed in rats with or without splenectomy-induced thrombocytosis, and vascular patency was assessed. Platelet counts and platelet activation were studied in correlation to microvascular patency. Platelet activation as demonstrated by CD62P expression on platelets was not significantly different between rats with and without thrombocytosis (6.41 +/- 0.95 percent versus 4.51 +/- 0.55 percent, respectively; p = 0.089). As immature platelets were not increased (2.86 +/- 0.33 percent versus 1.99 +/- 0.32 percent, p = 0.074), it seems that the splenectomy-induced thrombocytosis is the result of redistribution of platelets instead of an increase in bone marrow production. There were no significant differences in the patency rates or perfusion units of femoral artery after arterial anastomosis between rats with and without thrombocytosis (90 percent and 95 percent, respectively; p = 0.561). In conclusion, this study demonstrates that microvascular anastomosis can be performed safely in patients with reactive thrombocytosis without platelet activation.

Anastomosis, Surgical↗
PubMed1996

Prognostic significance of thrombocytosis in patients with primary lung cancer.

In patients with malignancies, thrombocytosis has previously been related to disease stage, histological type, and survival. In the present study, the prevalence of thrombocytosis and the prognostic information provided by platelet counts were analysed in a large cohort of patients with primary lung cancer. At the time of diagnosis, pretreatment platelet counts were retrospectively recorded in 1,115 consecutive patients with histologically proven primary lung cancer. All patients were reviewed regarding histological type, tumour, node, metastasis (TNM) classification stage and survival. The prevalence of thrombocytosis in patients with lung cancer was compared with that in a series of 550 consecutive out-patients with benign lung disorders. In 269 surgically resected patients, postoperative platelet counts were recorded 1-3 months after resection of the tumour. In the follow-up period, thromboembolic episodes diagnosed either clinically or at autopsy were recorded. The overall prevalence of thrombocytosis (> 400 x 10(9) platelets.L-1) in the patients with lung cancer was 32%. The frequency of thrombocytosis was significantly higher compared with the control subjects (32 vs 6%; p < 0.0001). Platelet counts differed significantly among subgroups defined by the TNM classification, with the proportion of patients with > 400 x 10(9) platelets.L-1 greatest in the more advanced TNM stages (stage I and II 23% vs stage III and IV 37%; p < 0.0001). Patients with thrombocytosis had a significantly poorer survival than patients with normal platelet counts (p < 0.0001). In a multivariate survival analysis (Cox model), thrombocytosis continued to correlate strongly with poor survival even when adjusted for histological type, sex, age, and TNM stage (p < 0.001). In surgically resected patients, the frequency of preoperative and postoperative thrombocytosis differed significantly (23.0 vs 8.9%; p < 0.0001). Survival rate was significantly reduced in patients with preoperative thrombocytosis (p = 0.005). Thrombocytosis was not associated with an increased incidence of thromboembolism. In conclusion, thrombocytosis is an independent prognostic factor of survival in patients with primary lung cancer. We suggest that platelet counts should be included in future multivariate analyses of survival in patients with lung cancer.

Adult↗
PubMed1994

Thrombocytosis in surgically treated stage IB squamous cell cervical carcinoma (A Gynecologic Oncology Group study).

Thrombocytosis has previously been shown to be an unfavorable prognostic factor in cervical cancer patients treated with irradiation. We evaluated the significance of thrombocytosis (platelet count > 400 x 10(9)/liter in 623 surgically treated patients with stage IB squamous cell carcinoma of the cervix. These patients had no gross evidence of extrauterine disease at the time of exploration, and none had metastasis to the para-aortic nodes. Fifty-nine (9.5%) of these 623 patients had thrombocytosis. The 5-year survival for patients with thrombocytosis was 82% compared to 83.5% for patients with normal platelet count (P = 0.4). Pelvic node metastasis was present in 13 (22%) of 59 patients with thrombocytosis, and 77 (13.7%) of 564 patients with normal platelet count (P = 0.1). There was a significant correlation between tumor size and platelet count. Patients with thrombocytosis had a mean tumor size of 27.9 mm, while it was 20.4 mm in patients without thrombocytosis (P = 0.002). Other factors found to be associated with thrombocytosis in this population were elevated white blood cell (WBC) count (P = 0.009) and history of chronic obstructive pulmonary disease (COPD) (P = 0.02). In a multivariate analysis for thrombocytosis adjusted for COPD, WBC count, and tumor size, tumor size continued to be statistically significant (P = 0.01). These data suggest that thrombocytosis is a marker of tumor burden and not an independent prognostic factor for progression-free interval or survival.

Adult↗
PubMed2000

The significance of thrombocytosis in patients with locally advanced cervical carcinoma: a Gynecologic Oncology Group study.

OBJECTIVE: The aim of this study was to determine the incidence of thrombocytosis and its possible impact on survival probability among women with locally advanced cervical carcinoma. METHODS: The database of 294 patients with Stages IIB-IVA cervical carcinoma without periaortic node metastasis who were treated with standardized radiation therapy and concurrent hydroxyurea or misonidazole was analyzed. Pretreatment platelet counts were available for 291 patients who are the subject of this study. RESULTS: Thrombocytosis (platelet count >400 x 10(9)/liter) was present in 86 (29.6%) of the 291 patients. A multivariate Cox proportional hazards model showed that patients without extrapelvic disease and with thrombocytosis had a 55% greater chance of dying than those without thrombocytosis (relative risk = 1.55, 95% confidence interval 1.08-2.21). Patients with thrombocytosis had larger tumors and more frequently had bilateral parametrial involvement, tumor fixation to the sidewall, and positive pelvic lymph nodes than patients without thrombocytosis. Thrombocytosis was not found to be a prognostic factor in patients with positive pelvic nodes. However, in patients with negative pelvic nodes, the presence or absence of thrombocytosis was related to survival. CONCLUSION: Thrombocytosis is a frequent finding among patients with advanced cervical carcinoma and seems to be related to tumor burden. Among patients with locally advanced cervical carcinoma who had negative pelvic nodes, those with thrombocytosis had a poorer survival.

Adult↗
PubMed2004

The prognostic significance of thrombocytosis in epithelial ovarian carcinoma.

OBJECTIVE: The objective of this study was to determine the incidence of thrombocytosis in epithelial ovarian carcinoma and examine associations with clinico-pathologic features. Thrombocytosis (platelet counts >400 x 10(9)/l) has been identified as a poor prognostic factor in many cancers. Platelet-secreted factors may contribute to metastasis, invasion, and primary tumor growth. METHODS: One hundred eighty-three patients with invasive epithelial ovarian or primary peritoneal carcinomas were identified between January 1996 and December 2000. Records were retrospectively reviewed and data analyzed using chi(2), Student's t test, and Cox proportional hazards model; survival was analyzed by the method of Kaplan and Meier. RESULTS: Forty-one of 183 (22.4%) patients had thrombocytosis at primary diagnosis. Patients with preoperative thrombocytosis were found to have greater elevations of CA-125 (P = 0.026), more advanced stage disease (P = 0.016), higher grade tumors (P = 0.010), more frequent lymph node metastases (P = 0.018), and greater volume of ascites (P < 0.0001). One hundred sixty of 183 (87.4%) patients achieved optimal cytoreduction; patients with thrombocytosis demonstrated a greater likelihood of suboptimal resection (residual disease >1 cm; 19/41 vs. 4/142 in patients without thrombocytosis, P < 0.0001). Patients with thrombocytosis had a shorter disease-free interval (12 vs. 34 months, P < 0.0001) and overall survival (28 vs. 79 months, P < 0.0001). On multivariate analysis, thrombocytosis retained significance as a poor prognostic indicator in patients with stage III and IVA disease (P = 0.04). CONCLUSIONS: Thrombocytosis is a frequent preoperative finding in ovarian and peritoneal carcinomas and may be a marker of aggressive tumor biology.

Disease-Free Survival↗
PubMed2002

Circulating thrombopoietin in clonal versus reactive thrombocytosis.

INTRODUCTION: The aim of this study is to assess circulating thrombopoietin concentrations in patients with both clonal and reactive thrombocytosis (RT), which are two distinct categories of extreme platelet production circumstances. Investigation of the thrombopoietin levels in clonal versus reactive thrombocytosis may help us to understand the interactions of this key regulatory cytokine and the conditions in which abnormally increased platelet formation exist. MATERIALS AND METHODS: Thrombopoietin levels were measured in patients with platelet counts greater than 500 x1 0(3) microl(-1). The study population consisted of 21 patients with RT (13 with iron deficiency anemia, and 8 with rheumatoid arthritis), 24 patients with clonal thrombocytosis (six with essential thrombocytosis, three with myelofibrosis, eight with chronic myelogenous leukemia, and seven with polycythemia vera (PV)) and 16 healthy subjects were used as controls. RESULTS: The median plasma thrombopoietin concentration was 100.5 pg ml(-1) in patients with RT, 467 pg ml(-1) in patients with clonal thrombocytosis and 62.65 pg ml(-1) in the control group. The thrombopoietin concentration was found to be higher in the patients with primary thrombocytosis when compared to the control group (p=0.001), as well as in patients with RT (p=0.002). However, there was no statistically significant difference between the patients with RT and the control group (p=0.14). There was no correlation between thrombopoietin levels and the platelet counts in patients with clonal thrombocytosis, including essential thrombocythemia (ET). CONCLUSIION: Increased levels of thrombopoietin were found in patients with clonal thrombocytosis versus patients with RT and control subjects as well. Defective clearance of thrombopoietin by megakaryocytes and platelets due to a reduced number of thrombopoietin receptors may be the causative mechanism behind this. These results indicate that plasma thrombopoietin levels may be helpful in distinguishing between clonal and reactive thrombocytosis.

Adult↗
PubMed1986

Platelet volume analysis for differential diagnosis of thrombocytosis.

The results of the Coulter counter S plus II platelet volume analysis were studied in 100 patients with reactive thrombocytosis (platelet count greater than 500 X 10(9)/l), in 30 patients with myeloproliferative thrombocytosis, and in 32 patients with chronic myeloproliferative disease and a platelet count less than 500 X 10(9)/l. Patients with reactive thrombocytosis had considerably lower mean platelet volumes than those with myeloproliferative thrombocytosis, or normal subjects. The opposite was true for the platelet distribution width. This index for platelet heterogeneity was normal in reactive, but increased in myeloproliferative thrombocytosis. There were no differences in mean platelet volume or platelet distribution width between patients with myeloproliferative disease and a high or normal platelet count. The increased platelet heterogeneity in myeloproliferative disease was caused by an increase of both small and large platelets. The platelet distribution width seemed to be the best variable for the differential diagnosis of thrombocytosis. A platelet distribution width greater than 17 was found in 26 of the 30 patients with myeloproliferative thrombocytosis but in only five of the 100 patients with reactive thrombocytosis. A normal platelet distribution width in a patient with a high platelet count strongly suggests reactive thrombocytosis.

Blood Platelets↗
PubMed1994

Thrombocytosis. Etiologic analysis of 663 patients.

Six hundred sixty-three children aged 1 to 16 years with thrombocytosis (defined as a platelet count of more than 500 x 10(9)/L) seen in a university hospital over a 1-year period were studied prospectively for etiology. The causes of thrombocytosis were infection (30.6%), hemolytic anemia (19.3%), tissue damage (15.2%), rebound thrombocytosis (14.8%), chronic inflammation (4.1%), renal disorders (4.1%), and malignancy (2%). Thrombocytosis associated with multiple, simultaneous causative factors was seen in 3.3% of cases. Among all patients with infections, osteomyelitis and septic arthritis were associated with higher platelet counts than other infections (P < .0001). Thrombocytosis secondary to infections was significantly more common in children under 5 years of age, whereas chronic inflammation, malignancy, and renal disorders were more common causes of thrombocytosis in children over 5 years of age. Thrombocytosis of 1 million or more platelets was seen in 13 (2%) children. No thrombocytosis-related complications were seen in any children, and none required any specific treatment. Thrombocytosis is a frequent finding in children. It is due to a variety of etiologic factors and is of little clinical discriminatory value. It is often due to an acute-phase phenomenon in response to infection, tissue damage, blood loss, or anemia, and is rarely due to malignancy.

Acute-Phase Reaction↗
PubMedDate not supplied

Thrombocytosis in children at one medical center of southern Taiwan.

Thrombocytosis in children is common, but usually without symptoms. The causes of thrombocytosis in children are considered to be mostly due to infection, trauma, surgery, blood disease, prematurity, renal disease and chronic inflammation. To evaluate the incidence and etiology of thrombocytosis of the hospitalized patients, patients who were admitted to the Pediatric Department of Kaohsiung Medical College Hospital (KMCH) from October 1996 to November 1997 were studied. There were 2910 cases studied and 220 cases (127 male and 93 female) had thrombocytosis (> or = 500 x 10(9)/L) with a rate of 7.6%. The causes of thrombocytosis are infections (49.5%), Kawasaki disease (6.4%), postsplenectomy (7.8%), blood diseases (3.7%), malignancies (3.2%), renal disorders (3.2%), prematurity (3.2%), tissue damage (4.5%), chronic inflammation (1.8%), recovery from marrow suppression (1.3%), immunologic disturbances (2.2%), essential thrombocythemia (0.5%), and miscellaneous factors (3.7%). Thrombocytosis associated with multiple, simultaneous causative factors was found in 9.0% of these cases. Thrombocytosis secondary to infectious diseases or Kawasaki disease was significantly more common in children under 2 years old. The most commonly associated infectious disease was respiratory tract infection (61.1%). There were 29 children (13.2%) presenting a platelet count of more than 800,000/mm3. However, no thrombotic complications were seen in any of the children. By far, the major cause of thrombocytosis in our cases was reactive in character. Most of the thrombocytosis cases were due to infections, inflammatory diseases, or Kawasaki disease.

Adolescent↗