Clinicohematological study of thrombocytosis

Pathophysiology, classification, and complications of common asymptomatic thrombocytosis in newborn infants

We frequently encounter newborn infants with thrombocytosis in the neonatal intensive care unit. However, neonatal thrombocytosis is not yet fully understood. Thrombocytosis is more frequently identified in newborns and young infants, notably more often in those younger than 2 years than in older children or adults. The production of megakaryocytes (megakaryopoiesis) and platelets (thrombopoiesis) is mainly regulated by thrombopoietin (TPO). Increased TPO levels during infection or inflammation can stimulate megakaryopoiesis, resulting in thrombopoiesis. TPO concentrations are higher in newborn infants than in adults. Levels increase after birth, peak on the second day after birth, and start decreasing at 1 month of age. Initial platelet counts at birth increase with gestational age. Thus, preterm infants have lower initial platelet counts at birth than late-preterm or term infants. Postnatal thrombocytosis is more frequently observed in preterm infants than in term infants. A high TPO concentration and low TPO receptor expression on platelets leading to elevated plasma-free TPO, increased sensitivity of megakaryocyte precursor cells to TPO, a decreased red blood cell count, and immaturity of platelet regulation are speculated to induce thrombocytosis in preterm infants. Thrombocytosis in newborn infants is considered a reactive process (secondary thrombocytosis) following infection, acute/chronic inflammation, or anemia. Thrombocytosis in newborn infants is benign, resolves spontaneously, and, unlike in adults, is rarely associated with hemorrhagic and thromboembolic complications.

Reactive Thrombocytosis after Splenectomy in Hereditary Spherocytosis: Case Report and Literature Review

Reactive thrombocytosis after splenectomy is a feared cause of thrombosis throughout the arterial and venous system. There are many causes of splenomegaly, ranging from cirrhosis to lymphoma to hereditary spherocytosis. In this report, we will discuss a case of reactive thrombocytosis after splenectomy in a patient with hereditary spherocytosis. Splenomegaly is a relatively common finding in HD patients, causing extravascular haemolysis and thus leading to haemolytic anaemia. Splenectomy is usually considered when patients start to manifest severe symptoms such as abdominal pain, jaundice or worsening liver function tests. Our patient was a good surgical candidate and successfully underwent splenectomy but afterwards developed arterial and venous thrombosis due to reactive thrombocytosis. An extensive hypercoagulable work-up was unremarkable. The patient was started on hydroxyurea and anticoagulation with eventual improvement of platelet levels.

LEARNING POINTS

Reactive thrombocytosis can be a significant complication after splenectomy and can range from mild (500,000-700,000/mm³), to moderate (700,000-900,000/mm³), severe (>900,000/mm³) and very severe thrombocytosis (>1,000,000/mm³).The use of low-dose hydroxyurea in patients with very severe thrombocytosis can reduce the platelet count to safe levels, and thus, the risk of developing thrombosis.

Relationship between RNASE1, ANG and RNASE6 gene polymorphism and the values of blood indices in suckling piglets

The relationship between PcR-restriction fragment length polymorphism in RNASE1 (296 A/G), ANG (149 G/T) and RNASE6 (389 C/T) genes and the values of haematological and biochemical blood indices was analysed in crossbred suckling piglets (n = 473), aged 21 ± 3 days (younger, n = 274) and 35 ± 3 days (older, n = 199), descending from Polish Large White × Polish Landrace sows and Duroc × Pietrain boars. The observed distribution of all genotypes was consistent with the Hardy-Weinberg equilibrium. Anaemia was more common in younger piglets with RNASE1 GA genotype but in the blood of older GA piglets a higher count and percentage of granulocytes were noted. This could be related to the destruction of erythrocytes in younger piglets and enhanced host defence in older ones. ANG gene polymorphism was associated with the severity of iron deficiency in younger piglets. This is supposed to be linked with the different ability to protect immune cells against suppression and degradation during iron deficiency. in older piglets, this mutation differentiated the reactivity of the immune system. Varying levels of iron status and red blood cell indices in RNASE6 genotypes presumably resulted from the coupling of genes involved in iron metabolism and expressed in an age-dependent manner.

Secondary severe thrombocytosis in a patient who underwent splenectomy due to hereditary spherocytosis and its treatment using hydroxyurea

Thrombocytosis is a frequently seen condition during childhood. While it usually develops secondarily due to reasons such as infection or anemia, it may rarely develop due to clonal causes. Thrombocytosis becomes a life-threatening condition by causing severe complications such as hemorrhage and thrombosis development. Treatment is not recommended in patients who are asymptomatic and with a platelet count below 1,500,000/mm³, however, treatment is required in cases who are symptomatic and with a platelet count above 1,500,000/mm³ in conditions such as primary thrombocytosis. This article present the outcomes of a patient who was treated using low-dose hydroxyurea when he developed severe thrombocytosis after splenectomy.

Thrombocytosis in a male patient with acute promyelocytic leukaemia during all-trans retinoic (ATRA) acid treatment

We present a rather uncommon side effect observed in a 20-year-old man with acute promyelocytic leukemia during treatment with ATRA. He developed a high platelet counts reaching up to 1655×10⁹/L on day 29 of ATRA treatment, and started to recover spontaneously on day 33 of treatment, without any change in ATRA, or adding any cytoreduction therapy. No complications associated with thrombocytosis were observed. IL-6 seems to play an important role in the pathogenesis of the thrombocytosis induced by ATRA. However, it is unclear what are the precipitating factors for this rare phenomenon and whether it is caused by certain predisposing factors that might be related to patient's, disease pathogenesis or other unknown factors.

Thrombocytosis in children: Clinico-hematological profile from a single centre in Eastern India

BACKGROUND AND OBJECTIVE:

Thrombocytosis is not an uncommon finding in hemograms of children with an incidence of 6%–15% among hospitalized children. This study aims to determine the etiology of thrombocytosis and analyze various platelet parameters in children attending our hospital.

MATERIALS AND METHODS:

A prospective observational study was carried out in a tertiary care center in Odisha, in eastern part of India, for 6 months from July 2016 to December 2016. All children of age group 1–14 years of age attending pediatrics and other pediatric super specialty outdoors and/or admitted to indoors and whose complete blood counts (CBC) were done were included in the study. The CBC parameters such as hemoglobin, red blood cell indices, and platelet indices (platelet distribution width [PDW], mean platelet volume [MPV], platelet large cell ratio [P-LCR]) were noted.

RESULTS:

Out of 2500 hemograms done in pediatrics age group, 272 (10.8%) patients showed thrombocytosis. About 99.6% of cases were of secondary thrombocytosis. Only one case of primary thrombocytosis was encountered. The most common cause of secondary thrombocytosis was infection (39.5%) alone followed by iron deficiency anemia (14.1%). With increasing platelet counts, a decrease in MPV, P-LCR, and PDW was noted which was statistically significant (P < 0.05).

CONCLUSION:

Thrombocytosis is not rare (10.8%) in children. Secondary thrombocytosis is common and predominatly attributed to infection.

Extreme Thrombocytosis Presenting in Anti-Neutrophil Cytoplasmic Autoantibodies-Associated Crescentic Glomerulonephritis with Immune Complex Deposits: A Case Report

INTRODUCTION

We describe a female patient with extreme reactive thrombocytosis (RT) in anti-neutrophil cytoplasmic autoantibodies (ANCA)-associated crescentic glomerulonephritis (CGN) with immune complex deposits, which has never been reported before.

CASE PRESENTATION

A female adolescent with symptoms of oliguria and gross hematuresis had serious renal function impairment (crescent formation and immune complex deposits in renal pathology examination with positive serum ANCA) and extreme thrombocytosis. We made a diagnosis of CGN and RT. After treatment with Prednisone, Cyclophosphamide, and plasmapheresis, the symptoms of oliguria and gross hematuresis were relieved remarkably and the serum creatinine and platelet count declined significantly.

CONCLUSIONS

The diagnosis of thrombocytosis is not easy in all cases. The coexistence of ANCA and the immune complex in CGN may cause a severe inflammatory state, leading to extreme RT. The roles that the immune complex and ANCA play on the effect of the platelet count and function in CGN need further research.

Association between secondary thrombocytosis and viral respiratory tract infections in children

Secondary thrombocytosis (ST) is frequently observed in children with a variety of clinical conditions. The leading cause of ST is respiratory tract infection (RTI) in children. Nasopharyngeal aspirate samples were collected and assessed for common respiratory viruses. The relationships between virus infections and secondary thrombocytosis were analyzed retrospectively. The blood platelet count and the presence of respiratory viruses were determined for 3156 RTI patients, and 817 (25.9%) cases with platelet ≥500 × 10(9)/L were considered as the thrombocytosis group. Compared with the normal group, the detection rates of respiratory syncytial virus (RSV) and human rhinovirus (HRV) were significantly higher in the thrombocytosis group (P = 0.017 and 0.042, respectively). HRV single infection was a risk factor associated with thrombocytosis [odds ratio (OR) = 1.560, 95% confidence interval (CI) = 1.108-2.197]. Furthermore, ST was more likely to occur in younger patients who had clinical manifestations of wheezing and dyspnea and who had been diagnosed with bronchiolitis. Furthermore, the course of disease lasted longer in these patients. ST is associated with viral respiratory tract infections, especially RSV and HRV infections. HRV single infection is a risk factor associated with thrombocytosis.

Extreme reactive thrombocytosis in a healthy 6 year-old child

Thrombocytosis is usually found by chance in children. Reactive or secondary thrombocytosis is the more common form, with infectious diseases being the most prevalent cause of it. Regarding the number of platelets there are four degrees of thrombocytosis; in its extreme degree the number of platelets exceeds 1,000,000/mm³. We describe a case of extreme reactive thrombocytosis in a healthy 6-year-old child. He required critical care admission for diagnosis and treatment (maximum number of platelets 7,283,000/mm³). We review the different causes of thrombocytosis in childhood, the differential diagnosis, and the available treatments in case of extreme thrombocytosis.

Clinicohematological study of thrombocytosis in children

Introduction. Primary thrombocytosis is very rare in children; reactive thrombocytosis is frequently observed in children with infections, anemia, and many other causes. Aims and Objectives. To identify the etiology of thrombocytosis in children and to analyze platelet indices (MPV, PDW, and PCT) in children with thrombocytosis. Study Design. A prospective observational study. Material and Methods. A total of 1000 patients with thrombocytosis (platelet > 400 × 10(9)/L) were studied over a period of 2 years. Platelet distribution width (PDW), mean platelet volume (MPV), and plateletcrit (PCT) were noted. Results. Of 1000 patients, 99.8% had secondary thrombocytosis and only two children had primary thrombocytosis (chronic myeloid leukemia and acute myelogenous leukemia, M7). The majority of the children belonged to the age group of 1month to 2 years (39.7%) and male to female ratio was 1.6 : 1. Infection with anemia (48.3%) was the most common cause of secondary thrombocytosis followed by iron deficiency alone (17.2%) and infection alone (16.2%). Respiratory infection (28.3%) was the predominant infectious cause observed. Thrombocytosis was commonly associated with IDA among all causes of anemia and severity of thrombocytosis increased with severity of anemia (P = 0.021). With increasing platelet count, there was a decrease in MPV (<0.001). Platelet count and mean PDW among children with infection and anemia were significantly higher than those among children with infection alone and anemia alone. None were observed to have thromboembolic manifestations. Conclusions. Primary thrombocytosis is extremely rare in children than secondary thrombocytosis. Infections in association with anemia are most commonly associated with reactive thrombocytosis and severity of thrombocytosis increases with severity of anemia.

[Extreme reactive thrombocytosis in a healthy 6 year-old child]

Thrombocytosis is usually a casual finding in children. Reactive or secondary thrombocytosis is the more common form, being the infections diseases the most prevalent cause of it. Regarding the number of platelets there are four degrees of thrombocytosis; in its extreme degree the number of platelets exceeds 1,000,000/mm(3). We describe a case of extreme reactive thrombocytosis in a healthy 6-year-old child. He required critical care admission for diagnosis and treatment (maximum number of platelets 7,283,000/mm(3)). We review the different causes of thrombocytosis in childhood, the differential diagnosis, and the available treatments in case of extreme thrombocytosis.