eMedicine Specialties > Pediatrics: General Medicine > Hematology
Thrombocytosis: Treatment & Medication
Updated: Jul 28, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Treatment
Medical Care
No treatment is necessary for reactive thrombocytosis. Rarely, in patients who have reactive thrombocytosis and a known risk factor for thrombosis, such as factor V Leiden mutation, the thrombotic risk may be increased. However, no information is currently available regarding the magnitude of the risk. Therefore, one should consider each case individually for prophylaxis of thrombosis. In vasculitis syndrome with thrombocytosis (in particular, in Kawasaki syndrome), treatment with aspirin is recommended (see Kawasaki Disease).13 In primary thrombocytosis, prophylactic use of antithrombotic agents has not been well delineated. In general, platelet-lowering agents have been recommended for high-risk patients (all adults) with an increased cardiovascular risk, have a previous history of thrombosis, or who are older than 60 years (see Medication).
In patients in whom primary thrombocytosis is strongly suspected, laboratory studies mentioned in the previous section and evaluation of family members may be needed to confirm the diagnosis. Morphologic and cytogenetic examination of bone-marrow cells and marrow reticulin stains should be repeated in patients with a changing hematologic picture (refer patients to a hematologist). Evolution of primary thrombocytosis to frank acute myeloblastic leukemia (AML), myelofibrosis/agnogenic myeloid metaplasia (AMM), or myelodysplastic syndrome (MDS) has been documented in adults and represents a progression of disease. The prognosis after this progression is poor. However, successful allogeneic bone-marrow or stem-cell transplantation has been reported in patients who developed AML/MDS and/or myelofibrosis. Therefore, keep this modality in mind when treating primary thrombocytosis.
Consultations
A persistent increase in neutrophil counts with immature forms (eg, metamyelocytes, myelocytes), as persistent increase in basophils and eosinophils, and splenomegaly suggest a chronic myelocytic leukemia (CML). Kastan et al described 2 children whose clinical findings and blood counts best fit essential thrombocytosis (ET) but whose bone-marrow cytogenetic analyses showed the presence of the Philadelphia (Ph1) chromosome.14 Both of these patients presented with platelet counts in excess of 2000 X 109/L.
A persistent increase in the hematocrit (with or without a change in the WBC count) with thrombocytosis suggests polycythemia vera. Media file 1 shows suggested workup algorithm for thrombocytosis.
Algorithm for thrombocytosis workup and potential need for medication.
One should consult a hematologist if a workup for ET is needed. Older children with thrombocytosis with thrombosis (suspected or demonstrated) or a history of thrombosis, increased bleeding tendency despite thrombocytosis, or splenomegaly must promptly be referred to a hematologist.
Activity
No medical reason warrants the limitation or encouragement of activity in a child with thrombocytosis. A child with a substantially enlarged spleen (usually caused by essential or familial thrombocythemia) requires necessary precautions regarding their activity to prevent splenic rupture.
Medication
In a child with reactive thrombocytosis, drug therapy is not required. Thrombohemorrhagic complications are exceedingly rare. To date, no studies have demonstrated a benefit of prophylactic use of antithrombotic or antiplatelet agents. In general, use of these drugs is not warranted. One exception in which antithrombotic or antiplatelet drugs should be used is for Kawasaki syndrome. A clear guideline for aspirin use with this syndrome has been established (see Kawasaki Disease).
Symptomatic patients with essential thrombocytosis (ET) should receive treatment to lower their platelet count. For pediatric use, anagrelide or hydroxyurea is recommended. In a study by Harrison et al, adult patients (median age, about 60 y) were randomly assigned to receive low-dose aspirin plus hydroxyurea or anagrelide.15 Significantly more patients in the anagrelide arm than in the hydroxyurea arm reached the study endpoint. The authors concluded that hydroxyurea plus aspirin was more effective than anagrelide plus aspirin in preventing complications in adults with ET.
Radioactive phosphorus should not be used for young patients because of its carcinogenic potential.
Use of pharmacologic agents to prevent thrombotic complications in primary or ET is controversial, even in the internal medicine literature, because no laboratory studies offer predictive value in terms of the risk of thrombosis or hemorrhage. Tefferi et al recommend their use in only patients older than 60 years, individuals with a history of thrombosis, or persons with cardiovascular risk factors, virtually eliminating pediatric patients.16
Patients who do develop a thrombosis should be treated appropriately (see Thromboembolism).
Agents to reduce platelet count and reduce platelet function
These agents are used to treat thrombotic complications and to prevent thrombosis (in some cases) in patients with an established diagnosis of ET.
Anagrelide (Agrylin)
Specifically lowers platelet count, presumably by reducing megakaryocyte size and ploidy. Not FDA approved for use in patients <16 y, but a small number of pediatric patients have been treated without significant adverse effects. Long-term adverse effects totally unknown; therefore, clearly positive benefit-risk ratio must be shown before administering drug to any child.
Adult
0.5 mg PO qid or 1 mg PO bid initially; maintain dose for 1 wk, then adjust to maintain platelet count in reference range
Pediatric
Not established
According to the manufacturer's (Shire US) package insert, 12 patients aged 6.8-17.4 y started treatment with 0.5 mg PO qid to maximum of 10 mg/d
Sucralfate may decrease absorption of anagrelide
Documented hypersensitivity
Pregnancy
C - Safety for use during pregnancy has not been established.
Precautions
Caution in suspected heart disease, reduced renal function, or hepatic dysfunction; thrombocytopenia appears to be main dose-limiting adverse effect
Cytoreductive agents
These agents should be used only in patients with thrombotic complications (or in some in need of prevention of thrombosis) with an established diagnosis of primary thrombocythemia.
Hydroxyurea (Hydrea)
Inhibits DNA synthesis (RNA reductase inhibitor), reducing all 3 blood cell counts.
Adult
20-30 mg/kg/d PO qd initially; after 2 wk, adjust dose by frequently monitoring platelet count
Pediatric
Administer as in adults
Coadministration with fluorouracil can increase neurotoxicity
Documented hypersensitivity; severe anemia or bone marrow suppression
Pregnancy
D - Unsafe in pregnancy
Precautions
Mutagenic (benefit must outweigh risk, this rare complication is related to previous treatment with mutagenic agents); patients should not become pregnant while taking drug; frequent monitoring of blood counts required
More on Thrombocytosis |
| Overview: Thrombocytosis |
| Differential Diagnoses & Workup: Thrombocytosis |
 Treatment & Medication: Thrombocytosis |
| Follow-up: Thrombocytosis |
| Multimedia: Thrombocytosis |
| References |
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References
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Further Reading
Keywords
thrombocytosis, essential thrombocythemia, primary thrombocythemia, idiopathic thrombocythemia, primary thrombocytosis, secondary thrombocytosis, reactive thrombocytosis, myeloproliferative disorder, myelofibrosis with myeloid metaplasia, polycythemia vera, chronic myelocytic leukemia, acute myelocytic leukemia, platelet count, thrombopoietin, TPO, interleukin 6, IL-6, treatment, diagnosis, bacterial meningitis, pneumonia, hemolytic anemia, iron-deficiency anemia, chronic myelogenous leukemia, upper respiratory tract infections, lower respiratory tract infections, septic arthritis, osteomyelitis, urinary tract infection, gastroenteritis, sepsis, severe dermatitis, rheumatoid arthritis, Kawasaki disease, inflammatory bowel disease, sickle cell disease, thalassemia, nephrotic syndrome, nephritis, soft tissue sarcoma, osteosarcoma, treatment, diagnosis
