From the Guidelines
A platelet count of 1127 is significantly elevated, indicating thrombocytosis, which is a characteristic feature of Kawasaki disease (KD), but generally does not occur until the second week, peaking in the third week 1. This condition requires prompt medical evaluation to determine the underlying cause and appropriate treatment. The elevated platelet count increases the risk of blood clots (thrombosis) which can lead to serious complications like stroke, heart attack, or deep vein thrombosis.
Possible Causes and Treatment
- Reactive thrombocytosis (from infection, inflammation, iron deficiency, or recent surgery)
- Primary thrombocytosis from bone marrow disorders like essential thrombocythemia Treatment typically begins with low-dose aspirin (81-100mg daily) to reduce clot formation risk while the underlying cause is investigated.
Diagnostic Workup
- Complete blood count
- Peripheral blood smear
- Iron studies
- Inflammatory markers (such as ESR and CRP) 1
- Possibly bone marrow biopsy For primary thrombocytosis, cytoreductive therapy with hydroxyurea may be needed to lower platelet counts. Patients should stay well-hydrated and report any symptoms like headache, vision changes, chest pain, or swelling/pain in extremities immediately as these could indicate clot formation.
KD Diagnosis and Treatment
In the context of KD, thrombocytosis is a characteristic feature, but thrombocytopenia can be a sign of disseminated intravascular coagulation and is a risk factor for the development of coronary artery abnormalities 1. The CRP is more useful as a marker of inflammation after treatment of the acute illness 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Platelet Count and Essential Thrombocythemia
- A platelet count of 1127 is significantly higher than the normal range, which may indicate essential thrombocythemia, a clonal myeloproliferative neoplasm characterized by excessive platelet production 2.
- Patients with essential thrombocythemia have a persistent platelet count of 450 × 109/L or greater, and are at increased risk of thrombosis and bleeding 2.
- The differential diagnosis for essential thrombocythemia includes other myeloproliferative neoplasms, inflammatory conditions, infections, splenectomy, iron deficiency anemia, and solid tumors 2.
Risk of Thrombosis and Treatment
- Patients with essential thrombocythemia are at increased risk of arterial thrombosis, venous thrombosis, and hemorrhagic complications, with a median overall survival exceeding 35 years in those diagnosed at 40 years or younger 2.
- Use of aspirin (81-100 mg/d) is suggested for most patients with essential thrombocythemia to lower thrombosis risk, and cytoreductive therapy with hydroxyurea may be used for high-risk patients 2, 3.
- The extent of platelet inhibition by aspirin in patients with myeloproliferative neoplasms depends on their individual platelet count, with higher platelet counts associated with reduced platelet inhibition 4.
Platelet-Leukocyte Interactions and Aspirin Therapy
- Platelet-leukocyte interactions may contribute to the pathogenesis of thrombosis in essential thrombocythemia, and low-dose aspirin therapy has been shown to reduce platelet-leukocyte conjugates in patients with essential thrombocythemia 5.
- Aspirin therapy is generally recommended for low-risk patients, while hydroxyurea is used for high-risk patients, with the goal of preventing thrombosis and reducing the risk of disease transformation into myelofibrosis or acute myeloid leukemia 3.
Diagnosis and Risk Stratification
- Diagnosis of essential thrombocythemia requires exclusion of other myeloid neoplasms and typically involves bone marrow morphology showing increased mature-appearing megakaryocytes 3.
- Risk stratification is based on factors such as age, thrombosis history, and JAK2 mutation status, with four risk categories: very low, low, intermediate, and high 3.