Polycythemia: When the Blood Gets Too Thick

General
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Polycythemia refers to an abnormal increase in red blood cell (RBC) mass, leading to elevated hematocrit and hemoglobin levels. The resultant increase in blood viscosity predisposes patients to hyperviscosity symptoms and thrombotic complications, including stroke, myocardial infarction, and deep vein thrombosis.

Classification and Etiology:

  • Primary Polycythemia (Polycythemia Vera):
    A myeloproliferative neoplasm driven predominantly by a JAK2 V617F mutation, resulting in autonomous erythropoiesis independent of erythropoietin (EPO) regulation.

  • Secondary Polycythemia:
    Caused by elevated EPO levels secondary to chronic hypoxia (e.g., chronic obstructive pulmonary disease, high-altitude exposure, cyanotic heart disease) or EPO-secreting tumors (e.g., renal cell carcinoma).

  • Relative Polycythemia:
    Represents hemoconcentration due to plasma volume depletion rather than true RBC proliferation, often seen in dehydration or stress states (Gaisböck syndrome).

Clinical Features and Management:
Patients may present with headache, dizziness, plethora, pruritus after bathing, and visual disturbances.

Diagnostic workup includes CBC, EPO levels, JAK2 mutation testing, and bone marrow evaluation. Management aims to reduce hematocrit below 45% through therapeutic phlebotomy, cytoreductive therapy (e.g., hydroxyurea), and low-dose aspirin to mitigate thrombotic risk.

Timely diagnosis and vigilant monitoring are essential to prevent vascular complications and disease progression to myelofibrosis or acute leukemia.

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Informative.

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Polycythemia is a serious but often under-recognized condition. It’s fascinating how an increase in red blood cells something we usually associate with strength can actually thicken the blood and raise the risk of stroke or heart attack. Early detection really matters here, especially since symptoms like headache or itching after a bath can easily be overlooked With proper monitoring, phlebotomy, and medication, patients can lead stable lives and avoid major complications. It’s a great reminder of how balancing the body’s systems is key to overall health.