What is the significance of elevated Hemoglobin (Hb) and Hematocrit (Hct) levels in a 68-year-old male?

From the Guidelines

This patient requires immediate referral to a hematologist for evaluation and management of possible polycythemia vera or secondary polycythemia, with initial management including therapeutic phlebotomy to reduce hematocrit to below 0.45 L/L, as recommended by the most recent guidelines 1. The patient's elevated hemoglobin (179 g/L) and hematocrit (0.54 L/L) levels are above normal ranges, indicating polycythemia.

Key Considerations

• The diagnosis of polycythemia vera (PV) or essential thrombocythemia (ET) should be considered, with further workup including JAK2 mutation testing, serum erythropoietin levels, and evaluation for secondary causes such as hypoxemia, smoking, or renal disease 1.
• Therapeutic phlebotomy is recommended to reduce the risk of thrombotic events, including stroke, myocardial infarction, and venous thromboembolism, which is increased due to elevated blood viscosity from high red cell mass 1.
• Low-dose aspirin (81-100 mg daily) is recommended to reduce thrombotic risk unless contraindicated.
• Hydration should be maintained before and after phlebotomy to prevent dehydration and ensure safe removal of blood.
• The frequency of phlebotomy should be determined by response, with the goal of reducing hematocrit to below 0.45 L/L.
• Cytoreductive therapy with hydroxyurea may be indicated for patients with confirmed polycythemia vera, particularly in high-risk patients (age >60 or history of thrombosis).

Management

• Initial management should include therapeutic phlebotomy, with removal of 450-500 mL of blood per session, as recommended by recent guidelines 1.
• Further workup and evaluation should be performed to determine the underlying cause of polycythemia and to guide subsequent management.
• The patient should be closely monitored for signs of thrombosis, bleeding, or other complications, and managed accordingly.
• The importance of maintaining hydration and avoiding iron deficiency should be emphasized, as iron deficiency can increase the risk of stroke and other complications 1.

From the Research

Patient Information

• Age: 68 years old
• Hemoglobin (Hb): 179 g/L
• Hematocrit: 0.54 L/L

Diagnosis and Treatment

• The patient's hematocrit level is above the normal range, which may indicate erythrocytosis, a characteristic of polycythemia vera (PV) 2, 3, 4, 5.
• PV is a myeloproliferative neoplasm that increases the risk of thrombosis, and treatment aims to prevent thrombotic events 2, 3, 4, 5.
• The World Health Organization's major diagnostic criteria for PV include an elevated hemoglobin or hematocrit level, abnormal results on bone marrow biopsy, and presence of the Janus kinase 2 genetic mutation 5.

Treatment Options

• First-line treatments for PV include low-dose aspirin and goal-directed phlebotomy to a hematocrit level of less than 45% to reduce thrombotic events 2, 3, 4, 5.
• Cytoreductive therapy, primarily with hydroxyurea, can be added when indicated, with consideration of second-line agents such as pegylated interferon-alfa, busulfan, and ruxolitinib 2, 3, 4, 5.
• Smoking cessation and cardiometabolic disease management are also important to reduce the risk of thrombosis 5.

Thrombotic Risk

• Elevated hematocrit is often associated with an increased risk of thrombosis, but other factors, such as leukocytosis and abnormal karyotype, can also contribute to thrombotic risk 2, 3, 4, 6.
• The relationship between hematocrit and thrombotic risk is complex, and other cellular changes may directly affect thrombotic risk, irrespective of the elevated hematocrit 6.