From the Guidelines
Polycythemia is considered a medical emergency when it presents with severe symptoms or a hematocrit level exceeding 60%, requiring immediate intervention to prevent life-threatening complications. The management of polycythemia vera (PV) involves phlebotomy to maintain the hematocrit below 45%, as strongly recommended by the European LeukemiaNet panel 1.
Key Considerations
- The induction phase of phlebotomy should involve removing 300 to 450 ml of blood weekly or twice weekly until the hematocrit target is reached, as outlined in the management recommendations for PV 1.
- Cytoreduction is strongly recommended in high-risk cases, such as patients older than 60 years or those with a previous thrombotic event, and may involve the use of hydroxyurea or interferon-alpha as first-line therapy 1.
- The goal of emergency management is to rapidly reduce blood viscosity and prevent complications such as thrombosis, stroke, or heart attack, with careful monitoring of vital signs and symptoms.
- Following emergency management, patients require investigation into the underlying cause of their polycythemia, which may be primary or secondary, and long-term management may include cytoreductive therapy or addressing the underlying cause.
Management Strategies
- Phlebotomy is the primary treatment for reducing hematocrit levels and blood viscosity in emergency situations, with the aim of reducing the hematocrit to less than 45% 1.
- Hydration is essential during the phlebotomy process to maintain blood volume and prevent dehydration.
- Cytoreductive therapy may be necessary for patients with high-risk PV or those who are intolerant to phlebotomy, with hydroxyurea or interferon-alpha being suitable options 1.
From the Research
Emergence of Polycythemia
- Polycythemia vera (PV) is a relatively indolent myeloid neoplasm with a median survival that exceeds 35 years in young patients 2.
- The natural history of PV might be interrupted by thrombotic, fibrotic, or leukemic events, with respective 20-year rates of 26%, 16%, and 4% 2.
- PV is associated with an increased risk of arterial and venous thrombosis, hemorrhage, myelofibrosis, and acute myeloid leukemia 3.
Risk Factors and Diagnosis
- Risk factors for thrombosis in PV include age and prior thrombosis 2, 4.
- The presence of a JAK2 gene variant helps distinguish PV from secondary causes of erythrocytosis 3, 5, 6.
- Bone marrow morphology remains the cornerstone of diagnosis, and the presence of JAK2 mutation is expected in PV 5, 6.
Treatment and Management
- All patients with PV require phlebotomy to keep hematocrit below 45% and once-daily low-dose aspirin, in the absence of contraindications 2, 3, 5.
- Cytoreductive therapy is recommended for high-risk or symptomatic low-risk disease, with hydroxyurea as the first-line drug of choice 2, 3, 5.
- Ruxolitinib is a Janus kinase inhibitor that can alleviate pruritus and decrease splenomegaly in patients who are intolerant of or resistant to hydroxyurea 2, 3.