From the Guidelines
Therapeutic phlebotomy is not recommended for this patient with a hemoglobin level of 18 g/dL and hematocrit of 51.4% in the absence of symptoms of hyperviscosity, as the risks of iron depletion and decreased oxygen-carrying capacity outweigh the benefits 1. The CBC results show elevated red blood cell count (RBC), hemoglobin, and hematocrit levels, which suggest polycythemia or erythrocytosis. The RBC of 5.98 million/μL, hemoglobin of 18 g/dL, and hematocrit of 51.4% are all above normal ranges. Some key points to consider in this patient's management include:
- The low mean platelet volume (MPV) of 4.4 fL is below the normal range, indicating smaller than average platelets.
- The patient's elevated red cell parameters can increase blood viscosity and the risk of clotting events.
- The low MPV may affect platelet function.
- According to the acc/aha 2008 guidelines, therapeutic phlebotomy is only recommended for patients with hemoglobin greater than 20 g/dL and hematocrit greater than 65%, associated with symptoms of hyperviscosity 1.
- Repeated routine phlebotomies are not recommended due to the risk of iron depletion, decreased oxygen-carrying capacity, and stroke 1. Further investigation is necessary to determine the underlying cause of the patient's polycythemia, and consulting with a hematologist for additional testing, including JAK2 mutation analysis, erythropoietin levels, and arterial oxygen saturation, is recommended. Proper hydration is also important to help manage the patient's condition.
From the Research
Complete Blood Count (CBC) Results
The provided CBC results are:
- RBC: 5.98
- MPV: 4.4
- Hemoglobin: 18
- Hematocrit: 51.4
Interpretation of CBC Results
According to the study 2, a complete blood cell count (CBC) is one of the most common laboratory tests in medicine, and it is essential to have a structured action plan when confronted with abnormal CBC results. The provided CBC results show elevated hemoglobin and hematocrit levels, which may indicate polycythemia.
Polycythemia Vera (PV)
The study 3 states that polycythemia vera (PV) is a myeloproliferative neoplasm characterized by an increased red blood cell mass and increased risk of thrombosis. Erythrocytosis (hemoglobin >16.5 mg/dL in men or >16.0 mg/dL in women) is a required diagnostic criterion for PV. The patient's hemoglobin level is 18, which is above the diagnostic threshold.
Risk of Thrombosis
The study 4 found that patients with PV who require frequent phlebotomies have a higher risk of thrombosis. The study 5 also found that phlebotomy and hydroxyurea are associated with improved overall survival and decreased risk of thrombosis in older patients with PV.
Management of PV
The study 3 recommends that all patients with PV should receive therapeutic phlebotomy (goal hematocrit, <45%) and low-dose aspirin (if no contraindications). Patients who are at higher risk of thrombosis may benefit from cytoreductive therapy with hydroxyurea or interferon. The study 6 discusses the management of hydroxyurea-resistant or intolerant PV, including the use of interferon, ruxolitinib, and other agents.
Key Points
- Elevated hemoglobin and hematocrit levels may indicate polycythemia vera (PV) 3
- PV is associated with an increased risk of thrombosis 3, 4, 5
- Therapeutic phlebotomy and low-dose aspirin are recommended for all patients with PV 3
- Cytoreductive therapy with hydroxyurea or interferon may be beneficial for patients at higher risk of thrombosis 3, 6