ImportancePolycythemia vera (PV), a myeloproliferative neoplasm characterized by an increased red blood cell mass and increased risk of thrombosis, affects approximately 65 000 people in the US, with an annual incidence of 0.5 to 4.0 cases per 100 000 persons.ObservationsErythrocytosis (hemoglobin >16.5 mg/dL in men or >16.0 mg/dL in women) is a required diagnostic criterion, although thrombocytosis (53%) and leukocytosis (49%) are common. Patients may have pruritus (33%), erythromelalgia (5.3%), transient visual changes (14%), and splenomegaly (36%) with abdominal discomfort. More than 95% of patients have a JAK2 gene variant, which helps distinguish PV from secondary causes of erythrocytosis, such as tobacco smoking or sleep apnea. Among 7 cohorts (1545 individuals), the median survival from diagnosis was 14.1 to 27.6 years. Prior to or at the time of PV diagnosis, arterial thrombosis occurred in 16% of patients and 7% had venous thrombotic events, which could involve unusual sites, such as splanchnic veins. PV is also associated with an increased bleeding risk, especially in patients with acquired von Willebrand disease, which can occur with extreme thrombocytosis (platelet count, ≥1000 × 109/L). 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 include those aged 60 years or older or with a prior thrombosis. These patients and those with persistent PV symptoms may benefit from cytoreductive therapy with hydroxyurea or interferon to lower thrombosis risk and decrease symptoms. Ruxolitinib is a Janus kinase inhibitor that can alleviate pruritus and decrease splenomegaly in patients who are intolerant of or resistant to hydroxyurea. About 12.7% of patients with PV develop myelofibrosis and 6.8% develop acute myeloid leukemia.Conclusions and RelevancePV is a myeloproliferative neoplasm characterized by erythrocytosis and is almost universally associated with a JAK2 gene variant. PV is associated with an increased risk of arterial and venous thrombosis, hemorrhage, myelofibrosis, and acute myeloid leukemia. To decrease the risk of thrombosis, all patients with PV should be treated with aspirin and therapeutic phlebotomy to maintain a hematocrit of less than 45%. Cytoreductive therapies, such as hydroxyurea or interferon, are recommended for patients at high risk of thrombosis.

中文翻译：

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真性红细胞增多症的诊断和治疗


重要性真性红细胞增多症 （PV） 是一种骨髓增生性肿瘤，其特征是红细胞量增加和血栓形成风险增加，在美国影响约 65 000 人，年发病率为每 100 000 人 0.5 至 4.0 例。观察结果红细胞增多症（血红蛋白 >男性 16.5 mg/dL 或 >女性 16.0 mg/dL）是必需的诊断标准，但血小板增多 （53%） 和白细胞增多 （49%） 很常见。患者可能有瘙痒 （33%）、红斑性肢痛症 （5.3%）、短暂性视力改变 （14%） 和脾肿大 （36%），伴有腹部不适。超过 95% 的患者具有 JAK2 基因变异，这有助于区分 PV 与红细胞增多症的继发性原因，例如吸烟或睡眠呼吸暂停。在 7 个队列 （1545 人） 中，诊断后的中位生存期为 14.1 至 27.6 年。在 PV 诊断之前或之时，16% 的患者发生动脉血栓形成，7% 的患者发生静脉血栓形成事件，这可能涉及不寻常的部位，例如内脏静脉。PV 还与出血风险增加有关，尤其是在获得性血管性血友病患者中，这种疾病可能发生在极度血小板增多（血小板计数，≥1000 × 109/L）中。所有 PV 患者都应接受治疗性静脉切开术（目标血细胞比容，<45%）和低剂量阿司匹林（如果没有禁忌证）。血栓形成风险较高的患者包括 60 岁或以上或既往有血栓形成史的患者。这些患者和有持续性 PV 症状的患者可能受益于羟基脲或干扰素的细胞减灭治疗，以降低血栓形成风险并减轻症状。 Ruxolitinib 是一种 Janus 激酶抑制剂，可以缓解对羟基脲不耐受或耐药的患者的瘙痒并减少脾肿大。约 12.7% 的 PV 患者发展为骨髓纤维化，6.8% 发展为急性髓性白血病。结论和相关性PV 是一种以红细胞增多症为特征的骨髓增生性肿瘤，几乎普遍与 JAK2 基因变异相关。PV 与动脉和静脉血栓形成、出血、骨髓纤维化和急性髓性白血病的风险增加有关。为了降低血栓形成的风险，所有 PV 患者都应接受阿司匹林和治疗性静脉切开术治疗，以维持低于 45% 的血细胞比容。建议血栓形成高风险患者使用细胞减灭疗法，例如羟基脲或干扰素。