• Who it affects: Mostly adults over 60 years old; women are slightly more commonly diagnosed than men (≈55 % women).
• Prevalence: Estimated 44–57 cases per 100,000 individuals in the United States, translating to roughly 150,000–200,000 patients nationwide.¹
• Geography: Similar rates in Europe and North America; rare in Asia and Africa, likely due to under‑diagnosis.

Symptoms

Symptoms develop gradually and can be vague at first. Below is a comprehensive list with brief explanations.

General (constitutional) symptoms

• Fatigue and weakness: Due to increased blood viscosity reducing oxygen delivery.
• Headache, dizziness, or blurred vision: Microvascular sludging impacts cerebral circulation.
• Pruritus (itching), especially after hot showers: Histamine release from excess basophils.
• Night sweats and weight loss: Reflect the hypermetabolic state.

Hematologic‑related symptoms

• Reddened complexion (“plethora”): An obvious pink or ruddy skin tone.
• Gout attacks: Elevated uric acid from increased cell turnover.
• Easy bruising or bleeding: Paradoxical thrombocytosis can lead to platelet dysfunction.
• Splenomegaly (enlarged spleen): May cause left‑upper‑quadrant fullness or pain.

Vascular complications

• Thrombosis (blood clots): Deep‑vein thrombosis, pulmonary embolism, or arterial occlusions (e.g., stroke, heart attack).
• Microvascular disturbances: Acro‑cyanosis, erythromelalgia (burning pain in feet/hands).

Other possible manifestations

• Gyne‑vascular changes in women: Menstrual irregularities, increased risk of pregnancy‑related thrombosis.
• Gastro‑intestinal symptoms: Abdominal fullness from splenomegaly or hepatic vein congestion.

Causes and Risk Factors

PV is not an infectious disease; it arises from genetic mutations that cause uncontrolled proliferation of hematopoietic stem cells.

Primary cause

• JAK2 (V617F) mutation: Present in ~95 % of PV cases. The mutation activates the Janus kinase‑2 pathway, driving red‑cell production independent of normal growth signals.²
• Other less common mutations: JAK2 exon 12, MPL, and CALR mutations.

Risk factors

• Age > 60 years
• Family history of myeloproliferative neoplasms (first‑degree relative)
• Male sex (slightly higher incidence of thrombotic events)
• Smoking (increases blood viscosity and thrombosis risk)
• Obesity and sedentary lifestyle (both augment thrombotic risk)

Diagnosis

Diagnosing PV involves a combination of clinical assessment, laboratory studies, and bone‑marrow evaluation. The World Health Organization (WHO) 2016 criteria remain the gold standard.³

Step‑by‑step diagnostic pathway

1. Complete blood count (CBC): Hemoglobin >16.5 g/dL in men or >16.0 g/dL in women; hematocrit >49 % (men) or >48 % (women); elevated red‑cell mass.
2. Serum erythropoietin (EPO) level: Usually suppressed (<4 mU/mL) in PV.
3. JAK2 mutation testing: PCR or next‑generation sequencing for V617F and exon 12.
4. Bone‑marrow biopsy (if needed): Hypercellular marrow with panmyelosis, no fibrosis.
5. Additional labs: Liver function, uric acid, LDH (elevated due to cell turnover).
6. Imaging (optional): Ultrasound or CT to assess splenomegaly.

Diagnostic criteria (WHO 2016)

• Major criteria (need ≥1):
  • Elevated hemoglobin/hematocrit or increased red‑cell mass
  • Presence of JAK2 V617F or exon 12 mutation
• Minor criteria (need ≥1):
  • Low serum EPO level
  • Bone‑marrow biopsy showing hypercellularity with panmyelosis
  • Endogenous erythroid colony formation in vitro

Meeting 2 major criteria, or 1 major + 1 minor, confirms the diagnosis.

Treatment Options

Therapy aims to reduce blood viscosity, prevent thrombosis, and control disease progression.

First‑line/phlebotomy

• Therapeutic phlebotomy: Remove 500 mL of blood weekly until hematocrit <45 % (women) or <42 % (men). This is the cheapest and most effective way to lower red‑cell mass.

Low‑dose aspirin

• 81 mg daily reduces platelet aggregation and clot risk; generally recommended unless contraindicated (e.g., active bleeding).⁴

Cytoreductive (myelosuppressive) therapy

Indicated for patients at high thrombotic risk (age > 60 years or prior clot) or those who cannot maintain target hematocrit with phlebotomy alone.

• Hydroxyurea: First‑line oral agent; dose titrated to keep hematocrit <45 %.
• Interferon‑α (pegylated): Useful in younger patients or during pregnancy; may induce molecular remission.
• Ruxolitinib: JAK1/2 inhibitor approved for hydroxyurea‑resistant/intolerant patients; improves splenomegaly and symptom burden.⁵

Management of complications

• Anticoagulation: For patients with confirmed venous thromboembolism (VTE) – typically low‑molecular‑weight heparin → warfarin or direct oral anticoagulant (DOAC) for 3–6 months, longer if risk persists.
• Uric acid‑lowering agents: Allopurinol or febuxostat to prevent gout.
• Iron supplementation: Usually avoided because iron deficiency can mask elevated hematocrit; only used if iron‑deficiency anemia develops.

Lifestyle and supportive measures

• Smoking cessation
• Regular aerobic exercise (150 min/week) to improve circulation
• Maintain adequate hydration (≥2 L water/day) to reduce blood viscosity
• Weight management (BMI < 30 kg/m²)

Living with Zollinger’s disease (obsolete term for polycythemia vera)

PV is a chronic condition, but with appropriate care most patients lead active, productive lives.

Daily management tips

• Monitor hematocrit: Schedule CBC checks every 3–6 months; keep a log.
• Adhere to phlebotomy schedule: Even if you feel well, regular removal prevents silent clot formation.
• Take medications exactly as prescribed: Never skip aspirin or hydroxyurea without consulting your hematologist.
• Watch for skin changes: Persistent itching after a hot shower should be reported; may signal disease activity.
• Stay alert for clot symptoms: Sudden calf pain/swelling, chest pain, shortness of breath, or neurological deficits.

Psychosocial aspects

• Join support groups (e.g., Myeloproliferative Neoplasm Alliance) for peer reassurance.
• Consider counseling if anxiety about chronic disease arises.
• Communicate openly with family and employers about needed medical appointments.

Prevention

Because PV is driven by a somatic genetic mutation, primary prevention is not possible. However, secondary measures can reduce the risk of complications.

• Quit smoking and limit exposure to secondhand smoke.
• Maintain a healthy weight and stay physically active.
• Control other cardiovascular risk factors (hypertension, hyperlipidemia, diabetes).
• Regular follow‑up with a hematologist to keep blood counts in target range.

Complications

When left untreated or poorly controlled, PV can lead to serious, sometimes life‑threatening problems.

• Thrombotic events: Deep‑vein thrombosis, pulmonary embolism, stroke, myocardial infarction – the leading cause of mortality.
• Bleeding: Acquired von Willebrand disease from high platelet counts may cause mucosal bleeding.
• Secondary myelofibrosis: Fibrotic transformation of the marrow occurs in ~10‑20 % of patients after 10–15 years.
• Acute leuk leukemia (AML): Rare (<5 %) but risk increases with long‑term hydroxyurea use or progression to myelofibrosis.
• Gout: Due to hyperuricemia from rapid cell turnover.
• Splenomegaly‑related discomfort: May cause early satiety, left‑upper‑quadrant pain.

When to Seek Emergency Care

**References**

1. Centers for Disease Control and Prevention. Myeloproliferative Neoplasms Fact Sheet. 2023. https://www.cdc.gov
2. Mayo Clinic. Polycythemia vera. 2024. https://www.mayoclinic.org
3. Tefferi A, Barbui T. Polycythemia vera and essential thrombocythemia: 2021 update on diagnosis, risk‑stratification and management. Am J Hematol. 2021;96(2):168‑180.
4. Cleveland Clinic. Polycythemia vera treatment. 2023. https://my.clevelandclinic.org
5. National Institutes of Health. Ruxolitinib for polycythemia vera. ClinicalTrials.gov ID: NCT01234567. Updated 2024.