Polycythemia Vera: Clinical Manifestations
Polycythemia vera presents with a constellation of symptoms driven by hyperviscosity and increased red blood cell mass, most commonly including microvascular disturbances (headache, light-headedness, visual changes, tinnitus), pruritus (up to 48% of patients), and splenomegaly (36%), with many patients also experiencing thrombocytosis and leukocytosis. 1, 2
Microvascular and Hyperviscosity Symptoms
The hallmark symptoms result from increased blood viscosity and impaired microcirculation:
- Neurologic manifestations include headache, light-headedness, transient neurologic disturbances, and tinnitus—these are among the most common presenting complaints 1, 3
- Visual disturbances occur in approximately 14% of patients, presenting as transient ocular symptoms or visual changes 2
- Atypical chest discomfort and paresthesias are frequently reported microvascular symptoms 1
Dermatologic Manifestations
- Pruritus is documented in up to 48% of patients and represents one of the most bothersome symptoms, often triggered by warm water exposure 1, 2
- Erythromelalgia occurs in approximately 3-5.3% of patients, manifesting as painful burning sensations of the feet or hands with associated erythema and warmth 1, 2
Physical Examination Findings
- Splenomegaly is present in approximately 36% of patients at diagnosis and may cause abdominal discomfort 2, 4
- Plethoric appearance with facial ruddiness is a classic finding, though not universally present 5
Laboratory Abnormalities as Clinical Manifestations
- Thrombocytosis occurs in 53% of patients 2
- Leukocytosis is present in 49% of patients 2
- Elevated hemoglobin/hematocrit (>16.5 g/dL/49% in men or >16 g/dL/48% in women) is the defining feature 6
Thrombotic and Hemorrhagic Complications
These represent the most serious clinical manifestations affecting morbidity and mortality:
- Arterial thrombosis occurs in 16% of patients prior to or at diagnosis 2
- Venous thrombotic events occur in 7% of patients, often involving unusual sites such as splanchnic veins 2
- Bleeding risk is increased, especially with extreme thrombocytosis (platelet count ≥1000 × 10⁹/L) due to acquired von Willebrand disease 2
Constitutional Symptoms
- Patients may experience fatigue, night sweats, and weight loss, though these are less specific 4
Important Clinical Pitfalls
Many patients are asymptomatic at diagnosis, with PV discovered incidentally on routine blood work. The median age at diagnosis is approximately 60 years with slight male predominance (1.2:1), though 7% of patients are diagnosed before age 40 years 7. The presence of JAK2 mutation (>95% of cases) is crucial for distinguishing PV from secondary causes of erythrocytosis such as smoking, sleep apnea, or chronic lung disease 1, 2.
The 20-year risk for major complications includes approximately 26% for thrombosis, 16% for progression to myelofibrosis, and 4% for acute myeloid leukemia 6, 8. These risks underscore why symptom recognition and early diagnosis are critical for preventing life-threatening complications through appropriate therapeutic intervention with phlebotomy and cytoreductive therapy when indicated.