Nighttime Dizziness and Polycythemia Vera
Dizziness, including nighttime dizziness, is a recognized symptom of polycythemia vera, occurring in 50-80% of patients as a manifestation of hyperviscosity from elevated red blood cell mass. 1
Mechanism and Clinical Presentation
- Dizziness in polycythemia vera results from blood hyperviscosity caused by increased red blood cell mass, which impairs cerebral blood flow and oxygen delivery 1
- This hyperviscosity-related symptom responds immediately to reduction of cell counts through phlebotomy, confirming its direct relationship to the elevated hematocrit 1
- Neurologic complications affect 50-80% of polycythemia vera patients, with dizziness being one of the most common presenting symptoms alongside headaches 1
Associated Microvascular Symptoms
- Microvascular disturbances from hyperviscosity commonly include headaches, visual disturbances, and dizziness as presenting symptoms 2
- Transient visual changes occur in 14% of patients, often accompanying dizziness as part of the hyperviscosity syndrome 3
- These symptoms can occur at any time during the disease course, including at night when patients may be more aware of subtle neurologic changes 1
Diagnostic Considerations
- When evaluating a patient with dizziness and suspected polycythemia vera, check for elevated hemoglobin (>16.5 g/dL in men, >16.0 g/dL in women) or hematocrit (>48% in women) 2
- Major symptoms in polycythemia rubra vera relate to arterial hypertension and arterial/venous thrombosis, which can manifest as dizziness 4
- The disease can remain undetected for years as erythrocytosis develops gradually, allowing physiologic adaptation that may mask symptoms until they become more pronounced 2
Treatment Response
- Therapeutic phlebotomy to maintain hematocrit <45% reduces hyperviscosity and resolves dizziness symptoms 4, 3
- The goal hematocrit of approximately 40-45% specifically addresses hyperviscosity-related neurologic symptoms including dizziness 1
- Low-dose aspirin 81 mg daily is recommended for all patients with polycythemia vera unless contraindicated 4, 3
Clinical Pitfall
- Do not dismiss nighttime dizziness as benign positional vertigo or age-related changes without checking a complete blood count, as polycythemia vera may present with vague neurologic symptoms that patients attribute to other causes 2