From the Guidelines
For a 56-year-old male with CKD stage 3A (GFR 56), hypertension, hyperlipidemia, and unexplained mild polycythemia without symptoms, I recommend obtaining a complete blood count with differential, comprehensive metabolic panel, erythropoietin level, and JAK2 mutation testing before considering hematology referral. These tests will help determine if this represents secondary polycythemia from his kidney disease or a potential myeloproliferative disorder 1. Since the patient is asymptomatic with mild elevation, watchful waiting with serial hematocrit measurements every 3-6 months is reasonable while completing the workup. If hematocrit exceeds 52% or if symptoms develop (headaches, dizziness, visual disturbances), therapeutic phlebotomy should be considered to maintain hematocrit below 45-48%.
Management of Underlying Conditions
Ensure optimal management of underlying CKD and hypertension, as these conditions can contribute to erythrocytosis. According to the JNC-8 guidelines, the goal blood pressure for patients with CKD is less than 140/90 mm Hg 1. Smoking cessation should be emphasized if applicable, as smoking can cause secondary polycythemia. Sleep apnea screening is also warranted as it's a common cause of secondary polycythemia.
Lipid Management
For patients with CKD, dyslipidemia management should be undertaken in conjunction with all other available measures to reduce the overall risk of atherosclerotic cardiovascular disease (ACVD) 1. Modifiable, conventional, risk factors (including hypertension, cigarette smoking, glucose intolerance or diabetes control, and obesity) should be assessed at initial presentation and at least yearly thereafter.
Referral to Hematology
If JAK2 mutation is positive or if polycythemia worsens despite management of secondary causes, referral to hematology is indicated for evaluation of possible polycythemia vera or other myeloproliferative disorders. This approach prioritizes the patient's morbidity, mortality, and quality of life by addressing potential underlying causes of polycythemia and managing related conditions.
From the Research
Patient Profile
- 56-year-old male with a past medical history (PMH) of:
- Chronic Kidney Disease (CKD) stage 3A with a Glomerular Filtration Rate (GFR) of 56
- Hypertension (HTN)
- Hyperlipidemia
- Presents with unexplainable mild polycythemia, not on testosterone or any other explainable cause
- Asymptomatic
Diagnostic Considerations
- Polycythemia vera (PV) and essential thrombocythemia (ET) are myeloproliferative neoplasms that may present with erythrocytosis, leukocytosis, and thrombocytosis 2
- The presence of JAK2 mutation is expected in PV, while ET may express mutually exclusive JAK2, CALR, or MPL mutations 2
- Intermittent hypoxia may be a potent stimulus to erythropoiesis, and nocturnal hypoxia should be considered in patients with unexplained polycythemia 3
- Gaisböck syndrome, characterized by polycythemia and hypertension, may be relevant in this patient's case, given his history of HTN 4
Management and Referral
- Referral to hematology may be necessary to further evaluate and manage the patient's polycythemia 2, 5
- Additional testing, such as bone marrow morphology and JAK2 mutation screening, may be required to diagnose PV or ET 2, 6
- The patient's CKD and erythrocytosis should be managed concurrently, with consideration of the potential causes and consequences of erythrocytosis in CKD patients 6
Potential Causes and Associations
- CKD may be associated with erythrocytosis due to various causes, including cystic kidney diseases, kidney or other erythropoietin-secreting neoplasms, and high-altitude renal syndrome 6
- The use of sodium/glucose cotransporter 2 (SGLT2) inhibitors may induce erythrocytosis by activating hypoxia-inducible factor 2α (HIF-2α) and unmasking PV 6