Snapshot A 63-year-old man presents to urgent care with painful fingers and toes. He complains of a burning sensation, especially in the afternoon when the temperature is highest. He has had similar episodes in the past which resolve on its own. However, today his fingers are particularly painful. On review of systems, he reveals that he is fatigued and experiences night sweats and regular headaches. His weight today is 20 lbs lighter than his previous documented weight. Concerned, his physician orders a complete blood count and serum EPO level, both of which come back abnormal. His hemoglobin is 17 g/dL and his EPO level is well below normal. However, his peripheral blood smear shows RBC precursor cells. Introduction Myeloproliferative neoplasm with primarily increased production of RBCs Epidemiology Presentation in the 60s-70s Male and females equally affected Potentially more prevalent in those of Ashkenazi Jewish descent etiology Pathogenesis login to view 6 more bullets Associated conditions login to view 1 more bullet Presentation Symptoms login to view 17 more bullets Physical exam login to view 4 more bullets STUDIES Complete blood count with smear login to view 2 more bullets Bone marrow biopsy with hypercellularity login to view 4 more bullets JAK2 mutation in peripheral blood – most accurate ↓ serum EPO login to view 1 more bullet ↓ MCV SaO2 normal login to view 1 more bullet Differential Diagnosis Secondary polycythemia Tumor-driven polycythemia Other myeloproliferative neoplasm DIAGNOSIS Bone marrow biopsy with hypercellularity confirms diagnosis Treatment For low risk patients (< 60 years old and no prior thrombosis) login to view 3 more bullets For high risk patients ( ≥ 60 years old and/or prior thrombosis) login to view 5 more bullets Gout prophylaxis login to view 1 more bullet Pruritus login to view 1 more bullet Complications Thrombosis login to view 4 more bullets Hemorrhage Peptic ulcers login to view 1 more bullet Gout Progression to login to view 3 more bullets Prognosis > 10 years with treatment 1.6x higher mortality than general population