Primary polycythemia (PCV), a myeloproliferative neoplasm characterized by an increase in red blood cells, may be present in asymptomatic patients with pre-existing conditions such as thrombotic thrombocytopenic purpura (TTP).
A study published in Clinical Case Reports describes the case of newly diagnosed PCV occurring within 1 month of a relapsed TTP episode with concurrent undiagnosed rheumatoid arthritis (RA). A 63-year-old African American male with a past history of transient ischemic attack (TIA), chronic joint pain, and thrombocytopenia, presented with a 3-week history of weakness, confusion, intractable lower extremity stiffness, fever, and easy bruising.
Examinations revealed the patient had severe anemia, thrombocytopenia, hyperbilirubinemia, and elevated creatinine and lactate dehydrogenase (LDH). A direct antiglobulin test turned out negative for autoimmune hemolytic anemia. As the patient presented with classic symptoms of TTP, ADAMTS13 activity was measured and the diagnosis of TTP, suspected to have been acquired from concomitant rheumatologic/autoimmune disease, was made.
The patient was treated with daily 1-volume plasma exchange (PEX) and steroid therapy and achieved normalization of hematocrit, platelet count, LDH, and ADAMTS13 activity after 9 sessions. Upon referral to a rheumatologist, seropositive RA was diagnosed.
At a follow-up 2 weeks after discharge, the patient was asymptomatic without any physical or hematologic abnormalities, but presented with hematocrit levels elevated at 55.6%. Two weeks later, the patient’s hematocrit levels continued to rise despite normal erythropoietin (EPO) levels, reaching 56.5%; yet the patient remained asymptomatic.
Primary polycythemia and secondary polycythemia were considered as differential diagnoses due to the regular EPO levels, and a bone marrow (BM) biopsy discovered the JAK2 V617F mutation, a defining feature found in more than 90% of patients with PCV.
Due to the elevated risk of a thrombotic event owing to the diagnosis of PCV and history of relapsing TTP, TIA, and advanced age, the patient was started on daily low-dose aspirin, and weekly phlebotomy sessions were planned in conjunction with hydroxyurea 500 mg cytoreductive therapy.
The patient was followed up on a weekly basis, and after 4 weeks achieved a normalization of hematocrit, platelet, and WBC counts. The patient was treated with PEX and high-dose steroids plus a 4-week course of rituximab 375 mg/m2 once a week for his TTP, and reached normal levels.
As reflected in this case, a complicated history and various confounding factors may require specific criteria be met to diagnose PCV, including hematocrit levels greater than 52% in men, the presence of JAK2 V617F or other similar mutations, plus either a BM biopsy showing hypercellularity for age with trilineage growth of prominent erythroid, granulocytic, and megakaryocytic proliferation, or subnormal serum EPO levels.
These investigators were able to diagnose PCV due to identifying the JAK2 V617F mutation and erythroid hyperplasia on BM biopsy despite the normal EPO level.
The authors of the study concluded that the case “reflects the growing need for a more comprehensive risk assessment of thrombosis in patients with PCV, even more so in patients with concomitant conditions that predispose to thrombosis including autoimmune disorders.”
1. Hassan OA, Moey MYY, Papageorgiou CN. From anemia to polycythemia in 4 weeks [published online August 3, 2017]. Clin Case Rep. doi: 10.1002/ccr3.879