Hematology: Polycythemia Vera and ESR

Polycythemia Vera (PV)

• PV is a panmyelosis, excessive proliferation of RBCs, megakaryocytes, and granulocytes
• Manifests with erythrocytosis, leukocytosis, and thrombocytosis
• Most patients (90%-97%) have a JAK2V617 mutation
• Treatment of choice is therapeutic phlebotomy to maintain hematocrit below 45%

Erythrocyte Sedimentation Rate (ESR)

• ESR measures the rate of RBCs settling to the bottom of a tube
• Used to detect and monitor inflammatory conditions, like rheumatoid arthritis
• Ordered with other tests to diagnose and monitor inflammatory conditions
• Low ESR values may occur in sickle cell disease (SCD) during a painless crisis, while ESR increases after pain starts.
• ESR increases within one week of SCD crisis
• High ESRs (>28 mm/hr) associated with poorer prognosis in stroke patients
• ESR is greater than or equal to 37 mm/hr associated with a higher risk of prostate cancer progressing
• High ESR (>22 mm/hr in white men) linked to higher risk of coronary artery disease (CAD)
• ESR values greater than or equal to 100 mm/hr in patients with cancer frequently indicates metastases.
• High ESRs are common in active inflammatory diseases (e.g., rheumatoid arthritis, infections, collagen diseases).
• ESR has low specificity and sensitivity, not suitable for screening; prone to technical errors

ESR in Specific Conditions

• Sickle cell disease (SCD): Low ESR during painless crises; increases after crisis onset.
• Osteomyelitis: Elevated ESR
• Stroke: ESR of >28 mm/h, poorer prognosis
• Prostate cancer: ESR ≥ 37 mm/h, higher incidence of disease progression and death
• Coronary artery disease: Elevated ESR associated with a CAD risk(s) in white men
• Cancer: High ESR (> 100 mm/hr), often associated with the presence of metastases
• **Polymyalgia rheumatica/Temporal arteritis:**High ESR (typically exceeding 90mm/hr)