Management of Erythrocytosis with Thrombocytosis in a Smoker
This patient requires immediate smoking cessation as the priority intervention, combined with evaluation for a myeloproliferative neoplasm given the constellation of elevated RBC count, low MCH, and marked thrombocytosis. 1, 2
Immediate Diagnostic Priorities
Distinguish between smoking-induced secondary erythrocytosis versus essential thrombocythemia (ET) or polycythemia vera (PV). The combination of erythrocytosis AND thrombocytosis (platelet count 537 × 10⁹/L) raises concern for a myeloproliferative neoplasm rather than simple smoking-related polycythemia. 3, 4
Key Diagnostic Steps:
Measure JAK2V617F mutation status immediately - present in ~55% of ET patients and nearly all PV patients; its absence combined with normal/elevated erythropoietin makes PV unlikely. 3, 4
Check serum erythropoietin level - typically low or low-normal in PV, elevated in secondary erythrocytosis from smoking. 2, 3
Obtain carboxyhemoglobin level - smoking causes elevated carboxyhemoglobin sufficient to produce clinically significant hypoxemia and secondary erythrocytosis. 5
Assess iron status with ferritin and transferrin saturation - the low MCH (23.6) suggests possible iron deficiency, which can mask the full extent of erythrocytosis. 1, 2
Perform peripheral blood smear to evaluate red cell morphology and confirm thrombocytosis. 2
Smoking Cessation: The Critical First Intervention
All patients must be aggressively counseled to stop smoking immediately. 6
Evidence-Based Cessation Strategy:
Offer pharmacological support with nicotine replacement therapy, bupropion, or varenicline - these achieve 1-year cessation rates of 16-30% versus 5% with physician advice alone. 6
Smoking directly causes erythrocytosis through carboxyhemoglobin-induced tissue hypoxemia, which is reversible upon cessation. 5
Smoking cessation can normalize elevated blood counts - documented cases show resolution of chronic neutrophilia and improvement in erythrocytosis within months of quitting. 5, 7
Avoid e-cigarettes as a cessation tool - they are not harm-free and cause negative vascular endothelial changes; only consider alongside formal cessation programs. 6
Management Based on Underlying Diagnosis
If Myeloproliferative Neoplasm (ET or PV) is Confirmed:
Risk stratification determines treatment intensity:
High-risk criteria: Age >60 years OR prior thrombosis history OR JAK2/MPL mutation with age >60 in ET. 6, 3
Platelet count >1,500 × 10⁹/L is a bleeding risk requiring cytoreductive therapy regardless of other risk factors. 6
For High-Risk Patients:
Hydroxyurea is first-line cytoreductive therapy at any age, though use in patients <40 years requires careful consideration. 6, 3
Low-dose aspirin (81 mg daily) reduces thrombotic complications unless contraindicated by bleeding risk. 6, 3
Screen for acquired von Willebrand syndrome before starting aspirin if platelets >1,000 × 10⁹/L. 3, 4
For Low-Risk Patients:
Low-dose aspirin alone may be sufficient for ET patients without additional risk factors. 6, 3
Phlebotomy to maintain hematocrit <45% is essential in PV to reduce thrombotic events. 6, 3
If Secondary Erythrocytosis from Smoking:
Ensure adequate hydration as first-line therapy for all patients with erythrocytosis. 1, 2
Avoid routine phlebotomy unless hemoglobin >20 g/dL AND hematocrit >65% with hyperviscosity symptoms (headache, visual disturbances, fatigue, poor concentration). 1, 2
Phlebotomy protocol when indicated: Remove 1 unit (400-500 mL) with simultaneous equal volume replacement using isotonic saline to maintain intravascular volume. 1
Repeated phlebotomies risk iron depletion, which paradoxically worsens symptoms by reducing oxygen-carrying capacity and increasing stroke risk. 1, 2
Critical Pitfalls to Avoid
Do not perform routine phlebotomies without meeting strict criteria (Hgb >20 g/dL, Hct >65%, symptomatic hyperviscosity) - this creates iron deficiency that worsens outcomes. 1, 2
Do not assume smoking alone explains thrombocytosis - smokers' polycythemia does not typically cause platelet elevation; concurrent thrombocytosis suggests ET. 3, 8
Recognize that smokers' polycythemia has lower thrombotic risk than PV (41% vs 60% incidence), but still requires aggressive cardiovascular risk factor management. 8
Iron deficiency can mask erythrocytosis severity - the low MCH (23.6) indicates this patient may have more significant erythrocytosis than apparent; cautious iron supplementation with close hemoglobin monitoring may be needed. 1, 2
Monitoring Strategy
Regular complete blood counts to track hemoglobin, hematocrit, and platelet response to interventions. 1, 2
Periodic iron status assessment to prevent deficiency from phlebotomy or detect deficiency masking disease severity. 1, 2
Monitor for hyperviscosity symptoms (headache, visual changes, fatigue) and thrombotic complications. 1, 2
Assess cardiovascular risk factors aggressively - hypertension, diabetes, hyperlipidemia all compound thrombotic risk. 6