What is the management plan for a patient with erythrocytosis?

Management of Erythrocytosis

The management of erythrocytosis should focus on treating the underlying cause while avoiding routine phlebotomies, as these can lead to iron deficiency and increased risk of stroke. 1

Initial Assessment

• Confirm true erythrocytosis: elevated hemoglobin (>16.5 g/dL in men, >16 g/dL in women) and hematocrit (>49% in men, >48% in women)
• In this case: Hemoglobin 18.4 g/dL (H), Hematocrit 53.9% (H), RBC 6.03 x10^6/μL (H)
• Measure serum erythropoietin (EPO) level to differentiate between primary and secondary causes:
  • Low EPO: Primary erythrocytosis (e.g., polycythemia vera)
  • Normal/elevated EPO: Secondary erythrocytosis

Diagnostic Workup

1. Rule out secondary causes:

   • Cardiopulmonary disease (cyanotic congenital heart disease, chronic obstructive pulmonary disease)
   • High altitude exposure
   • Smoking
   • Sleep apnea
   • Renal disease (renal cell carcinoma, renal cysts, post-transplant)
   • Hepatic tumors (hepatocellular carcinoma, adenoma)
   • Exogenous EPO use

2. Laboratory tests:

   • Complete blood count with differential
   • Iron studies (ferritin, transferrin saturation)
   • Renal and liver function tests
   • JAK2 mutation testing (if primary erythrocytosis suspected)

Management Principles

For Secondary Erythrocytosis

1. Treat the underlying cause when possible 1

2. Hydration:

   • Ensure adequate hydration to reduce blood viscosity
   • Avoid dehydration, especially during air travel or hot weather 1

3. Therapeutic phlebotomy:

   • Indications: Hemoglobin >20 g/dL and hematocrit >65% WITH symptoms of hyperviscosity (headache, fatigue, visual disturbances) 1
   • Procedure: Remove 400-500 mL of blood with isovolumic replacement (750-1000 mL of isotonic saline) 1
   • Caution: Avoid routine phlebotomies as they can lead to iron deficiency, which paradoxically increases risk of thrombosis 1

4. Iron supplementation:

   • Provide iron supplementation if iron deficiency is present (MCV <80 fL) 1
   • Monitor carefully due to potential rebound effect on erythropoiesis 1

5. Antiplatelet therapy:

   • Consider low-dose aspirin in patients with additional cardiovascular risk factors
   • Use with caution due to increased bleeding risk in cyanotic patients 1

For Cyanotic Congenital Heart Disease with Erythrocytosis

1. Avoid routine phlebotomies - these can lead to iron deficiency and paradoxically increase thrombotic risk 1

2. Maintain iron repletion - iron deficiency in cyanotic patients can lead to microcytosis, which increases blood viscosity and risk of stroke 1

3. Pulmonary vasodilator therapy may be beneficial for patients with Eisenmenger physiology 1

Special Considerations

• Pregnancy: High-risk in patients with cyanotic heart disease and erythrocytosis; should be avoided 1

• Surgery: Requires careful planning with a multidisciplinary team; maintain euvolemia and avoid hypotension 1

• Air travel: Maintain hydration with non-alcoholic, non-caffeinated fluids 1

Monitoring

• Regular follow-up every 6-12 months
• Monitor complete blood count, iron studies, renal function
• Assess for symptoms of hyperviscosity
• Evaluate for complications related to the underlying condition

Common Pitfalls to Avoid

• Inappropriate phlebotomy: Routine phlebotomy without proper indication can lead to iron deficiency, which increases risk of stroke 1

• Neglecting iron status: Iron deficiency in erythrocytosis can cause microcytosis and paradoxically increase blood viscosity 1

• Confusing primary and secondary erythrocytosis: Treatment approaches differ significantly; accurate diagnosis is essential 2

• Overlooking underlying causes: Always investigate for potentially treatable underlying conditions 3