Phlebotomy with iron therapy to correct the microcytic polycythemia of chronic hypoxia.

Patients with chronic hypoxia develop a physiologically appropriate "secondary" polycythemia that improves oxygen carrying capacity. Supplemental iron is often required to maintain this. In severe cases when hematocrit levels approach 70%, iron is withheld in order to avoid dangerously high hematocrit levels and the risks of vascular sludging due to "hyperviscosity." Some patients even require reduction of viscosity by exchange of their polycythemic blood for plasma when symptoms develop. Iron deficiency with microcytic polycythemia can then develop. Management of such patients is unclear. Continued blood withdrawal will worsen the iron deficiency; iron supplementation will increase the hematocrit level and the risks of hyperviscosity. The combination of frequent phlebotomy with oral iron therapy should improve iron stores while safely maintaining a stable hematocrit level in patients with microcytic polycythemia. This combination should also have multiple beneficial effects on tissue oxygen delivery and utilization. This approach has been discussed and used for a patient with microcytic polycythemia due to Eisenmenger syndrome. While on therapy the patient's clinical symptoms decreased, and his serum iron level, hematologic indices, and treadmill tolerance tests all improved.