Management of Crohn's Disease and Microcytic Anemia
In a 20-year-old female patient with small-bowel Crohn's disease with mild microcytic anemia and low serum ferritin, is it reasonable to treat with a total dose infusion of parenteral iron if she is unable to tolerate oral iron? How often can this be repeated if the problem recurs?

Both anemia of iron deficiency (as a result of inadequate intake or loss) and anemia of chronic disease (secondary to decreased erythropoiesis, secondary to increased levels of proinflammatory cytokines, reactive oxygen metabolites, and nitric oxide) are frequently encountered in inflammatory bowel disease (IBD). Hemolytic anemia may, on rare occasions, be associated with IBD. A definitive diagnosis must be made prior to iron therapy and this may warrant a bone marrow trephine.

Unfortunately, assessment of the iron status in a condition associated with inflammation, such as IBD, is difficult. The combination of serum transferrin receptor with ferritin concentrations, however, allows a reliable assessment of the iron deficit. Furthermore, serum erythropoietin and transferrin concentrations have the potential to predict the response to iron sucrose therapy in IBD-associated anemia. These parameters may help to identify individuals who benefit the most from additional erythropoietin treatment.

The best therapy for anemia of chronic disease is the cure of the underlying disease. Erythropoietin, together with iron supplementation, improves this anemia when combined with adequate disease control. It is important to note that iron supplementation may lead to an increased inflammatory activity through the generation of reactive oxygen species, although this has only been shown in animal studies.

Total dose intravenous infusion of iron dextran, when appropriately used, is a safe and potentially efficacious treatment with IBD and iron deficiency anemia patients who are unresponsive to, or noncompliant with, oral iron therapy.

Depending on the response to therapy, the infusions can be repeated on a monthly basis. It is essential, however, to monitor the response and be ever aware of the potential of iron overload.