Diagnosis and management of iron-related anemias in critical illness.

OBJECTIVE: To review of the prevalence, pathogenesis, diagnosis, and management of iron (Fe)-related anemias in critical illness. DATA SOURCE: A MEDLINE/PubMed search from 1966 to October 2005 was conducted. References from relevant articles were manually cross-referenced with additional original articles, review articles, correspondence, and chapters from selected textbooks. DATA EXTRACTION AND SYNTHESIS: Both Fe metabolism and erythropoiesis are affected by the inflammatory response that accompanies critical illness. As a result, many critically ill patients develop the anemia of inflammation, which may be compounded by an underlying Fe deficiency. Most commonly available markers of total body Fe detect Fe deficiency unreliably in the setting of inflammation. Among these tests, the serum transferrin receptor assay is relatively accurate in reflecting total body Fe, regardless of inflammation. Treatment options for Fe-related anemias in critical illness include Fe replacement and recombinant human erythropoietin therapy. The decision to implement these therapies is complex and centers on a critical evaluation of ability to affect anemia, morbidity, and mortality in critical illness and on the potential risks of therapy.
CONCLUSIONS: Fe deficiency anemia and the anemia of inflammation may co-exist in critical illness. Diagnosis of and differentiation between these two anemias involves careful interpretation of multiple markers of total body Fe stores. The utility of treatment with both Fe and recombinant human erythropoietin for these disorders during critical illness requires further investigation.