Anemia secondary to low erythropoietin in a patient with normal renal function

Anemia with a relatively low erythropoietin level has been described in several medical conditions associated with chronic inflammatory diseases such as rheumatoid arthritis, cancer, sickle cell disease, chronic renal failure, acquired immunodeficiency syndrome, and severe autonomic nervous system failure. This case report describes the development of anemia with a relatively low erythropoietin level in a 65-year-old man with non-insulin-dependent diabetes mellitus, normal renal function, and negative hematologic, thyroid, and autoimmune disease work-ups. The serum erythropoietin level was 14 mU/mL (N: 10-20 mU/mL). The hemoglobin was 7.5 g/dL and the hematocrit was 24%. The patient was treated with recombinant erythropoietin at 50 U/kg subcutaneously three times weekly. The hemoglobin level increased over a 4-week period. When erythropoietin was stopped, the anemia recurred in 2 months. We conclude that the patient's anemia was caused by a relative lack of endogenous erythropoietin release. The exact mechanism of this anemia is unknown. We recommend including a test for erythropoietin level in the evaluation of any unexplained anemia.