Copper deficiency is a rare disease because of the ubiquitous distribution of copper and low daily requirements. Copper deficiency has been reported in patients who receive total parenteral nutrition [1], who have the short-bowel syndrome [2], and who receive oral zinc therapy [3] and in premature infants [4]. We describe a patient who developed copper deficiency anemia after long-term enteral feeding.

A 77-year-old woman was hospitalized in July 1993 because of severe macrocytic anemia. She had an erythrocyte count of 110 x 10⁴/µL, a hemoglobin level of 4.4 g/dL, a hematocrit of 12.8%, and a mean corpuscular volume of 116.4 fL. She also had neutropenia, with a leukocyte count of 3.1 x 10³/µL (45% neutrophils). In November 1990, she had become bedridden because of a brain stem hemorrhage and received forced enteral feeding at her home. The administered commercial diet contained 0.048 mg of copper daily. Repeated examinations of the stool for occult blood were negative. Serum levels of folic acid, vitamin B₁₂, vitamin B₆, vitamin C, and iron were normal. The serum level of copper was 6 µg/dL (normal, 70 to 135 µg/dL), and the ceruloplasmin level was 9 mg/dL (normal, 18 to 37 mg/dL). Bone marrow aspiration showed cytoplasmic vacuolization in the erythroid cell lines (Figure 1). Intravenous administration of 1.25 mg of CuSO₄ (equivalent to 5 µmol of copper) daily led to the improvement of the anemia and neutropenia, confirming the diagnosis of copper deficiency anemia.

View larger version (163K): [in this window] [in a new window]   Figure 1. Bone marrow findings in the patient before copper administration. Cytoplasmic vacuolization of the erythroblast is present. (May-Grunwald-Giemsa stain, magnification x 100).

The dietary intake of copper recommended by the American Medical Association is 1.21 to 1.28 mg/d in adults [5]. Although to our knowledge copper deficiency anemia caused by long-term forced enteral feeding in adults has never been described previously, inadequate diet alone does cause copper deficiency. Clinicians should be aware of the existence of copper deficiency anemia in patients receiving prolonged forced enteral feeding.