Question of the Day

A 55 y/o M with h/o of CKD 4 due to diabetic nephropathy has been on tri-weekly EPO for the last 6 weeks for anemia of CKD is found to still have a hemoglobin of 9.2.  He denies any obvious bleeding but reports being hospitalized twice in the last 3 months for diabetic ulcers and IV antibiotics for osteomyelitis of the R foot. His MCV is 87. Retic count 0.9%, ferritin 510, Tsat 30%, Platlets 250K, WBC 9.9. Folate, B12, Carnitine, and peripheral smear are all within normal limits. What is the cause of his decreased response to ESA (erythopoetin stimulating agents)?
A.) The primary cause is overt iron deficiency.
B.) Hif1-alpha deficiency due chronic inflammation due to osteomyletitis.
C.) Carnitine deficiency
D.) Increased hepcidin secondary to chronic inflammation due to osteomyletitis.
Explanation
Hepcidin, a mediator of iron metabolism, has increased release in inflammation and blocks iron absorption from the gut and promotes iron sequestration in macrophages.  It does this by down-regulating ferroportin iron transporter in GI tract (enterocyte) decreasing reabsoprtion and decreasing transport out of macrophages.