ANEMIA OF CHRONIC DISEASE
The term “anemia of chronic disease” is a misnomer in that only the chronic diseases of inflammation, infection, and malignancy cause this type of anemia. Many chronic inflammatory diseases are associated with a normochromic, normocytic anemia (ie, the RBCs are normal in color and size). These disorders include rheumatoid arthritis; severe, chronic infections; and many cancers. It is therefore imperative that the “chronic disease” be diagnosed when this form of anemia is identified so that it can be appropri-ately managed.
The anemia is usually mild to moderate and nonprogressive. It develops gradually over 6 to 8 weeks and then stabilizes at a hematocrit seldom less than 25%. The hemoglobin level rarely falls below 9 g/dL, and the bone marrow has normal cellularity with increased stores of iron as the iron is diverted from the serum (and thus is unavailable as a growth factor for invading pathogens). Erythropoietin levels are low, perhaps because of decreased pro-duction, and iron use is blocked by erythroid cells (cells that are or will become mature RBCs). A moderate shortening of RBC sur-vival also occurs.
Most of these patients have few symptoms and do not require treatment for the anemia. With successful treatment of the un-derlying disorder, the bone marrow iron is used to make RBCs and the hemoglobin level rises.