Anemia of Chronic Disease (Anemia of Inflammation)

Basics

Anemia that accompanies a variety of systemic diseases, with the common features of chronicity and inflammation
Anemia of chronic disease is more properly called anemia of inflammation (AI) and is the combined result of mildly increased destruction of RBCs, relative erythropoietin resistance, and iron-restricted erythropoiesis.

Typically mild to moderate anemia (Hgb 7 to 12 g/dL); develops in the setting of infection, inflammatory disorders, and some malignancies

Deficient cellular iron in the setting of hepcidin excess (functionally inaccessible iron)
Typically normochromic, normocytic but, if long-standing, can be hypochromic, microcytic (especially in children)
Main mechanism appears to be
- Hepcidin is increased by interleukin-6 (IL-6), causing depletion of ferroportin, the only known membrane iron transporter.
- Elevated hepcidin results in macrophage inability to release iron recycled from senescent RBCs, hepatocyte inability to release stored iron, and enterocyte inability to absorb dietary iron.
- These changes lead to iron restriction with decreased iron available for erythropoiesis.
Other factors contributing to anemia in various degrees include the following:
- Increased red cell destruction
- Diagnostic phlebotomy or other blood loss
- Inflammatory cytokines suppress erythropoiesis
- Cytokine-mediated suppression of erythropoiesis
- Cytokines such as interleukin-1 (IL-1) and IL-6 can activate ferritin synthesis, leading to sequestration of iron, which eventually is converted into hemosiderin.

Underlying disease process

Underlying disease process
- Infections, both acute and chronic
- Inflammatory disease
- Collagen vascular diseases
- Malignancies
- Renal failure
Anemia of chronic disease often coexists with other causes of anemia, including:
- Occult blood loss
- Hemolysis
- Dietary iron deficiency
- Drug-related marrow suppression

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