DESCRIPTION

• Anemia of chronic disease is also known as anemia of inflammation (AI) and occurs with both acute and chronic immune activation. It often accompanies a variety of systemic diseases and chronic illnesses.
• It is an immune-driven process characterized by changes in iron homeostasis and effects on hepcidin.

PATHOPHYSIOLOGY

Typically mild to moderate anemia (hemoglobin [Hgb] 7 to 12 g/dL); develops in the setting of systemic inflammatory disorders, infections, malignancies, and chronic disorders

• Primary mechanisms include the following:
  • Dysregulation of iron homeostasis with effects on hepcidin and cytokines whereby the increase in hepcidin and other cytokines causes iron to be retained in the cells of the reticuloendothelial system and unavailable for red blood cell (RBC) production
  • Impaired proliferation of erythroid progenitor cells
  • Blunted erythropoietin (EPO) response
• Other factors contributing to anemia in various degrees include the following:
  • Increased red cell destruction
  • Diagnostic phlebotomy or other blood loss
  • Inflammatory cytokines suppressing 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.

COMMONLY ASSOCIATED CONDITIONS

• Underlying disease process
  • Acute and chronic infections
  • Autoimmune disorders (i.e., rheumatoid arthritis, systemic lupus erythematosus, vasculitis, inflammatory bowel disease)
  • Hematologic and solid tumor malignancies
  • Chronic kidney disease
  • Chronic rejection after solid-organ transplant
• Anemia of chronic disease often coexists with other causes of anemia, including the following:
  • Occult blood loss
  • Hemolysis
  • Dietary iron deficiency
  • Drug-related marrow suppression