1.1. ACD is called the anemia of inflammation with mild to moderate symptoms of anemia due to infectious, inflammatory, or neoplastic disease. This process is characterized by numerous reticuloendothelial iron which can't be used as bone marrow erythroid precursors, causing iron-restricted erythropoiesis. This impaired iron usage is triggered by cytokines, lowering the serum iron level and affecting macrophage iron storage to prevent iron uptake. Hepcidin is a main regulator for iron absorption as well as iron efflux from macrophages, controlling the pathogenesis of ACD by decreasing iron absorption in small intestines and blocking iron release from macrophages through the interaction with ferroportin. Hepcidin also causes hypoferremia and anemia. Also, low EPO secretion and impaired EPO responsiveness may contribute to ACD.
2. Diagnosis
2.1. The diagnosis of ACD can be challenging and should rule out other causes of anemia such as blood loss, hemolysis, malnutrition, folate or vitamin B12 deficiency, and myelodysplastic syndrome. Bone marrow biopsy can be done for diagnosis of ACD. Laboratory findings of ACD include mild enemia with normocytic or slightly microcytic indices, low serum iron, decreased TIBC (transferrin) levels, and increased ferritin levels, indicating an increase in iron stores. Patients with the combination of iron deficiency and an infectious, inflammatory, or malignant disorder can utilize the TFR-ferritin index for diagnosis of ACD because transferrin receptor (TFR) is not increased with infection or inflammation.
3. Signs and Symptoms
3.1. ACD's symptoms can vary in severity from a patient to another. Usual symptoms include fatigue, pallor, chest pain, dizziness, shortness of breath, tachycardia, irritability, and others.
4. Treatments
4.1. Usually, the symptoms may go away as the underlying inflammation process disappears or as the compensatory mechanisms kick in. In many case, patients' symptoms are mild or asymptomatic, which do not require other treatments. However, transfusions can be given for the immediate correction of anemia. The use of recombinant human EPO therapy such as epoetin alfa (Epogen, Procrit) and darbepoetin alfa (Aranesp) is to minimize transfusion needs.
5. Causes
5.1. The exact cause of ACD is uncertain; however, the underlying medical conditions such as cancer or infection may affect the progress. The common causes of ACD include impaired production of red blood cells (erythropoiesis) or erythropoietin (a hormone that stimulates red blood cell production). Also, infiltration of the bone marrow by cancer cells may cause ACD. In addition, imbalance of iron distribution related to chronic diseases can contribute to ACD. Cytokines as well as hepcidin also play important roles in the development of ACD.
