Anemia in patients with rheumatoid arthritis often manifests as normocytic normochromic anemia, with hemoglobin (HGB) typically around 10-11 g/L. The cause is usually anemia of chronic disease or inflammatory anemia. Controlling inflammation and using antirheumatic drugs to treat rheumatoid arthritis can alleviate the anemia. Additionally, anemia may present as:
(1) Iron deficiency anemia - microcytic hypochromic anemia: Nonsteroidal anti-inflammatory drugs can cause gastrointestinal bleeding, leading to microcytic hypochromic anemia. Patients with rheumatoid arthritis are more prone to deficiencies in folic acid and vitamin B12, although the exact cause is unclear.
(2) Hemolytic anemia - normocytic normochromic anemia: This is mainly seen as a complication in patients with rheumatoid arthritis. Felty’s syndrome patients present with splenomegaly, neutropenia, anemia, and thrombocytopenia. (Platelet counts can increase during active phases of rheumatoid arthritis.)
(3) Drug-induced bone marrow suppression - macrocytic anemia: Methotrexate, leflunomide, sulfasalazine, azathioprine, and cyclophosphamide can cause macrocytic anemia.