Case study (41) - Anemia of Rheumatoid Arthritis.
A 56-year-old woman with long-standing arthritis and abnormal blood counts:
Hemoglobin (Hb) 91 g/L
Mean corpuscular volume (MCV) 91 g/L
Mean corpuscular hemoglobin volume (MCHC) 32.1
White blood cells (WBC) 7.2 X 109/L
Platelets 195 X 109/L
Questions:
Q1. What diagnosis is suggested by the x-ray of her hands?
Q2. What is the likeliest cause of her anemia?
Q3. What investigations would you perform on this patient?
Q4. What other hematological complications may occur in this condition?
Answers:
A1. The x-ray confirms the diagnosis of rheumatoid arthritis – it shows erosive arthritis affecting her hands.
A2. The anemia of chronic disease (ACD). This normochromic normocytic (occasionally slightly microcytic) anemia commonly complicates chronic inflammatory and infective conditions and neoplasia.
The mechanism is poorly understood, but it may involve inhibition and increase cytokine levels (e.g., tumor necrosis factor [TNF], interleukin 6) have on erythropoiesis, the release of iron from the reticuloendothelial system, and iron utilization.
A3. The diagnosis of rheumatoid can be confirmed by displaying the presence of rheumatoid factor and anti-cyclic citrullinate peptide (anti-CCP) antibodies.
Disease-modifying treatments for rheumatoid include monoclonal antibodies to TNF, and these agents may improve the anemia.
In ACD, the serum iron and the total iron-binding capacity are usually reduced Serum ferritin is usually normal, although it may increase in the face of active inflammation.
A decrease in serum ferritin indicates an iron deficiency, Often complicates rheumatoid arthritis (e.g., due to gastric bleeding induced by ingestion of non-steroidal anti-inflammatory drugs).
Vitamin B12 and folic acid levels, thyroid function, kidney function, liver function, and erythrocyte sedimentation rate (ESR) are worthy of evaluation.
A4. Other hematological complications of rheumatoid arthritis include:
- Immunological disorders – autoimmune hemolytic anemia, idiopathic thrombocytopenic purpura, leukopenia, Felty’s syndrome (leukopenia and splenomegaly)
- Therapy-induced complications – gastrointestinal bleeding, cytopenias, aplastic anemia (caused, e.g., by phenylbutazone); the blood film shows a fragment of a bone marrow aspirate taken from a patient with phenylbutazone-induced aplastic anemia
- An increased incidence of lymphoma
- Amyloidosis
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