A 58-year-old woman with a 10-year history of severe rheumatoid arthritis presents to the … — USMLE Step 2 CK

A 58-year-old woman with a 10-year history of severe rheumatoid arthritis presents to the clinic with worsening fatigue over the past few months. Her joint pain has also been poorly controlled recently despite her current medication regimen. Vital signs are within normal limits. Physical examination reveals swollen, tender metacarpophalangeal and proximal interphalangeal joints bilaterally.

Laboratory studies show the following:

Laboratory Test	Result	Reference Range
Hemoglobin	10.1 g/dL	12.0 - 15.5 g/dL
Mean corpuscular volume	76 fL	80 - 100 fL
Serum iron	35 $\mu$ g/dL	60 - 160 $\mu$ g/dL
Total iron-binding capacity (TIBC)	210 $\mu$ g/dL	250 - 460 $\mu$ g/dL
Serum ferritin	520 ng/mL	15 - 200 ng/mL

Which of the following is the most appropriate next step in the management of this patient's anemia?

A
Administration of recombinant erythropoietin
B
Transfusion of packed red blood cells
C
Oral ferrous sulfate supplementation
Optimization of rheumatoid arthritis therapyAnswer
E
Intravenous iron dextran infusion

Answer

Optimization of rheumatoid arthritis therapy

The correct answer addresses the underlying pathophysiology of this patient's condition. The patient presents with microcytic anemia and an iron profile that is classic for anemia of chronic disease (low serum iron, low TIBC, elevated ferritin). Chronic inflammation from poorly controlled rheumatoid arthritis increases the production of hepcidin in the liver. Hepcidin binds and degrades ferroportin, trapping iron inside macrophages and enterocytes. This makes iron unavailable for red blood cell production despite adequate total body stores. The definitive management for anemia of chronic disease is to treat the underlying inflammatory disease, which will subsequently lower hepcidin levels, release sequestered iron, and improve the anemia.

Step-by-Step Solution

Analyze the patient's complete blood count and iron panel.

The patient has a microcytic anemia with low serum iron, low total iron-binding capacity (TIBC), and elevated serum ferritin.

To differentiate between the causes of microcytic anemia, which primarily include iron deficiency anemia, anemia of chronic disease, and thalassemia.

Synthesize the laboratory findings with the clinical history.

The high ferritin and low TIBC in the setting of poorly controlled rheumatoid arthritis points definitively to anemia of chronic disease (also known as anemia of inflammation).

Inflammation upregulates hepcidin, leading to iron sequestration in macrophages (causing high ferritin) and decreased iron absorption, resulting in low serum iron and low TIBC.

Determine the best management for anemia of chronic disease.

The primary treatment is addressing the underlying inflammatory condition.

Treating the underlying rheumatoid arthritis will reduce inflammatory cytokines, decrease hepcidin levels, and restore normal iron metabolism for erythropoiesis.

Key Concept

Anemia of chronic disease (anemia of inflammation) is characterized by low serum iron, low TIBC, and normal or elevated ferritin. The definitive treatment is managing the underlying inflammatory disorder.

Estimated Time:1m 0s

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