A 63-year-old man comes to the physician complaining of easy fatigability. He has a history of hypertension treated with lisinopril. Over the last 3 months, he has had right knee pain due to osteoarthritis and has taken naproxen for pain relief. His blood pressure is 123/78 mm Hg and heart rate is 78/min. His right knee is mildly deformed due to bony overgrowth but is not tender or swollen. Physical examination is otherwise normal. Laboratory results are as follows: Which of the following changes would you expect most in this patient?

Question

A 63-year-old man comes to the physician complaining of easy fatigability. He has a history of hypertension treated with lisinopril. Over the last 3 months, he has had right knee pain due to osteoarthritis and has taken naproxen for pain relief. His blood pressure is 123/78 mm Hg and heart rate is 78/min. His right knee is mildly deformed due to bony overgrowth but is not tender or swollen. Physical examination is otherwise normal. Laboratory results are as follows:

Which of the following changes would you expect most in this patient?

Quizplus · Accepted Answer

11ec25c8_d41f_986f_bc81_8db0fd755755_MD0003_00 This patient has a significant microcytic anemia, which is the likely cause of his fatigue. Common causes of microcytic anemia include iron deficiency, anemia of chronic disease (ACD), and thalassemia. His recent naproxen use places him at risk for peptic ulcers/gastritis leading to chronic blood loss from the gastrointestinal tract and resulting iron depletion. Iron studies can be used to confirm the diagnosis of iron deficiency anemia. In addition to low serum iron, serum ferritin is also usually low because it reflects the body's total iron stores. The level of transferrin, as measured by the total iron-binding capacity (TIBC), is increased in iron deficiency as there is typically an inverse relationship with serum iron. The transferrin saturation (serum iron/TIBC) is low given the low serum iron and elevated TIBC. (Choice A) Anemia of chronic disease (ie, anemia of chronic inflammation) is due to suppression of red blood cell production by inflammatory cytokines. Iron studies will typically show a low serum iron, low TIBC (transferrin) with relatively normal (or mildly low) transferrin saturation. Ferritin may be elevated in ACD as it is an acute phase reactant and is mobilized in many inflammatory conditions. Osteoarthritis, as in this patient, does not involve a significant release of inflammatory cytokines and would not cause ACD. (Choice C) This combination of markers is rare as low TIBC with high transferrin saturation would not often be seen with low serum iron. (Choice D) An elevated serum iron, ferritin, and transferrin saturation with low TIBC would suggest iron overload, as in hemochromatosis. Patients receiving frequent transfusions for anemia related to hemoglobinopathies may also develop iron overload, but this would not be seen in a newly diagnosed patient. It is also unlikely that a significant thalassemia or other hemoglobinopathy would not be diagnosed until age 63. (Choice E) Given this patient's significant microcytic anemia, his iron studies would not likely be entirely normal regardless of the diagnosis. Educational objective: The most common causes of microcytic anemia include iron deficiency, anemia of chronic disease, and thalassemia. Iron studies can be used to differentiate among these etiologies. Iron deficiency anemia usually demonstrates a low serum iron, low ferritin, elevated total iron-binding capacity (TIBC), and low transferrin saturation (ie, iron/TIBC). Iron deficiency in men is usually due to chronic gastrointestinal blood loss. References: Iron deficiency anaemia: a review of diagnosis, investigation and management. (http://www.ncbi.nlm.nih.gov/pubmed/22157204)

A 63-Year-Old Man Comes to the Physician Complaining of Easy