A 64-year-old man comes to the office due to progressive fatigue and weakness over the past several months. The patient says, "I have very little energy and can hardly walk a block without resting." He has had no chest pain, palpitations, or dyspnea at rest but has had mild breathlessness while walking. His wife adds that he has lost his appetite, and she believes that he has lost some weight. The patient was diagnosed with hypertension several years ago but does not take any medications. He drinks a half-pint of whiskey a day. Blood pressure is 148/86 mm Hg, pulse is 80/min, and respirations are 14/min. Oxygen saturation is 98% while breathing ambient air. Lung auscultation is normal and heart sounds are normal with no murmur. The abdomen is nondistended, soft, and nontender on palpation. Rectal examination shows occult blood-positive brown stool. Laboratory results are as follows: Which of the following is the best initial step in evaluation of this patient's anemia?

Question

A 64-year-old man comes to the office due to progressive fatigue and weakness over the past several months.  The patient says, "I have very little energy and can hardly walk a block without resting."  He has had no chest pain, palpitations, or dyspnea at rest but has had mild breathlessness while walking.  His wife adds that he has lost his appetite, and she believes that he has lost some weight.  The patient was diagnosed with hypertension several years ago but does not take any medications.  He drinks a half-pint of whiskey a day.  Blood pressure is 148/86 mm Hg, pulse is 80/min, and respirations are 14/min.  Oxygen saturation is 98% while breathing ambient air.  Lung auscultation is normal and heart sounds are normal with no murmur.  The abdomen is nondistended, soft, and nontender on palpation.  Rectal examination shows occult blood-positive brown stool.  Laboratory results are as follows:  Which of the following is the best initial step in evaluation of this patient's anemia?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c157_a6d2_8f63_67c018c5c8f7_MD0005_00 This patient has microcytic anemia (mean corpuscular volume [MCV] <80 μm³), heme-positive stool on guaiac, weight loss, and fatigue. This constellation of symptoms is highly concerning for iron deficiency anemia most likely associated with occult gastrointestinal (GI) bleeding. The most common cause of iron deficiency anemia in the United States is blood loss, and in a male age >50 with iron deficiency anemia, colon cancer needs to be excluded. This patient's presentation warrants iron studies and a colonoscopy as part of his initial workup. (Choice A) Bone marrow biopsies are useful in evaluating hypoproliferative causes of anemia (eg, aplastic anemia, leukemia, myelodysplasia syndrome). This patient has evidence of a GI bleed as the primary source of his anemia; therefore, a bone marrow biopsy would not be indicated until a GI source is ruled out. (Choice C) Erythropoietin is a growth factor produced by the kidney that stimulates precursors of red blood cells to start production of erythrocytes within the bone marrow. Patients with chronic kidney disease (CKD) and end-stage renal disease frequently have low erythropoietin levels due to kidney dysfunction. Although this patient has evidence of possible CKD (given his creatinine level of 1.9 mg/dL), he has a positive stool guaiac result, indicating probable chronic lower GI bleed; therefore, colon cancer is the most concerning diagnosis and must be ruled out. (Choice D) Esophagogastroduodenoscopy (EGD) is used to evaluate for an upper GI bleed. In this elderly male patient with occult GI bleeding without abdominal pain, colon cancer is the most likely diagnosis. If a colonoscopy is negative, an EGD should be considered to evaluate for a slow-bleeding ulcer. (Choice E) A tagged red blood cell scan is a very sensitive study used to detect acute GI bleeds; however, it requires a rapid bleeding source. This patient has occult GI bleeding, which would likely result in a negative red blood cell scan. Educational objective: Colonoscopy is the initial test of choice in patients with iron-deficiency anemia and positive fecal occult blood test. In patients with no obvious pathologic findings on colonoscopy, upper gastrointestinal endoscopy should be performed. References: Gastrointestinal causes of refractory iron deficiency anemia in patients without gastrointestinal symptoms. (http://www.ncbi.nlm.nih.gov/pubmed/11690568)

A 64-Year-Old Man Comes to the Office Due to Progressive