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A 68-year-old man comes to the clinic because of progressive dyspnea on exertion (DOE) and shortness of breath over the last 7 months. He denies chest pain, orthopnea, or paroxysmal nocturnal dyspnea. His past medical history is significant only for mild osteoarthritis and an episode of pneumonia 20 years ago. His temperature is 37 C (98.6 F), blood pressure is 128/76 mm Hg, pulse is 98/min, respirations are 18/min, and oxygen saturation is 98%. His lungs are clear to auscultation and his heart is slightly tachycardic with no murmurs, rubs, or gallops. His abdomen is soft, nontender, with normal bowel sounds. His extremities have no edema. Rectal examination shows brown guaiac-positive stool. An electrocardiogram shows sinus tachycardia with a single PVC. Chest x-ray shows minimal scarring in the right lower lobe. Laboratory studies show a hematocrit of 27%, hemoglobin of 9.1 g/dL, platelets of 298,000mm3 , MCV 78 mm3, sodium of 139 mEq/l, potassium of 4.1 mEq/l, blood urea nitrogen of 16 mg/dL, and creatinine 0.9 mg/dL. The most appropriate next step in the patient's management is a



A. cardiac stress test to rule out 3 vessel coronary artery disease
B. colonoscopy to rule out colon cancer
C. high resolution CT scan (HRCT) to rule out pulmonary fibrosis
D. iron pills and follow up in 3 months
E. ventilation-perfusion (V/Q) lung scan to rule out chronic pulmonary emboli

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B.

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b.

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B. colonoscopy, but I wanted to do FOBT before doing colonoscopy

The correct answer is B. It is important to remember that anemia can present with dyspnea on exertion and a complete blood count should always be part of this work up. This elderly patient has an iron deficiency anemia with hemoccult positive stool. A GI malignancy needs to be ruled out and colon cancer is the most likely etiology in this patient population. Therefore, a colonaoscopy is imperative.Although ischemic cardiomyopathy or silent ischemia can certainly present with progressive dyspnea on exertion, there are other things in the patient's history to suggest the cause of his symptoms. A cardiac workup (choice A) at this time is not the most pressing issue.HRCT (choice C) is a very good test to evaluate for pulmonary fibrosis. It is likely that the CXR would show more abnormalities. The minimal scarring mentioned at the right lower lobe is likely from his prior pneumonia mentioned in the past medical history, and is not causing the patient any symptoms.The patient is presenting with a microcytic anemia. The most likely cause is iron deficiency. However, it must always be remembered that the finding of a microcytic anemia should always prompt the immediate search for an underlying cause. So although the patient will likely require iron supplementation (choice D), follow up in 3 months with no other diagnostic test is not appropriate.A V/Q scan (choice E) can rule out chronic pulmonary emboli, which is certainly a cause of progressive DOE, but as mentioned previously, there are other things in the patient's history to suggest the cause of his symptoms.