Critical anemia · light-headedness · bilateral leg swelling · Dx?

: 40-year-old man was referred to the emergency department (ED) with critical anemia after routine blood work at an outside clinic showed a hemoglobin level of 3.5 g/dL. On presentation, he reported symptoms of fatigue, shortness of breath, bilateral leg swelling, dizziness (characterized as light-headedness), and frequent heartburn. He said that the symptoms began 5 weeks earlier, after he was exposed to a relative with hand, foot, and mouth disease.