Case Presentation: A 72-year-old male presented to the emergency room for macrocytic anemia and a creatinine of 9.72 mg/dL on outpatient lab work. Past medical history was notable for paroxysmal supraventricular tachycardia, gastroesophageal reflux disease and heart failure with reduced ejection fraction. On admission, he complained of six months of fatigue with constipation, 60 lbs [...]