An 86-year-old man comes to the physician for a 3-week history of generalized pruritis and loss of appetite. He has had an 8-lb weight loss during this time. He has had no nausea or vomiting. He has hypertension managed with amlodipine. BMI is 17. HR is 80. BP is 150/90. Examination shows excoriations on all extremities. Mental status is intact. Laboratory studies show:
Hemoglobin 11 g/dL
WBC 5,000/μL
Na+ 140 mEq/L
K+ 6.0 mEq/L
BUN 50 mg/dL
Cr 3.4 mg/dL
Which of the following is the most likely explanation for this patient’s anorexia?
