A 58 year old woman with a long history of alcoholism presents with diarrhea, general weakness, and a 9lb weight loss in the past 3 months. Further history reveals that she has been having difficulties driving at night as well as episodic upper abdominal pain not relieved with antacids or proton pump inhibitors. Laboratory studies reveal a serum ionized calcium of 3.5mg/dL (N=4.5-5.6mg/dL); PT of 30 seconds (N=11-15seconds); PTT of 60 seconds (N=25-40seconds). What is the most likely etiology of this patient’s diarrhea?
a. Carcinoid tumor
b. Pancreatic cancer of the head of the pancreas
c. Chronic pancreatitis
d. Chronic gastritis
e. Celiac sprue