Review Question - QID 212735

A 44-year-old woman presents to the emergency department with confusion starting this morning. Her husband states that she initially complained of abdominal pain, diarrhea, and fatigue after eating and has been with her the entire time. She has vomited 3 times and progressively became more confused. Her past medical history is notable for morbid obesity, diabetes, hypertension, dyslipidemia, a sleeve gastrectomy 1 month ago, and depression with multiple suicide attempts. Her temperature is 98.0°F (36.7°C), blood pressure is 104/54 mmHg, pulse is 120/min, respirations are 15/min, and oxygen saturation is 98% on room air. Her physical exam is notable for generalized confusion. Laboratory values are ordered as seen below.

Serum:
Na+: 139 mEq/L
Cl-: 100 mEq/L
K+: 3.9 mEq/L
HCO3-: 24 mEq/L
BUN: 22 mg/dL
Glucose: 41 mg/dL
Creatinine: 1.1 mg/dL
Ca2+: 10.2 mg/dL
C-peptide level: normal

Which of the following is the most likely diagnosis?