Q. A 50-year-old male presents to the emergency department with complaints of excessive thirst, frequent urination, and abdominal pain. He states that he has not been feeling well for the past two weeks, and also describes symptoms of excessive fatigue, muscle weakness, and constipation. The patient saw his primary care provider last week with similar complaints, and a 24-hour urine test was ordered, along with bloodwork, and a urinalysis, which demonstrated a urine calcium-to-creatinine ratio of 0.03. Subsequently, a renal ultrasound showed multiple, bilateral renal stones, and was otherwise normal. Incidentally, the patient also reports pain in his left index finger, and denies any history of trauma. On physical examination, his temperature is 37 degrees Celsius (98.6 Fahrenheit), heart rate 70/min, respiratory rate 18/min, blood pressure 95/50 mm Hg. Mucous membranes are dry, and the patient appears moderately dehydrated. His neck is supple, with no masses or thyromegaly detected, and cardiopulmonary examination is unremarkable. The patient’s abdominal exam reveals no masses, though mild rebound tenderness is noted, along with right-sided costovertebral angle tenderness. Evaluation of his left hand demonstrates marked pain to palpation just proximal to the first metacarpophalangeal joint. You order a urinalysis, which shows clear, pale urine with a decreased pH, low specific gravity, and is positive for protein and blood. A chemistry panel reveals a serum calcium level of 15 mg/dL, blood urea nitrogen 25 mg/dL, and creatinine of 2.0 mg/dL. You also order an x-ray of the patient’s hands (see image). Based on the information you have at this point, what is the most likely diagnosis?