The patient is a 44 year old male who presented with a chief complaint of: “my ribs hurt when I cough”. He has had a persistent non-productive cough associated with severe rib and back pain for 4 months along with increased fatigue and weakness, but no fever or chills. His labs from an outside physician's office were remarkable for hypercalcemia and increased creatinine.

2. What causes increased creatnine?