Workup for Colicky Abdominal Pain for USMLE

In Episode 5 of Med School Question of the Week for USMLE, Sam Taylor examines the following:

A 35-year-old woman presents to the ER with excruciating back pain. She was taking a nap after work and was awoke to intense burning colicky pain on the left side of her back. She has a history of Crohn’s disease and was recently treated with corticosteroids for a flareup. For the past several weeks, however, her diarrhea and abdominal pain had been improving. She has no other medical conditions. Her vitals are significant for HR 102 and blood pressure of 140/96. She is afebrile. Urinalysis indicates microscopic humaturia, What most likely contributed to her current condition?

• Ingestion of a toxic substance
• Increased production of uric acid
• Bacterisl infection in the renal pelvis
• Impaired absorption of bile salts
• Impaired absorption of divalent cation