Final answer:
The most important finding for the nurse to report to the healthcare provider in a patient with urolithiasis is obstruction of the ureter.
Step-by-step explanation:
The most important finding for the nurse to report to the healthcare provider in a patient with urolithiasis is obstruction of the ureter. Obstruction occurs when kidney stones grow to a size that blocks the passage of urine through the ureter. This can cause severe pain in the flank, lower abdomen, and groin, as well as other symptoms such as nausea, vomiting, and hematuria.