Which of the following findings suggests a patient may have an upper urinary tract infection?

Flank pain on palpation is a key indicator of an upper urinary tract infection, which typically involves the kidneys and ureters. Infections such as pyelonephritis often present with tenderness in the flank area, where the kidneys are located. This pain is a result of inflammation and irritation in the upper urinary tract structures, signaling a possible kidney involvement.

The other findings may point to urinary tract issues but do not specifically indicate an upper urinary tract infection. For instance, palpation-induced pain over the pubis typically suggests a lower urinary tract problem, such as a bladder infection or irritation. Increased urgency and frequency of urination are common symptoms of a lower urinary tract infection as well. Nausea and vomiting can occur with various conditions, including gastrointestinal issues, but are not specific to upper urinary tract infections. Therefore, flank pain is the most direct and relevant symptom associated with upper urinary tract infections.