Which is a hallmark symptom of kidney stones?

• A. Sudden, severe flank or groin pain
• B. Nausea and vomiting
• C. Hematuria
• D. Urinary urgency or frequency

Answer: (A)

The main signal here is the abrupt, intense pain caused by a stone obstructing the urinary tract. When a stone moves or lodges in the ureter, the smooth muscle contracts forcefully and the ureter spasms, producing sudden, severe flank pain that often radiates toward the groin. This pain tends to come on quickly and can feel like waves as the ureter contracts to move the stone along. The location and the intensity of this pain are what make it a defining feature of kidney stones.

Nausea, vomiting, and sweating can accompany the pain because of the body's reaction to severe pain, and blood in the urine is common due to irritation of the urinary tract lining. However, those symptoms can occur with many other conditions. Urinary urgency or frequency points to irritation of the bladder or lower tract and isn’t as specific to stones. So the standout, hallmark symptom is the sudden, severe flank or groin pain.