Urinary calculi are hard crystals that form anywhere along the urine system—kidney, ureter, bladder, or urethra. When they shift, they send sharp, unmistakable signals. Sudden flank pain is the headline. It feels like a knife below the ribs and shoots into the groin as the stone moves. Nausea and vomiting ride along. The gut shares nerves with the urinary tract, so the pain triggers a sick stomach. Blood in the urine is common. The stream may look pink, brown, or tea-colored, and the change can appear even when pain is mild. Urinary urgency shows up next. You race to the... Learn more