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 bathroom every few minutes, pass only drops, and feel burning like hot sauce.

Some people see tiny gravel or grain-like bits in the urine once the stone starts to break apart.

If the stone blocks the pipe completely, the bladder over-fills and you can’t go at all—an emergency.