Small, smooth kidney stones may remain in the kidney or pass without causing pain (called "silent" stones). Stones that lodge in the tube that carries urine from the kidneys to the bladder (ureter) cause the urinary system to spasm and produce pain. The pain is unrelated to the size of the stone and often radiates from the lower back to the side or groin.
A "small" stone (usually 4 mm in diameter or less) has a 90% chance of spontaneous passage. Stones that are 8 mm in diameter or larger usually require medical intervention.
Other symptoms of kidney stones may include the following:
- Blood in the urine (hematuria)
- Increased frequency of urination (urinary urgency)
- Nausea and vomiting
- Pain during urination (stinging, burning)
- Tenderness in the abdomen and kidney region
- Urinary tract infection (UTI; fever, chills, loss of appetite)
Kidney stone complications include kidney damage and scarring, decreased kidney function, obstruction of the ureter, recurrent stones and infections, and renal colic (severe pain that radiates from the kidney region to the abdomen and groin).