Kidney stone: will it pass on its own, or does it need to be removed?

Why size and position matter

A stone hurts when it moves from the kidney into the ureter, the thin tube that carries urine to the bladder. The pain comes in waves from the side or back into the groin, and men often feel it in the testicle. Many people vomit with it.

Whether it passes depends mostly on its size and where it is. A small stone near the bladder end has a good chance of coming out. A larger stone, or one stuck high up, is less likely to. A CT scan, ideally a low-dose non-contrast CT, shows both, and is the test most urologists prefer.

Waiting it out safely

If the stone is small, the kidney is draining and the pain is controlled, your doctor may suggest watching for a few weeks. This means:

• Regular pain relief as prescribed; anti-inflammatory painkillers often work well if your kidneys are healthy
• Enough water to keep urine pale, without forcing litres down in one go
• A tablet that relaxes the ureter, if your doctor prescribes one
• Straining your urine through a sieve or cloth to catch the stone so it can be tested
• A follow-up scan to confirm the stone has gone, even if the pain stops

When removal is the better choice

Your urologist will usually recommend treatment if:

• The stone is large, or has not moved after a few weeks
• Pain keeps returning or needs injections to control
• The kidney is blocked and swelling on scan
• You have only one working kidney, or reduced kidney function
• There are signs of infection
• Your work or travel makes waiting risky, for example long-distance driving or flying

The options for removing a stone

Ureteroscopy is the most common. Under anaesthetic, a thin telescope goes up through the urine tube and bladder into the ureter, with no cut on the skin. The stone is broken with a laser and the pieces removed. Often a temporary soft tube called a stent is left inside for a short time to help drainage, and is removed later.

Shockwave lithotripsy breaks some kidney stones from outside the body, and very large kidney stones may need keyhole surgery through the back. Your urologist will explain which suits your stone.

Go to an emergency department now if

Stone pain with fever, shivering or feeling very unwell; pain you cannot control at home; vomiting so much you cannot keep water down; passing very little or no urine; or a stone when you have only one kidney. An infected blocked kidney needs urgent drainage, not waiting.

Common questions