Bladder stones

A bladder stone is a hard lump made of urinary salts that has grown inside the bladder itself, rather than travelling down from the kidney. The reason is nearly always the same: the bladder has stopped emptying completely. Leftover urine stagnates, salts settle out, crystals stick to one another, and within a few months a stone forms that may be anything from a grain of sand to the size of a walnut. That is why a bladder stone is rarely a disease in its own right. More often it is the visible trace of another, hidden problem, and treatment that stops at removing the stone does not hold for long.

Why the bladder fails to empty fully

A healthy bladder is left almost empty after passing urine. If even a small volume stays behind every time, the conditions for a stone are already in place. Several things can get in the way.

• An enlarged prostate — the commonest reason in men over fifty, as the overgrown tissue squeezes the urethra.
• Narrowing of the urethra after injury, inflammation, catheterisation or surgery.
• Disturbed nerve control of the bladder: spinal cord injury, multiple sclerosis, long-standing diabetes with nerve damage, spina bifida. The bladder either fails to contract or works out of step with the sphincter.
• A long-term catheter or self-catheterisation. A catheter almost never leaves the bladder completely dry, and it also provides a surface on which salts settle.
• Prolapse of the bladder wall into the vagina in women, after childbirth, heavy work or years of straining with constipation.
• Pouches in the bladder wall (diverticula). Urine sits inside the pouch and is never flushed out.
• A bladder enlarged with a segment of bowel after reconstructive surgery: the bowel lining produces mucus, and salts build up around it.

Foreign bodies deserve a mention of their own: a stitch that has not dissolved, a broken piece of catheter, a forgotten coil. Each becomes a core around which a stone grows faster than usual. In children in hot countries, stones are linked not to obstruction but to dehydration and a monotonous diet. Finally, a small kidney stone may drop into the bladder and, if the outflow is restricted, stay there and grow a shell of its own.

What it feels like

• dull or sharp pain above the pubic bone, often worst at the end of passing urine; in men it spreads to the penis;
• the stream suddenly stops and restarts when you shift position, as the stone rolls towards the outlet and back;
• frequent urges, especially at night, and a feeling that the bladder is not empty;
• stinging and burning when passing urine;
• cloudy urine with sediment and a strong smell;
• blood in the urine, from a pink tinge to obvious red;
• in children, the return of night-time wetting; in boys, occasionally a prolonged painful erection.

A small stone may give no sign of itself for years and turn up by chance on a scan done for another reason. The absence of pain does not make it harmless: it keeps irritating the bladder wall and keeps infection going.

When help is needed straight away

• you cannot pass urine at all and the lower abdomen is becoming tight and painful — this is acute retention, and the bladder must be drained within hours;
• fever with shivering, loin pain, weakness or confusion appears — infection has travelled up to the kidneys and may enter the bloodstream;
• the urine turns bright red, with clots;
• lower abdominal pain will not settle and keeps you doubled over.

Blood in the urine deserves a separate word. Even when a stone has already been found and the explanation looks obvious, visible blood calls for a full look at the bladder. A stone and a bladder tumour not uncommonly exist side by side, and anything written off as "just the stone" turns easily into lost time.

Why a stone that "causes no trouble" still matters

Waiting for a stone to pass on its own is usually pointless and sometimes risky. Urine standing around it is a comfortable home for bacteria: hence the repeated bladder infections that respond poorly to short courses of antibiotics, and infections that climb to the kidneys. If the stone blocks the outlet, pressure is passed upwards, the drainage system of the kidney widens, and over time kidney function suffers.

There is also a rarer but more serious line. Years of mechanical irritation of the lining — by a large stone nobody removed, or by a catheter left in place for years — raises the risk of bladder cancer, including the squamous cell type. The same mechanism operates in chronic parasitic disease of the bladder (schistosomiasis) in people who have lived or spent long periods in Africa and the Middle East. The risk is small, but it is a solid reason not to leave a stone sitting for decades and not to skip planned catheter changes.

How the stone is found

Tests answer two questions at once: is there a stone, and what is stopping the bladder from emptying.

• Urine testing and culture show inflammation, blood, crystals and which bacteria are living in the bladder.
• Ultrasound with a full bladder is usually the first step: it shows the stone and the thickness of the wall, and afterwards measures how much urine is left behind.
• A plain X-ray is not always enough: uric acid stones are transparent to X-rays and are common in the bladder. A clear film does not rule a stone out.
• A CT scan without contrast is the most reliable option and picks up stones of any composition.
• Cystoscopy — looking inside the bladder with a thin instrument carrying a camera. It shows the stone, the state of the lining, any pouches and any suspicious areas, and the stone is often removed during the same procedure.

It is worth sending the stone for analysis once it is out. What it is built from — uric acid, calcium oxalate or the salts that form during infection — decides what happens next.

How the stone is removed

A bladder stone rarely leaves on its own: it grows in a dead end and by then is usually wider than the urethra. Drinking heavily helps only with the smallest grains, and only if the outflow is clear.

The standard approach is cystolitholapaxy through the urethra: an instrument with a camera is passed into the bladder, the stone is broken up with a laser, ultrasound or mechanically, and the fragments are washed out. It is done under general or spinal anaesthesia, an antibiotic is given as a precaution, and a catheter is sometimes left in for a day or two. Large stones, and stones in children, are more often taken out through a small puncture above the pubic bone so as not to injure a narrow urethra. Open surgery is needed rarely: for very large or multiple stones, or when the prostate is to be operated on at the same time.

The most important part is dealing with the cause. Men with an enlarged prostate are offered medication (alpha blockers, 5-alpha reductase inhibitors) or prostate surgery. Where nerve control is impaired, the catheterisation schedule and the type of catheter are reviewed. A prolapsed bladder wall may be helped by a pessary or by repair surgery. A diverticulum is removed if necessary. Without this step, stones come back within a few years.

What lowers the chance of a repeat

• drink enough: for an adult with no fluid restriction, around two to three litres a day, so that the urine stays pale;
• empty the bladder regularly rather than holding on for long stretches;
• learn double voiding: wait ten to twenty seconds after the stream ends and try again;
• do not let constipation take hold, since a loaded bowel physically hinders bladder emptying;
• with a long-term catheter, keep to the replacement schedule and to careful hygiene;
• after the stone is removed, attend the follow-up scan with a residual urine measurement even if nothing is troubling you.

Online consultation

In an online consultation the doctor goes through exactly how your urination has changed, whether there are signs of infection or retention, explains which tests make sense first and why an X-ray alone is not enough, helps you read reports you already have, and advises which specialist to see in person and how quickly.

This material is for information only and does not replace medical advice.