Kidney Stones and Endourology

What kidney stones are

Urine carries dissolved minerals and salts. When there is too little water to keep them dissolved, or too much of a particular mineral, they begin to crystallise and clump together. Given time, that becomes a stone.

Most stones are made of calcium oxalate. Others are made of uric acid, or form because of a long standing urinary infection. A small number are inherited. Stones can sit quietly in the kidney for years and cause nothing at all. Trouble usually starts when one moves into the ureter, the narrow tube between kidney and bladder, and blocks it.

Symptoms that suggest a stone

• Severe pain that starts in the loin or back and travels round towards the groin, often coming in waves
• Blood in the urine, either visible or found on a urine test
• Nausea and vomiting alongside the pain
• A persistent need to pass urine, or burning when you do
• Fever or shivering, which changes the situation entirely and needs same day assessment

How a stone is assessed

Assessment starts with the history and an examination, along with a urine test and blood tests to check kidney function and look for infection.

Imaging confirms it. An ultrasound is often the first scan and is useful for spotting a swollen kidney. A low dose CT scan of the kidneys, ureters and bladder gives the clearest picture, showing exactly where the stone sits, how big it is and how dense it is. Those three facts largely determine what treatment makes sense.

Treatment approaches

Waiting and watching

Stones under about five millimetres have a good chance of passing without any procedure. This is managed with fluids, pain relief and sometimes medication that relaxes the ureter, along with a plan for when to come back if it does not pass.

Shock wave treatment

Focused sound waves are directed at the stone from outside the body to break it into fragments small enough to pass. There is no cut and no telescope. It suits certain stone sizes and positions better than others.

Telescopic laser surgery

A very fine scope is passed along the natural urinary passage to reach the stone directly, and a laser breaks it up so the pieces can be removed or passed. This treats stones in the ureter and, with a flexible scope, stones inside the kidney itself. There is no external wound.

Keyhole kidney surgery

For large or branched stones filling the kidney, a small track is made through the back directly into the kidney so the stone can be broken and removed in one sitting. This is the approach that clears high stone volumes efficiently.

Urgent drainage

When a blocked kidney is infected, the priority is to drain it immediately with a stent or a tube through the skin. The stone itself is dealt with once the infection has settled.

Recovery and the stent question

Most stone procedures are day case or single night stays. Normal activity usually resumes within a few days, and desk based work sooner than that.

A temporary stent is often left inside the ureter afterwards to keep it open while any swelling settles. It is a soft tube, it is not visible from outside, and it is removed after a short interval. Many people notice more frequent urination, some urgency and a little blood while it is in place. That is expected and it settles once the stent comes out.

Stopping stones coming back

Stone disease has a real tendency to recur. Roughly half of people who form one stone will form another within several years, which makes prevention worth taking seriously.

Fluid intake matters more than any other single factor. Enough water to keep urine pale, spread across the day, does most of the work. Cutting back on salt helps. Beyond that, anyone who forms stones repeatedly, forms them young, or has a single working kidney should have the stone analysed and a metabolic assessment done, so that prevention can be aimed at the actual cause rather than guessed at.