Kidney stones: an expert's overview: part 2

In the second article of a two-part series, leading consultant urological surgeon Mr Jyoti Basu explores the treatment options available for kidney stones and reveals what lifestyle modifications can be implemented to prevent such stones from occurring.

What treatment options are available for kidney stones and how do they arrive based on the size, location, and composition of the stones?

Based on the CT scan, we have an idea of how to treat the kidney stones. This is called a Hounsfield unit. On the CT scan, we can measure how dense the stone is, which gives an idea of whether the stone is of calcium oxalate or calcium phosphate, having a density similar to that of bone. On the other hand, softer stones such as uric acid stones or infectious stones appear less dense on a CT scan, with less of a Hounsfield unit posing a lower risk.

On the other hand, if you find that the patient is suffering from recurrent urinary tract infections (UTIs) and has a kidney stone, you can normally determine that the stone is causing the infection or sometimes the infection can lead to stone formation.

There are certain bugs in the urine, the primary being proteus, a bug, which can lead to stone formation. If you have a urinary tract infection and your doctor has found this bug through a urine examination, they will then ask for a specific test or a CT scan to look for a stone, because a proteus infection in the urine is often associated with a kidney stone formation. The stones in this case are infective stones formed of calcium, aluminium, magnesium, also called a triple phosphate stone.

These stones are a lot thinner. On CT scan and can appear to be a bit lighter. Based on the CT scan findings, we can think about the different treatment options, but we must ask where the stones are, if they are in the kidney or in the ureter. If the stones are in the kidney and if they are less than one centimetre in size, or 1.2 centimetre at most, shock wave lithotripsy is the best treatment option. It focuses sound waves to the kidney from outside, the stone breaks and the patient passes the stone by taking painkillers.

If the stone size increases, lithotripsy can be used as a treatment option.  It can be done up to 15 millimetres, although there is a risk that the stone will break and they will form larger fragments, which will drop down and line up the ureter in the process of passing, and possibly get blocked.

When lithotripsy is performed on a large stone, fragments can drop down and cause blockage, therefore we try not to go below 12 millimetres at the most.

If the stone is in the lower part of the kidney, lithotripsy will not be very effective because the stone will break, but the stone fragments will have to climb out and then come out. Stones often break and stay there. Eventually, when scanned again after six or nine months, they often haven't moved and are clumped back together and the procedure is pointless.

Another treatment option is flexible ureteroscopy and laser. During this, we pass a bendy telescope from the bladder into the kidney and pass a laser fibre, break the stones into small fragments, get a basket and lift them out and take it out, or we can lead the very, very fine dust sand like particles completely, and the patients can pass there.

If the stone is larger than two centimetres, we have to do is we perform percutaneous nephrolithotomy. This means that you treat the stone by puncturing the kidney, getting a telescope inside the stone and then directly hitting the stone with various forms of energy, fragmenting them and washing them out or taking them out.

Once a stone is formed, there is a 40% chance that another stone will form within the next three to four years. If the stone forms again, it will need to be cut. Minimally invasive techniques are useful for this.

It is not uncommon to have to redo the procedure after a long amount of time and I think these minimally invasive techniques for dealing with stone surgery have revolutionised the whole stone disease and the way stone disease is managed.

The way to drill deal with uric stones is slightly different because now the stones have come down into the uta, and normally if they are six millimetres or below six millimetres, there is more than 70% chance of passing them by themselves. If they do, we follow them up with repeat CT scan.

If they do not pass their stone within around two months, we have to intervene, and the best way of doing it is by going up with a telescope, getting to the stone, lasering them, breaking them up and leaving them with a plastic tube called a stent, which helps to drain the kidney in the interim period. Once the stent comes out, all the stone fragments will go.

Are there any lifestyle modifications or preventive measures that can help reduce the risk of kidney stone formation?

It is important to uncover the cause. For the majority of the kidney stone formers, we cannot find a cause unless the kidney stone is made up of uric acid, a light-coloured stone which can be seen on the CT scan. There are various special CT scans available, called dual-energy CT. If the specialist determines that it is a uric acid stone, it forms in acidic urine.

It is possible to alkanalise the urine by taking simple things such as potassium citrate or household items like bicarb or soda baking powder that can dissolve the part of the stone or entire stones, if it is an acid. If you make your urine alkaline, the stone dissolves.
 

There are various ways to modify your lifestyle in order to prevent uric acid stones. These include modifying your diet to reduce or exclude uric acid and avoid including lots of animal protein, such as red meat, fish and eggs.

Additionally, it is advisable to take medications such as allopurinol, which reduces the binds of uric acid and reduces the excretion of uric acid in the urine. For stones such as calcium stones, you must undergo blood tests to determine the level of calcium levels in the urine.

For other stones, such as calcium stones, you have to do blood tests to discover the calcium levels in the urine, and you do a 24-hour urine estimation to see what is in the urine, which is causing the stone. These tests are only for people who are frequently form stones.

However, if you don’t frequently form stones, you can implement things such as lifestyle modifications. It is recommended to increase fluid intake; to take around two/ two and a half litres. However, there is no specific amount; you have to drink so that your urine is pale, therefore, before flushing the toilet, you must look at the colour of the urine. In fact, there is a urine chart which you can download on your phone, to analyse the colour of your urine. If your colour doesn't match that on the phone, you must drink more water.

Regarding animal protein, it should not take up more than a quarter of the plate. The rest should be filled with vegetables, carbohydrates and salads. Finally, it is important to eliminate free salt from the diet. Free salt or sodium has been seen to accelerate stone formation, if you have a propensity to it.

However, if somebody is a recurrent stone former, there is a pathway. We investigate these patients by blood test by 24-hour urine estimation, and then offer them medications or other specific dietary interventions to eradicate stone formation.

If you are suffering from kidney stones and would like to book a consultation with Mr Basu, simply visit his Top Doctors profile today