Kidney stones - prevention and treatment
Matthew Bultitude is a consultant urological surgeon practising at Guy's and St. Thomas' Hospital in London. He has a subspecialist interest in stone disease, and in this article he answers questions about the common problem of kidney stones.
Matt, how did you become interested in urological stone disease?
I was fortunate to work as a junior doctor in the stone unit at Guy's and St. Thomas' Hospital and following on from that I was offered a research position which I gladly took up. I undertook a number of clinical projects during that period including an MSc thesis assessing the safety of flexible ureteroscopy. I really enjoyed the challenges that stone disease creates and this has carried on throughout my career.
Do you see an increasing rate of stone disease in the UK, and what is the cause of this?
There is no doubt that there has been a steady increase in the number of stone cases in the western world and the UK is no exception. The lifetime risk may now be as high as 12% (American data) and although more common in men, they are becoming increasingly prevalent in women. This is essentially due to a combination of increasing obesity with poor diets (high in animal protein, fizzy drinks, processed foods, salt etc) and low fluid intake.
What have been the major developments in surgery for stone disease in the last few years?
I remember (as a boy with a urological father) when the first public lithotripter arrived in the UK (St. Thomas' Hospital) in the 1980's. This revolutionised stone treatment and continues to be a common treatment. What has changed over the last decade has been the development of smaller (diameter) and more robust instruments allowing us to pass telescopes up the urinary tract to the kidney to treat stones (flexible ureteroscopy). For large stones percutaneous surgery (PCNL) remains the standard and recent developments have seen some interesting changes to how this is done with smaller and smaller instruments and also in new surgical positions with many surgeons now choosing the supine position (so lying on side) rather than prone (lying on front).
Does shock wave therapy have an ongoing role in stone management?
There is no doubt that shock wave lithotripsy has been on the decline but in my opinion it is still a useful treatment for many patients. Choosing the correct stone for this treatment is important and as it works better in a thin patient with a smaller stone, rather than trying it in everyone. However I increasingly find patients prefer the more definitive choice of surgery with ureteroscopy to fragment the stone with a laser as although it is more invasive, the outcomes are more predictable.
Calcium oxalate stones are the most common kind of kidney stones. What is your advice to someone who has had a stone like this, to prevent future stone formation?
I often give quite detailed advice about stone prevention, although the summary of this is a normal healthy diet with lots of fluid (which is what we should all be doing!). In principal we should aim for a diet with:
- Enough fluid to produce at least 2 litres of urine per day. The actual amount will be different for everyone but usually a minimum of 2.5 litres in per day is required. This is the most important advice.
- Limited animal protein (meat and fish)
- Low salt
- Plenty of fruit and vegetables
- High fibre
- A normal calcium intake - so cutting back is often the wrong thing to do.
For calcium oxalate stone formers there are some foods high in oxalate and limiting intake of these may also help.
What developments do you see on the horizon for kidney stone treatment?
I think surgery will continue to improve with better quality and smaller instruments becoming available. Shockwave lithotripsy will probably continue to decline (as discussed above). What would be a game changer is the development of effective medication that could reduce the chance of stones growing in urine although I suspect we are many years away from this!
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