Kidney stones are very common in Trinidad and Tobago and advice is not in short supply. Indeed there are many myths that go along with this advice. Folks often ask about diet and kidney stones as well as treatment options. I have tried to summarize the important points in this article. While an individual may have specific requirements based on an assessment by his/her urologist, this article deals with general advice for the average stone former.
Diet and kidney stones
Perhaps the best dietary modification you can make is to increase liquids in your diet as lots of liquids prevent the urine from becoming too concentrated. A good rule is to drink enough to make 2-3L of urine a day and for this we recommend water as your primary fluid source. It is always helpful to carry around a water bottle for ease of access! You may consider adding some lemons to the water for flavor and this has the added benefit of alkalinizing the urine which in itself may help to prevent stones.
Other dietary rules to follow include:
Restriction of animal protein as these increase your risk of stones – this includes fish. Animal proteins should be used in moderation and some should take the form of dairy to ensure that you are getting enough calcium. Generally, you should limit foods with a high potential renal acid load (PRAL). Foods with a high PRAL include eggs, meat and cheddar cheese. A list of high PRAL foods can easily be found on the internet. There is no evidence that drinking “hard water” leads to an increase in kidney stones and hence bottled water is not necessary.
In the kidneys calcium is excreted along with sodium; as more sodium is eaten and excreted, there is a corresponding increase in calcium pushed into the urine and this could lead to kidney stones. You should therefore limit your salt intake as best as you can. Try not to add extra salt and perhaps look to spices to enhance flavor.
Many persons have completely eliminated dairy from their diets and this is ill advised. It has been found that removing calcium completely will in fact lead to an increase in stone formation. We therefore recommend eating normal amounts of calcium (1200mg/day) from both non-dairy and dairy sources. Calcium supplements are a different matter and may increase your risk of stones and if you are a stone former, should be avoided if possible. You should discuss your specific needs/risk with your urologist.
You should use plenty of fresh fruits and vegetables which are high in citrate and have a low PRAL. Citrate is a potent inhibitor of stone formation. It should also be noted that cucumber and tomato seeds do not lead to an increased risk of stones.
Calcium oxalate is the most common stone constituent and you should make an effort to limit (not necessarily eliminate) foods with a high oxalate content which include chocolate, tea, soy, strawberries, and spinach. This is especially important if you are known to form calcium oxalate stones.
Treatment options for kidney stones
Fortunately, we have many treatment options for stones in Trinidad and Tobago and choice of treatment will depend on several factors including stone size, hardness and location as well as problems the stone may be causing such as infection or blockage. A CT scan with or without an X-ray will help provide valuable information as will blood and urine test. Some stones may be small and may not require any treatment at all.
The ureter is the tube which leads from your kidney to your bladder and a stone lodged in this tube is extremely painful! It can also become infected and may even cause kidney damage. If the pain settles, your urologist may give the stone a chance to pass. This is an option if the stone is small, usually less than 1cm, and there are no signs of infection or kidney damage. You may be prescribed painkillers as well as a tablet which relaxes the ureter and helps the stone to pass. If your stone is causing an infection your urologist will recommend placement of a stent which is a thin plastic tube that is placed through your urine tube and which runs from the kidney to the bladder – this helps drain the kidney and the infection. This procedure does not require a cut. Definitive treatment will take place once you have recovered from your infection as the stent alone is not a treatment for stones and should not remain in place any longer than is necessary for you to have definitive treatment.
There are several surgical options for kidney and ureteric stones:
1.Ureteroscopy – This involves passing a very long, thin camera up the ureter and may also be used for stones in the kidney. This allows us to break the stone with a laser. Following this, the urologist may leave a stent in place for a few days. Ureteroscopy is quite a safe procedure and may even be done as a day case.
2.Extracorporeal shockwave lithotripsy (ESWL) – This machine generates shockwaves to break up kidney stones without making a cut. Once the stone shatters, the small fragments are passed out in the urine. This is a same day procedure but you may require some sedation. Not everyone is suitable for ESWL as hard stones make shattering the stone difficult and there are limits on the size of stones which can be shattered. Some patients may need multiple sessions for full clearance.
3. PCNL - Previously, we made fairly large cuts to remove kidney stones and some surgeons still offer this. A much more modern and less invasive option is called percutaneous nephrolithotomy or PCNL. This is a good option for larger stones in the kidney and fortunately is offered locally. A needle is used to puncture the kidney through the side or the back and a wire is passed into the kidney. A tiny tract, usually less than ? of an inch wide is developed and a camera is placed into the kidney – the stone can then be broken up with a stone breaker or laser. In this way there is only a tiny cut on the skin and recovery is much faster.
You should discuss your particular case in great detail with your urologist before deciding which option is right for you
Satyendra Persaud MBBS DM (Urol) FCCS FRCS
Consultant Urologist, San Fernando General Hospital
Lecturer in Urology, University of the West Indies