Kidney stones: can I protect myself?

Dr Schalk Wentzel, a urologist at Mediclinic Bloemfontein, explains how kidney stones form and how to avoid them.

Your kidneys work hard around the clock to filter waste from your blood, creating urine that contains calcium, phosphate, oxalate, and uric acid. Usually, these substances are very diluted, so they easily flow out when you urinate. But if your urine becomes concentrated, because you’re dehydrated, for instance, these minerals and salts can bind together to form a kidney stone. 

Dr Wentzel says a major risk factor for kidney stones is low urine volumes.

“This can be a result of dehydration, strenuous exercise, hot weather or not drinking enough fluids,” he explains. In addition, if you – or a family member – have had kidney stones before, eat a lot of protein, salt and sugar, are overweight, have had intestinal surgery in the past or suffer from kidney disease, you might be more likely to develop stones.

Symptoms

Kidney stones can range in size from a grain of sugar to a golf ball. Generally, you won’t experience any discomfort until the kidney stone passes from your kidney into the ureter – one of two small, delicate ducts that carry urine into your bladder.

“At this point, you might experience intense back pain below your ribs, painful urination, nausea and vomiting,” says Dr Wentzel. A CT scan or MRI will confirm whether your discomfort is due to kidney stones – and the treatment your doctor suggests will depend on the size of the stone. “If the pain isn’t too bad, you might be advised to wait and see if your system can flush out the kidney stone without surgical intervention.” Taking painkillers and drinking lots of water will help. You may also be given medication that relaxes the ureter to help you pass the stone.

If the stone is too large, however, a urologist can remove it or break it into small pieces using shockwave lithotripsy while you’re under anaesthetic.  Alternatively, your doctor might insert a cystoscope or ureteroscope through your urethra to see the rest of your urinary tract. Once the stone is found, they can remove it or break it into smaller pieces. This is usually a day procedure.

“The best way to prevent kidney stones is to drink at least eight glasses of water a day,” Dr Wentzel advises. “Limiting sodium and animal proteins – such as meat and eggs – can also help prevent kidney stones. If you have a health condition that makes you more predisposed to developing kidney stones, your healthcare professional might prescribe medication.”