Nationally acclaimed Urology Clinics Manchester answers some common questions about kidney stones.
How common are kidney stones?
It is estimated that around one in 10 adults in the UK will suffer from kidney stones at some point in their life. Men are affected more than women. They are quite rare in children. The incidence has been increasing recently, probably due to changes in our diets.
What are kidney stones made of?
The majority (80%) of kidney stones are calcium based (calcium oxalate being the most common). The other types include uric acid, infection stones and cystine as well as some other rarer stone types.
Why do people get kidney stones?
The most common reason is poor hydration, which results in concentrated urine. A diet that is high in salt and meat and having a family history of kidney stones can also increase the risk. Certain metabolic abnormalities can cause an imbalance in the constituents of the urine, which, in some cases, favours kidney stone formation. Urinary tract infections with the bacteria proteus are also associated with kidney stones and certain medications can increase their likelihood too.
What are the symptoms?
The most common symptom is pain, which can be very severe if the stone is stuck in the tube that drains the kidney (the ureter). It is generally felt in the back (loins) and can move to the front of the abdomen, groins and testicle (in men). There may be accompanying urinary symptoms, such as pain on urination, frequency, urgency, and the passage of blood in the urine. Sometimes, there may be a temperature if there is also an infection present.
How is a kidney stone diagnosed?
Kidney stones can show up on an X-ray and ultrasound, but the most accurate test is a CT scan.
What are the treatment options for kidney stones?
Not all kidney stones need treatment. Small stones in the kidney, which are not causing any symptoms, may be left alone and monitored. Small stones in the tube draining the kidney (ureter) may also pass by themselves, sometimes with the aid of medication. However, this process should be monitored by a specialist.
There is a choice of treatments for stones that need treating. The most common being outpatient-based shockwave therapy (extracorporeal shockwave lithotripsy aka ESWL), day-case telescopic surgery through the water pipes (ureteroscopy and laser stone f ragmentation) and keyhole surgery (percutaneous nephrolithotomy aka PCNL). The choice is guided by the size and position of the stone, amongst other factors. It is rare that open surgery is needed, so recovery f rom the common kidney stone treatments is generally quick.
I have had a kidney stone in the past, how do I prevent another one forming?
If you have had a stone in the past, you are more likely than the average person to form another stone in the future. The most important thing you can do is to keep well hydrated and make sure your urine is not concentrated. Often, patients are advised to drink two litres or more of water per day, but the amount one should drink will also depend on factors such as how active you are and how hot the weather is. A good rule of thumb is to drink enough to ensure that your urine is always pale in colour.
Other dietary measures that have been linked to reducing the risk of kidney stones include reducing or moderating salt and meat intake. It is important to recognise that a lot of processed foods, takeaways and ready meals are high in salt content. There is also some evidence that the consumption of f resh lemon juice reduces the risk of kidney stones. In summary – keep well hydrated and have a balanced and healthy diet with less salt and meat.
Some less common types of kidney stones and certain metabolic abnormalities may need more specific advice and medications, which should be directed by a specialist.
