Kidney Stone

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Within Asia, the prevalence of urinary stones is estimated at between 5-19%, with a geographic distribution of a “stone-forming belt “in Southeast Asia. The recurrence rate of stone disease ranges from 21- 53% after 3-5 years. Worldwide, the prevalence of kidney stones is higher in males than in females. This is likely due to differences in diet and activity levels. However, in recent years, the differences in urinary stone disease between males and females have largely narrowed. This is possibly due to changes in activity level and diet.

In recent years, we have also begun to notice younger patients getting diagnosed with kidney stones. This may be related to a change in diet that is high in animal protein and salt, fueled by inadequate fluid intake.

Causes

Kidney stones are usually formed when the urine becomes concentrated, causing mineral deposits to group together and become crystals that form stones. These start small and then enlarge over time as more crystals form. The risk factors for kidney stones include:

• Family history.
  
• Personal history of stones.
  
• Insufficient fluid intake - a lack of water intake that is appropriate for activity level usually causes urine to become concentrated, increasing the risk of urinary stone formation.
  
• Poor dietary habits - diets high in salt and protein increase the risk of urinary stone formation. This is especially true for diets that contain a lot of sodium as it increases the amount of calcium in the urine and therefore, the risk of stone formation.
  
• Poor dietary habits - diets high in salt and protein increase the risk of urinary stone formation. This is especially true for diets that contain a lot of sodium as it increases the amount of calcium in the urine and therefore, the risk of stone formation.
  
• Obesity.
  
• Intestinal disorders or surgery - gastric bypass surgery and inflammatory bowel disease can affect calcium and water absorption, increasing the risk of urinary stone formation.
  
• Certain medications and supplements, especially when taken excessively, including Vitamin C.
  

Symptoms

You may not have symptoms if you only have a small kidney stone. This may be found incidentally during health screening when there are blood traces found in the urine or on a screening X-ray.

Larger stones or stones that have travelled down into the ureter may cause symptoms such as back or lower abdominal and groin pain, fever, blood in the urine, or pain when passing urine as well as fever due to obstruction and infection. These should be evaluated by a doctor to assess if kidney stones are the cause.

Diagnosis

Your doctor may order imaging, including X-rays or a CT scan to diagnose kidney stones. These would help to determine the size and location of the kidney stones, and whether the stones are causing any obstruction. Urine and blood tests may also be ordered to assess if there is concurrent urinary tract infection and whether kidney function is affected by the kidney stones.

Treatment

Kidney stones should be treated if they are causing symptoms such as pain or infection. If left untreated, they could become larger, increase in number, or even drop into the ureter, causing obstruction and kidney swelling. In the long term, this can lead to kidney failure if left untreated, or cause recurrent urinary tract infections and symptoms such as blood in the urine or pain.

For some patients who only have one working kidney, stones within this single good kidney should be treated as far as possible to prevent any complications.

In some cases, the body can pass out urinary stones on its own (without medication or surgery). This is usually when the stones are small and there is no obstruction in the urinary system.

For medications to help stones pass, this is usually only applicable for stones within the ureter. We would prescribe certain medicines to help relax the muscles of the ureter to help the stones pass. These medications are usually given for up to a month to help the stones pass.

For stones within the kidney, medications to help them pass usually do not work. However, for specific stone types, such as smaller uric acid stones within the kidney, it is possible to take medications to dissolve them, but this can take some time to work - ranging from weeks to months.

There are a few types of surgical treatments that can be performed for urinary stones. The least invasive method is Extracorporeal Shockwave Lithotripsy (ESWL). This is an outpatient procedure done in the clinic that attempts to fragment and break stones using focused sound waves.

Within Asia, the prevalence of urinary stones is estimated at between 5-19%, with a geographic distribution of a “stone-forming belt “ in Southeast Asia.

Surgery

There are a few types of surgical treatments that can be performed for urinary stones. The least invasive method is Extracorporeal Shockwave Lithotripsy (ESWL). This is an outpatient procedure done in the clinic that attempts to fragment and break stones using focused sound waves. When the stones are broken into smaller pieces, they will pass more easily on their own. This is suitable for smaller stones in certain locations within the kidney.

For relatively small stones (usually under 2cm), minimally invasive surgery can be performed under general anaesthesia as a day procedure through Retrograde Intrarenal Surgery (RIRS). This uses a small endoscope to go through the natural urinary passage into the ureter or kidney, and uses a laser to break the stones into smaller pieces. The stones can then be removed during the procedure. There is no skin incision.

For larger stones over 1.5-2cm in size or smaller stones in the lower part of the kidney, we can perform Percutaneous Nephrolithotomy (PCNL) under general anaesthesia. This involves making a small incision at the side of the body (less than 1cm in size) and inserting a small camera into the kidney to break and remove stones directly. With recent advances in technology and technique, the incisions have become smaller, which reduces bleeding risk during surgery and reduces pain after surgery.

The procedure was traditionally performed with patients in the prone (face-down) position, but now, we can usually perform it with the patient lying supine (face-up). This can reduce the duration of surgery and is also suitable for some patients who cannot lie face-down. It also facilitates combined procedures to improve the efficiency of stone removal and treatment. Most patients who undergo PCNL can go home after one to two nights’ stay in the hospital. For some patients with suitable stone size and good health, same-day discharge is also possible.

Prevention

We can all play an active role in preventing the formation of kidney stones. The best way to reduce the risk of kidney stone formation is sufficient water intake. The general recommendation is to take adequate fluids - about 2 litres of urine output per day - if there are no other medical problems restricting fluid intake. Depending on the person’s activity level, this may require more than 2 litres of water intake per day to achieve. Other lifestyle practices that can help to reduce the risk of kidney stones include:

• Exercise and weight loss
• Normal calcium intake in the diet
• Reduce dietary salt intake
• Reduce animal protein intake
• Avoidance of excessive foods/drinks rich in oxalate: coffee, black tea, chocolate, strawberry, spinach, etc.
  

Summary

Patients with kidney stones may present with flank and abdominal pain, blood in the urine or signs of urinary tract infection. If kidney stones are left untreated, they may lead to infection, kidney damage and pain. Treatment of kidney stones may include medication, shockwave treatment or minimally invasive surgery, with technological advances allowing for smaller incisions and facilitating shorter hospitalisation stays. Prevention of kidney stones can be achieved through adequate fluid intake and adjusting dietary intake.