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Urinary Stones

There is present of aggregation of crystals made out of calcium and other minerals in the urine form stones that may cause pain, bleeding or infection when they block the urinary tract especially in the renal pelvic, ureter and bladder neck. As Singapore is a hot, tropical modern country with fast pace stressful lifestyle, urinary stone disease is common. It generally affects more males than females, between the ages from 35 to 60. Recently, the stone disease is also commonly seen in patients with a sedentary lifestyle and this may be related to their lifestyle and eating habits.

Urinary stones may present itself in many different ways.

Location of stones

Most of the stones arise from the kidney and drop from the kidneys to the ureter or bladder. Bladder stone disease used to be a disease of third world countries, especially in children with low protein intake. It can also form in developed countries like in Singapore but Nevertheless, most of the stones are mainly located at the kidneys and ureters.

Types of renal stones

There are several types of renal stones. The most common types are:

  • calcium mixed stones include the calcium oxalate and calcium phosphate stones due to poor water consumption

  • uric acid stones usually associated with gout.

  • triple phosphate stone, usually associated with the infection of urine or diabetes



The causes of renal stones are multi-factorial. There are certain risks factors that one needs to consider when discussing the causes of stone disease. The following are the risks factors for stone:

  • Hot climate with hard labour work

  • Prolonged immobilization

  • Chronic urinary retention with obstruction at the kidneys

  • Certain dietary habits, especially related to foods with high-oxalate, high salt and high-uric acid e.g. peanuts,

The causes of the renal stone are generally related to less water consumption. An increase in chances of calcium-related minerals precipitating within the kidneys’ collecting system and with stasis generally leads to stone formation.


Common Problems

If the stone is in the kidney, colic pain at the loin. If the stone is in the ureter, the stone will be at the loin but radiating to the groin. If lower, the stone might be in the lower end of the ureter and occasionally, the pain may be referred to the testes. The other urological complaints like haematuria.

The other complaints are related to complications of the renal stones and these are:

  • Infection e.g. fever, chills and rigors with haematuria

  • Obstruction with deteriorating renal function

  • Other rare complications, including cancer formation

Do all stones require treatment?

Not all stones require treatment. All renal pelvic, urethra and bladder calculi should be treated if they are causing symptoms, obstruction and complications related to the bladder or kidney except when the patient is very unfit.


There are three principles that relate to the prevention:

  • Drink more water

  • Change in diet, specifically to consume foods with less salt, uric acid and urate (like peanuts, beer etc)

  • Do not hold urine

  • Visit a doctor as soon as you have stone-related symptoms (especially when you are at high risk)


The treatments of the renal stone disease are mainly divided into following:


No treatment needed, if this stone is small and less than 5 mm in size. Even if it is treated, the stone may not pass out at all. A stone that is located at one end of the calyx usually will not cause any symptoms. Nevertheless, the patient needs to be followed up with regularly (at least once in 2 years) to review the size of the stone and the potential problems that it may cause.

Medical treatment

Medical treatment is usually indicated if the nature and type of the stone can be determined before treatment, and by adjusting the pH of the urine, the stone can be treated, and the residual stone can be treated by other means. The time taken for this treatment is longer. As a result, the acute phase or stone complications may not be suitable for this treatment.

External corporal shock wave therapy (ESWL)

Extracorporeal shock wave lithotripsy (ESWL) is one of the common modalities for treatment for upper urinary tract stone. It is indicated for small kidney stone (<2cm) and non–obstructive upper ureteric stones. However, ESWL may not be suitable for stones causing significant obstruction, infection or gross haematuria. The other limitation for ESWL is unknown nature of the stone for shockwave, hence the patient may require second or third treatments.

This seems to be the only treatment for patients which may not be suitable for surgery or endoscopic treatment. The patient may need to be co-operative, so as not to shift during blasting.

Generally, ESWL is done as an outpatient procedure and the patient is given sedation when blasted. The bowel needs to be prepared before the blasting.

The side effects or/and complications for this treatment are back pain from blasting, some skin blister due to the blasting, blood in the urine due to shock wave to the kidneys and occasionally infection and sepsis especially when the stone is infected without antibiotic coverage.

Endoscopic treatment

There are a few routes for endoscopic treatment for urological stones:

  • Through the urethra
    This is the commonest route for endoscopic treatment for stones in the bladder, in the distal and middle part of the ureter.​

  • Through the loin into the kidney – percutaneous nephrolithotomy
    This procedure is done under general anaesthesia and will insert a percutaneous tube to the back. Patient will needed to stay for 2 days. The actual term is percutaneous nephrolithotripsy (PCNL). A tract is created posteriorly at the loin (nearest to the kidney), and it is dilated so that a nephroscope can be inserted to the kidney to fragment the stone by ultrasound or laser which will be sucked out or retrieved. A tube is inserted for drainage and required to stay in the hospital for 2-3 days. Before the operation, patient will be cover with antibiotic.

    The complications of these procedures may included sepsis due to infected stone, bleeding injury to colon due to the initially puncture.

Open Surgery

This is not a common form of treatment as open surgery is usually required for big stones (>4cm) or complicated stones where the patient may require multiple episodes of treatment for the stone to be fully cleared. It is done through the loin in the retro-peritoneal way which is close to the kidney. The complication of this surgery is injury to the surrounding organs like the intestine and the big vessels and may damage the nephrons.



Disclaimer: This is not a guide to self-diagnose. We encourage to seek urologist advice further.

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