Patient Guide

Urinary stones

WHAT ARE URINARY STONES

TThe function of the kidneys is to filter waste chemical compounds from the body into the urine. Under certain conditions, the chemicals (such as calcium, oxalate, phosphate, uric acid and others) in the urine may crystallise and combine to form urinary stones. Urinary stones may block urine flow and affect the function of the kidney.

Image via Mayo Clinic.

CAUSES

The risk of urinary stone disease is increased when there is:

  • Diet
    • Low intake of fluids
    • High intake of foods rich in salt (sodium)
    • High intake of foods rich in purine and oxalate

Hereditary

  • Family history of kidney stones

Medical

Individuals with medical conditions are at increased risk of developing kidney stones.

  • Hypercalcemia
  • Gout
  • Renal tubular acidosis
  • Chronic diarrhoea
  • Bowel disorders

Anatomical

  • Structural abnormalities in the urinary system leading to obstruction of urine

SYMPTOMS

Not all individuals with urinary stones will experience any symptoms. Common symptoms of a kidney stone include:

  • Cramping pain which radiates from
  • around the kidney to the lower abdomen
  • Painful urinary urgency
  • Blood in the urine (haematuria)
  • Recurrent urinary tract infections (UTI)

DIAGNOSIS

Imaging of the urinary tract could be done via:

  • X-ray
  • Ultrasound
  • Intravenous urogram (IVU)
  • Computerised tomography (CT) scan

Additional urine and blood tests may need to be done to exclude infection and impairment of kidney function and also to look for causes of stone formation.

DID YOU KNOW …

Urinary stone disease is a relatively common condition thought to affect 15% of the population and with a slowly increasing trend.

After treatment, there is a 25 to 50% chance of recurrence within five years. Thus, in many cases, urinary stone disease is a chronic condition.

Reference: Tan, Y. (2014, October). Preventing Kidney Stones. GP BUZZ, 10-13

TREATMENT

Treatment may vary depending on the stone location, size, number and patient factors such as age and fitness.

  • Observation and Medical Therapy (Dissolution/Medical Expulsion Therapy)
  • Extacorporeal Shock Wave Lithotripsy (ESWL) Involves focused shock waves that passes through the body to hit the stones. The fragments are then passed out in the urine. It is best suited for smaller stones high up in the urinary system.
  • Ureteroscopic Lithotripsy (URS)
  • Retrograde Intrarenal Surgery (RIRS)
    Both involve minimally invasive surgery to treat stones in the ureter. A narrow scope inserted through the urethra, bladder and up the ureter to reach the stone. There is no skin incision. Laser is then used to fragment the stone and the fragments are removed. An internal ureteric stent (DJ stent) may sometimes be inserted during the surgery.
  • Percutaneous Nephrolithotomy (PCNL)
    This procedure is suitable in the treatment of large kidney stones or for patients with abnormal kidneys thus making other treatment options unsuitable. This is done under general anaesthesia with a small incision in the back for insertion of a tube into the kidney. Through the tube a scope can be inserted to fragment and remove the stone.
  • Cystolitholapaxy
  • Laparoscopic/Open Surgery

PREVENTION

  • Adequate water intake (Applicable to everyone)
  • Reduce salt intake
  • Depending on your condition, your doctor may request for you to reduce intake of particular type of food
    • High-Oxalate Foods e.g. Spinach, peanuts, chocolate, black tea, sweet potatoes
    • Medium-Oxalate Foods e.g. Celery, green pepper, raspberries, strawberries, grapes, liver
    • High-Purine Foods e.g. Red meat, organ meats, shellfish

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