Quite often, kidney stones are not associated with any symptoms at all and are only discovered accidentally after an ultrasound or CT scan is performed to investigate an unrelated complaint. However, in many cases stones cause severe symptoms requiring emergency treatment.
Common symptoms include:
- Pain (renal colic). The pain of kidney stones has been described as one the most intense pains possible and has been compared to the pain of childbirth. It occurs when a stone blocks the kidney, usually by moving out of the kidney into the tube that drains urine out of the kidney (the ureter). The pain may be cramping or sharp and is located in the side and upper back, moving down to the groin. It may be associated with vomiting.
- Blood in the urine
- Fevers associated with pain in the side
If a kidney stone is suspected, standard blood, urine and radiology tests are necessary to determine the size and position of the stone and to detect any damage the stone may be causing. Once the immediate episode has been dealt with, further tests may be required to help determine why the stone formed in the first place.
- Full blood count, creatinine (to determine kidney function), calcium, uric acid
- Later, parathyroid hormone tests and possibly other blood tests may be required
- Urine cultures (to detect any sign of infection)
- Later, 24 hour urine analysis to determine the amount of calcium, oxalate, uric acid and other substances in the urine
- Plain abdominal X-Ray, CAT scan
- If the stone is retrieved, the chemical composition is determined
There are no absolute rules governing the treatment of kidney stones. Treatment decisions will be based on the following:
- The size of the stone
- The position of the stone (ie: is it in the kidney, or has it come down into the ureter?)
- The likely type of stone (some clues can be gleaned from X-rays and CAT scans)
- Whether the patient is in uncontrollable pain (emergency treatment is needed)
- Whether an infection is also present (emergency treatment may be needed)
Quite often, stones can be managed conservatively. This is especially true for small painless stones in the kidney. It is also true for small stones in the ureter that are no longer causing pain. These stones often pass with the help of certain medications, which will be discussed with you. The likelihood that a stone lodged in the ureter will pass without the need for treatment depends largely on its size.
|Stone Size||Rate of passage within 4-6 weeks|
We are now fortunate to have a number of technologies available to cater for stones that need to be treated. These include the holmium laser, ultrasonic shock wave lithotripsy, minimally invasive percutaneous surgery and laparoscopic surgery.
The following treatment modalities may be used. Detailed information about each of these is included in the section entitled Procedures and Treatments
ESWL (Extracorporeal Shock Wave Lithotripsy).
Ideally suited to stones 1-2cm in diameter, composed of calcium oxalate and located in the kidney
When a stone is blocking the ureter and causing pain or infection, often the safest initial treatment is to insert a ureteric stent. This relieves the blockage and makes definitive stone treatment by ureteroscopy or ESWL safer.
Ureteroscopy and holmium laser stone destruction.
Ideally suited to stones within the ureter. Sometimes, a ureteric stent is inserted after the procedure, to avoid blockage of the ureter that can be caused by swelling after surgery. Quite often a ureteric stent is required before a ureteroscopy is possible. This is because the ureter is a very narrow and fragile tubular structure that may be damged by the passage of a telescope into it. A stent allows the ureter to relax and dilate, making the subsequent passage of a ureteroscope safer and easier.
Percutaneous Nephrolithotomy (PCNL).
Ideally suited to stones greater than 2 cm in diameter within the kidney
- Dissolution therapy. Stones believed to be composed of uric acid (and therefore not visible on a plain X-ray) may be dissolved without the need for surgery. Dissolution therapy involves a combination of:
- High water intake
- Reduction in foods rich in purines
- Alkalinisation of the urine (using Ural or bicarbonate)
- Medications to block uric acid production (Allopurinol)
Strategies to prevent stones will be discussed with you once the stone has been collected and any tests required to demonstrate why you have formed the stone have been completed.
Strategies that may be advised include:
- Maintaining a healthy water intake so that urine output is 2-3 litres per day and the urine appears clear.
- Reducing salt intake to 2-3 grams per day
- Increasing citrate intake (orange juice is a good source of citrate) and avoid cola drinks
- Take oxalate rich food in moderation (eg spinach, tea, nuts, chocolate, berries, rhubarb)
- Avoiding Purine rich foods (in uric acid stone formers) eg. Beer, alcohol, anchovies, sardines, liver, kidney, mushrooms, spinach and poultry. Limit animal protein to 200-250g per day.
- Maintain a healthy calcium intake
- Medications in selected cases. Examples include:
- Allopurinol (in uric acid stone formers)
- Thiazide diuretics (in those with high levels of calcium in the urine, including those who take calcium supplements for bone health. These drugs are often given along with potassium citrate supplements.)
- Penicillamine or Thiola (cystine stone formers)
- Potassium citrate 2-4 grams per day to alkalinise urine in patients with acid stones.
It is imperative that you attend scheduled follow-up visits. It is mandatory to ensure that any stone in the ureter has passed or has been removed before clearance can be given. Further tests may also be ordered to determine why you formed the stone and what treatment will be needed in the long term.