Dr Palaniappan Sundaram, Senior Consultant, Department of Urology at Sengkang General Hospital (SKH), answers common questions about kidney stones (urinary stones).
Dr Palaniappan Sundaram, Senior Consultant from the
Department of Urology at
Sengkang General Hospital (SKH), a member of the
SingHealth group, answers frequently asked questions about kidney stones, also known as urinary stones.
FAQs about kidney stones (urinary stones)
1. Are kidney stones (urinary stones) preventable?
Kidney stones (urinary stones) tend to recur in about 50 percent of cases, so prevention is your best course of action. To reduce your risk of developing it, ensure:
Adequate water intake. Drink enough water (about 2.5 litres of water) a day or enough water to produce light and clear urine.
Sufficient calcium intake. In the past, people who form calcium stones were told to avoid dairy products and other foods with high calcium content. Recent studies have shown that foods high in calcium, including dairy products, may help prevent calcium stones. Older women taking calcium supplements to prevent bone loss should continue to do so.
Reduce intake of oxalate-rich foods. Foods that have medium amounts of oxalate may be eaten in limited amounts.
High-oxalate foods include spinach, rhubarb, beets, peanuts, soybean crackers, chocolate, black tea and sweet potatoes.
Medium-oxalate foods include grapes, celery, green pepper, raspberries, strawberries, marmalade and liver.
Control vitamin D intake. You may be told to avoid food with added vitamin D and certain types of antacids that have a calcium base.
Restrict meat intake. If you have highly acidic urine you may need to eat less meat, fish, and poultry as these foods increase the amount of acid in the urine.
2. How are kidney stones (urinary stones) formed?
Kidney stones form as a result of urine with a high concentration of certain chemicals (such as calcium, oxalate, phosphate, uric acid and others) and a low concentration of substances that stop kidney stone formation (urinary inhibitors such as citrate and magnesium).
Urinary tract infections (UTI), kidney disorders such as cystic kidney diseases, and certain metabolic disorders are linked to stone formation.
Calcium oxalate stones may also form in people with chronic inflammation of the bowel or have had an intestinal bypass operation, or ostomy surgery.
The most common type of stone (>80% of all stones) contains calcium oxalate or calcium phosphate.
A less common type of stone, caused by infection in the urinary tract, is called a struvite stone. Other rarer stones include uric acid stones (about 10% of stones) and cysteine stones.
2. Who is at risk of getting kidney stones (urinary stones)?
Stones occur more frequently in men, and most commonly between 40 and 70 years old. Other risk factors include:
Obesity has been associated with >50% higher risk of stone formation.
family history of kidney stones is associated with a higher risk.
lack of fluid intake leads to concentration of salts in the urine, increasing risk of stone formation.
Certain diets high in oxalate (nuts, long beans, chocolate), high in purines (red meat, organs, seafood)
Have kidney stones before: An individual with a diagnosed kidney stone has a 50% risk of developing another stone within the next 10 years.
Certain medical conditions: Diabetes (Type 2 Diabetes Mellitus), metabolic syndrome,
hyperparathyroidism, renal tubular acidosis, gastrointestinal diseases (including
inflammatory bowel disease, malabsorption, bariatric surgery, previous intestinal resections). Known conditions associated with urinary tract obstruction can also increase the risk of stone formation.
Use of certain medications such as HIV medications (indinavir).
3. What are the common symptoms of kidney stones (urinary stones)?
The first symptom of a kidney stone is severe pain, which begins suddenly when a stone moves in the urinary tract and blocks the flow of urine.
Typically, you will feel a sharp, cramping pain in your back and side, and around the area of the kidney. The pain may shift to the lower abdomen later on. Sometimes, you may also experience nausea and vomiting.
As the stone moves and the body tries to push it out, blood may appear in your urine making the urine pink. As the stone moves down the ureter closer to the bladder, you may feel the need to urinate more often or a burning sensation during urination.
If fever and chills accompany any of these symptoms, an infection may be present.
4. How are kidney stones (urinary stones) treated?
Most small kidney stones can pass through the urinary system with plenty of water - six to eight glasses a day - to help move the stone along.
For larger kidney stones, the following treatment options are available:
a) Medical therapy
Certain medications may help prevent calcium and uric acid stones by controlling the amount of acid or alkali in the urine which are key factors in crystal formation.
The medicine allopurinol may also be useful in some cases of hyperuricosuria where the chemical uric acid is secreted in large amounts in the urine.
b) Surgical treatment
Extracorporeal shock wave lithotripsy (EWSL), done as an outpatient procedure, uses shock waves to break urinary stones into fragments, which are then passed out in the urine over the next few days. This non-invasive and safe procedure, however, may require more than one session.
Percutaneous nephrolithotripsy (PCNL) is a minimally invasive keyhole operation. A small hole is made in the body to allow a scope to pass into the kidney. The urinary stone is broken up and removed through this passage.
Ureteroscopic stone removal involves passing a small scope through the urethra and bladder into the ureters and kidneys. The urinary stone is then broken up and removed.
Read on to learn about a study conducted to determine if
drinking a type of sparkling mineral water could prevent kidney stones (urinary stones).
Ref: I23 (ed)
Other articles you may be interested in:
7 Ways to Prevent Urinary Tract Infections (UTI)
Urinary Incontinence in Women: Types and How to Treat
Blood in Urine (Hematuria): When Is It a Concern (and When Is It Not)
What are Pelvic Floor Disorders and Where to Go for Treatment
Urinary Incontinence in Seniors
Faecal Incontinence Treatments (Non-surgical and Surgical)