By DR JC (CORNE) VAN GRAAN – Urologist; MBChB(Pta) , M.MED(UROL) FC UROL(SA)
Understanding kidney stones, how to treat them and preventative steps to avoid more recurrence.
Our kidneys play a vital role in eliminating waste products from the body. These waste products are excreted as urine via the ureter into the bladder and then eliminated from the body. Excessively high levels of waste products such as calcium oxalate or uric acid, which can occur for a variety of reasons, can overload the urine.
Over time this can result in the formation of kidney stones that can lead to blockages and severe pain.
According to Dr. Corne van Graan (Urologist at Cure Day Hospitals Wilgeheuwel), “A kidney stone is an abnormal formation of crystals and salts in the kidney, which over time grow in the collecting system of the kidney.“ The stones later break off from the kidney into the ureter towards the bladder. This leads to blockage of the urine between the kidney and bladder, which causes the immense pain a patient experiences when passing kidney stones”.
So how does this happen? Your urine naturally consists of a high concentration of salts and waste products. In some people, these salts crystalize and then form stones. Because the urine is supersaturated with these salts, this will lead to the stones growing in size over time. Although the exact amount of time it takes for a kidney stone to form is not known it is estimated to develop over several months, or possibly even years, he says.
Kidney stones are rarely a sign of kidney disease and stone formation. It is in fact uncommon in people with poorly functioning kidneys. Kidneys stone formation in most adults is not thought to be an inherited condition, even if several family members have had stones. According to the Canadian Urological Association, children with kidney stones, however, are more likely to have an inherited risk. Some children have a severe stone disease that require thorough investigation and follow up.
Between 10 – 15% of the general population develop kidney stones, and while anyone can get them, a number of risk factors can increase your chances.
KIDNEY STONE RISK FACTORS:
- Men are more prone to develop them than women
- There is a higher risk in hot, arid or dry climates
- Higher prevalence in summer
- Higher risk in obese patients
TYPES OF STONES
There are several different types of stones defined by different constituents depending on the individual’s diet, ability to metabolise particular elements from food or even changes in the functions of the bowels or kidney. Calcium-based stones are the most common type, such as those containing calcium oxalate or calcium phosphate.
About 7% kidney stones are uric-based, which is a by-product of the breaking down of purine-rich foods such as meat and alcohol. People who suffer with gout may be more prone to these types of stones.
Another 7% of stones are Struvite stones, which can occur in associations with certain bacterial infections of the urine.
DETECTING KIDNEY STONES
“For children or young people with stones, multiple stone formers, or those with a strong family history, it is possible to screen for individual risk factors where your doctor will look at the salt levels in urine and in the blood and then try and determine where the underlying problem is.
“It is also possible to detect stones before painful symptoms are experienced. This is done through a urine test to detect small crystals in the urine. Stones can also be found incidentally on sonar or a CT-scan, “Dr van Graan outlines. “Small uric acid stones can be dissolved by alkalizing the urine before painful symptoms occur.”
WHEN KIDNEY STONES STRIKE
A kidney stone develops over a matter of months or years in the kidney. Later it breaks off from the kidney into the ureter and literally blocks the flow of urine from the kidney to the bladder. “ This is when patients experience tremendous pain,“ he points out.
“ Symptoms can be colicky in nature as the pain comes and goes.”
- Smaller stones less than 4mm that are close to the bladder can usually pass spontaneously with a combination of pain medications, muscle relaxants and plenty of fluids.
- Bigger stones, however, can be so painful that a patient ends up in the emergency rooms. A doctor in the ER should complete a good history and examination and will usually do a urine dipstix test to check for blood. A CT scan will then confirm the diagnosis. The location and size of the stone as well as available equipment will dictate the course of treatment.
- Kidney stones that are bigger or closer to the kidneys could require endoscopic surgery, where the stone can then be broken up into smaller fragments with a laser. Stones that are lodged in the kidney can be treated with a procedure called ESWL( extra Corporeal shockwave lithotrispsy) which are shockwaves that can break up the stone.
Complications of kidney stones in the ureter can occur if you have an infection in the upper urinary tract due to the stone blocking the passage of the infected urine. This can lead to renal sepsis. For this reason, a kidney stone with blockage and an infection should be treated as an emergency.
STONE PREVENTION STRATEGIES
As much as 50% of stone formers, will develop a second kidney stone within 10 years of the first one and as many as 75% within 20 years, according to the Canadian Urological Association.
STOP STONE RECURRENCE
So what can everyone safely do to prevent kidney stones and stone recurrence?
- Drink up: Increase fluid intake to at least 3000ml per day to ensure a urine output of more than 2 liters per day. And it doesn’t all have to be plain water. Recent evidence suggests that sparkling water offers increased protection against stone formation compared with still water. Citrus juices such as lemonade are also considered good complimentary options to water that help increase urinary nitrate levels.
- Cut out caffeine: a number of studies point to caffeine as being a culprit in increasing the risk of stone recurrence in calcium stone formers by increasing the excretion of calcium.
- Hold the salt: avoiding salty foods and restricting salt intake is widely-recommended as an important element of dietary prevention.
Dr van Graan points out that effective prevention needs to be tailored on a case by case basis after a full workup to determine the underlying causes. A high intake of meat, fish and poultry increases the risk of stone formation, as protein intake increases urinary calcium, oxalate and uric acid excretion so it may be required to limit protein intake for those with uric acid stones as well as calcium stone formers.
Those with calcium-based stones should not reduce their intake of calcium without consulting their doctor, as it is an essential element as part of a healthy balanced diet and helps prevent osteoporosis in later life. Instead, your medical practitioner will advise on avoiding large amounts of oxalate-rich foods such as spinach, bets, chocolate, nuts and tea. Avoiding highly daily doses of vitamin C is also recommended. Doctors suggest monitoring with an x-ray or ultrasound of the kidneys on an annual basis is prudent if you have previously had a kidney stone.