A man in his 60s suddenly felt discomfort in his lower back, and soon after he was so sore that it was difficult for him to stand up. When he went to the hospital emergency room, he found out that it was because of kidney stones. The man had a history of kidney stones in the past. However this time, the doctor told him that his kidneys had also deteriorated quite a bit.
What are the causes of various stones such as kidney stones and urinary tract stones? Why are some people more prone to developing stones? In this article, we will outline one simple way to prevent and help expel stones from your body.
Urinary Tract Stones Cause Many Problems
Most of the liquid that people consume every day is processed by the kidneys into urine, then flows into the ureter and bladder, and is finally excreted through the urethra.
Stones may form if the urine produces crystal deposition during the process of urination. Stones can appear in different places, forming kidney stones, ureteral stones, bladder stones, and urethral stones, which are collectively referred to as urinary tract stones.
People usually do not feel and do not know they have stones in their bodies without going to the hospital for a checkup. However, once the stones cause irritation or obstruction, they can trigger different symptoms depending on their location:
Kidney stones: Most urinary tract stones start with kidney stones, which can cause severe back pain and blood in the urine (hematuria) when they move. Pain can also occur if a kidney stone falls down and gets stuck in the ureter, causing edema.
Yu Chen, a urologist and assistant professor at Chang Gung Memorial Hospital in Taiwan pointed out that stable kidney stones do not necessarily need to be treated. Regular doctor visits can help to track the size of the stone and see whether it has caused an infection, blood in the urine, or pain. Sometimes, patients with kidney stones may not see obvious blood in their urine, but only feel pain, so they mistakenly think that they are injured; sometimes it’s hard to tell if the pain is caused by an injury to the lower back or a stone, so it’s best to seek medical attention when the pain is unbearable.
Ureteral stones: Most stones in this area are caused by kidney stones that fall out and become blocked. Ureteral stones not only cause severe pain in the lower back, but the pain may also radiate to the scrotum and groin. Such pain may even affect the peristalsis of the intestines, causing stomach discomfort and bloating.
Both kidney stones and ureteral stones will cause severe pain. Chen emphasized that its pain index is “second only to childbirth.”
Bladder stones: The bladder has more space than the kidney and ureter, so pain from bladder stones is only occasional. Most of the time, there will be a feeling of fullness in the lower abdomen, and symptoms of hematuria and frequent urination may occur. Stones have room to move in the bladder and tend to roll around, causing sensitive bladder and frequent urination.
Urethral stones: The urethra is a tube that connects the bladder to the outside of the body. If small stones get stuck in the urethra during the excretion process, it will cause symptoms such as hematuria, pain, weak urine stream, and irregular urination.
The degree of pain caused by urinary tract stones also depends on the size of the stones. Chen explained that the bigger the stone, the less painful it is, as it doesn’t move around; the smaller the stone, the more painful it is.
A small number of patients with kidney stones may experience back soreness and pain, but some patients can endure the pain very well, and the stones become larger over time. As a result, it cannot be treated in simple ways, and may even require surgery with a higher risk of treatment.
4 Common Causes of Stones
Calcium stones are the most common type. Tzung-Hai Yen, director of the Toxicology Department of Linkou Chang Gung Memorial Hospital in Taiwan, said that more than 80 to 90 percent of the total number of patients had calcium stones, mainly calcium oxalate and calcium phosphate ones.
Stones can be caused by many factors, but the following are the most common:
- Genetics and family history
If your parents or relatives have a history of stones, you are more likely to develop stones yourself.
Tzung-Hai Yen said, “Some patients have family members who have kidney stones, and their offspring are also more susceptible to it.” Genetics is one of the causes. Another factor is whether the lifestyle and eating habits of family members are alike.
- Water quality
Chen Yu found that water from the environment is also related to the formation of stones. He used Taiwan as an example. According to statistics, the number of patients with stones in Taoyuan City is higher than that in Taipei City. This is because the water used in Taipei comes from the Feitsui Reservoir, while Taoyuan uses the Shihmen Reservoir. The water quality of the Shihmen Reservoir is harder.
Hard water also indicates more calcium ions. When ingested into the body, they’re more likely to deposit and form stones.
Chen suggested that people who live in areas with hard water can choose to install a better water filter to make the water softer. For the same reason, it is recommended to drink purified water for patients with a history of urinary tract stones.
- Dietary habits
“Patients getting kidney stones should also watch their eating habits,” said Yen.
People who do not like drinking much water, prefer eating salty food and meat, and often consume alcohol are more prone to getting calcium oxalate stones.
People who like to eat high-purine foods, such as organ meats and seafood, are more prone to uric acid stones, as purine is metabolized into uric acid. They are also prone to gout due to high levels of uric acid in their body.
Some people may also take too many dietary supplements, such as calcium, vitamin C, or vitamin D, which may cause stones.
Yen explained that vitamin D increases the absorption of calcium and phosphorus in the gastrointestinal tract. Therefore, consuming too much vitamin D can lead to hypercalcemia and kidney stones. Oxalic acid is produced when vitamin C is metabolized in the body. Supplementation in high doses increases the concentration of oxalic acid in the urine and increases the risk of developing stones.
Chen pointed out that in general, it takes a long period of time for water quality and dietary factors to cause the formation of stones.
- Diseases and infections
Gout, diabetes, obesity, malabsorption, prostate hyperplasia, and metabolic disorders such as distal renal tubular acidosis, hyperparathyroidism, and certain genetic diseases can also cause urethral stones.
Medical research has found that kidney stone patients share comorbidities which include obesity, diabetes, gout, and other metabolic disorders. The diets of these patients are mostly high in sodium, oil, sugar, and purine.
Bladder stones are likely to accompany prostate hyperplasia because patients with prostate hyperplasia tend to have symptoms of intermittent urination, weak urine stream, and urinary retention. When a person has excess urine left in the bladder every time he or she urinates, crystals can deposit in the bladder and form bladder stones. Chen pointed out that this is very common.
Any bacteria entering the urinary tract can cause urinary tract infections, and urinary tract infections caused by Gram-negative bacteria (GNBs) are prone to stone formation.
Distal renal tubular acidosis is a major risk factor for struvite stones. Other types of voiding dysfunction, such as congenital renal outlet stenosis, ureteral stricture, congenital urinary tract stricture, and prostate hyperplasia, can also cause infection.
Yen mentioned that patients with stones are mostly male. Women develop stones mostly due to endocrine problems, such as primary hyperparathyroidism. The role of the parathyroid hormone in the kidneys is to retain calcium and excrete phosphorus. The disease will produce too much parathyroid hormone and eventually lead to the formation of kidney stones.
Other factors include weather differences. In the hot and sweat-inducing summer, if you do not replenish water in a timely manner, urinary tract stones are very likely to form.
The Easiest Way to Prevent Stones
If the factors causing urinary tract stones are caused by congenital structural problems, endocrine abnormalities, or diseases, surgery or medication is usually required to solve the root cause. For stones caused by other factors such as family history, food, or water sources, there are simple ways to prevent them. The easiest way is to drink more water.
- Drink a lot of water
Urinary tract stones of any composition can be prevented by drinking a lot of water.
“This is the best way,” said Chen. This is because stones grow slowly from crystals, before turning into larger stones. The inner diameter of the ureter is about 0.5 centimeters. If the stone is smaller than 0.5 centimeters, drinking a lot of water may flush the crystal out of the body.
Similarly, if the patient’s urinary tract stones are found to be less than 0.5 centimeters, and there is no blockage, infection, blood in the urine or pain, all they need to do is drink more water and follow up with their doctor regularly.
A 2015 meta-analysis found that every 500-milliliter increase in water intake was associated with a significantly lower risk of kidney stones. The 2020 Cochrane Review further validated that people who have had stones and drank a lot of water were less likely to have stones recur in their bodies, and even if they do recur, it will take longer.
To prevent urinary tract stones and stone recurrence, it is recommended to drink 2.5 to 3 liters of water per day.
- Consume more citric acid
Citric acid binds with calcium in the urine and reduces the concentration of calcium ions in it, thereby lowering the incidence of kidney stones. Citric acid also binds calcium oxalate crystals, preventing them from forming stones in the body.
You can add more citric acid to your diet by consuming more lemons, oranges, grapefruits, apples, and other fruits rich in citric acid. Alternatively, you can add lemon slices to water, and drink grapefruit, apple, and orange juices in moderation to reduce stone formation.
- Eat a low-sodium and moderate-calcium diet
A high-sodium diet increases calcium in the urine, which in turn combines with oxalic acid and phosphoric acid to form calcium oxalate and calcium phosphate stones. Therefore, patients with stones are advised to follow a low-sodium diet.
You may also take calcium supplements, as long as it is done in moderation.
Yen pointed out that many studies have shown that a low-calcium diet actually increases the formation of kidney stones. This is because when there is not enough calcium in the gastrointestinal tract to combine with the oxalic acid from the diet, the concentration of oxalic acid in the body will rise, increasing the excretion of oxalic acid in the urine, which increases the risk of developing stones. Similarly, calcium tablets must be taken with meals to avoid an increased risk of stone formation.
Chen believes that people who have no history of genetic disease or stones and have osteoporosis can take calcium supplements. For those with relevant medical history, additional calcium supplementation is not recommended; the consumption of tofu, dried tofu, and calcium tablets should be reduced because such people usually have enough calcium in their bodies and do not need additional supplements.
However, people who had urinary tract stones in the past are prone to recurrence. While following the diet described above may reduce the risk of developing stones, there is still a chance of recurrence.
Chen said that the recurrence rate is still 30 percent even after the stones in the body have been cleared. A 2016 study also found that people who had stones for the first time had a 50 percent recurrence rate within the first 5 years.
Furthermore, people who often develop kidney stones will also have their kidney function affected, leading to chronic kidney failure. Therefore, regular annual hospital visits for patients with urinary tract stones are recommended.
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Camille Su is a health reporter covering disease, nutrition, and investigative topics. Have a tip? [email protected]
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