Kidney Stones Causes
A kidney stone is a solid mass of certain substances that form in kidneys or urinary tract. The substances that form stones normally pass through the urine, but they can become highly concentrated when enough urine volume is not there, and crystalize to form hard masses. Typically, the stone-forming substances include calcium, oxalate, uric acid, phosphate, and rarely cystine and xanthine.
The size of kidney stones usually ranges from a sand grain to the size of a chickpea. They can become as large as golf balls. Smaller stones may pass through the urinary tract with time, but they can cause significant pain. Depending on the size and location of kidney stones, pain may vary. Larger stones may get trapped in the ureters, the tubes that carry the urine from the kidney to the bladder. This keeps the urine from exiting the body, causing urinary symptoms, such as severe pain or bleeding. Stones that don’t pass on their own need to be removed with surgery. The treatment option is determined on the basis of the size of the stone, location, number of stones, and other factors such as shape, type of substance, and patient’s individual preference. Mainly, there are four types of kidney stones, namely, calcium oxalate or calcium phosphate, uric acid, struvite, and cystine.
It is advisable to consult a urologist as soon as you notice the symptoms of kidney stones. The doctor will conduct some tests to determine the condition, including blood, urine, and imaging tests. Decisions about treatment are based on the results of these tests. The cost of kidney transplant operation in India mainly depends on the type of treatment option opted.
Here are some causes of kidney stones:
1. Dehydration
A major risk factor for all kinds of kidney stones is the lack of water in the body. People who are at risk of having kidney stones should pay attention to their water consumption and stay hydrated. Studies have shown that drinking 2 liters of fluid per day contributes to the reduction of stone recurrence by about half. Dehydration can lead to stone formation because water is required to make urine to dilute the waste products filtered in the kidney. When enough water is not available, these products can concentrate to form stones. As a person loses some fluids through sweat and breathing, they should aim to drink about 10 cups daily. You can include citrus drinks such as lemonade or orange juice, as the citrate can help block stones formation.
2. Certain foods
The most common type of kidney stones is made of calcium and oxalate when they stick together in the kidneys. Oxalate is found in healthy foods and vegetables and people at high risk of forming stones must limit high-oxalate food intake. These foods include spinach, grits, bran cereal, to name a few.
Oxalate rich foods such as nuts, spinach, potatoes, tea, and chocolate, can increase the amount of oxalate in the urine. These should be consumed in moderation.
3. Lack of calcium
Calcium stones, either calcium oxalate or calcium phosphate, are the most common type of kidney stones. Surprisingly, a randomized clinical trial showed that people with calcium kidney stones should not reduce dietary calcium. It is advisable to consume the recommended daily dosage of calcium, which is 1,000 mg/day for women below the age of 50 years old and men below the age of 70, and 1,200 mg/day for women above 50 years of age and men over 70.
The concept behind this is that calcium will bind to oxalate in the intestine and prevent absorption, which will result in less urine and stone formation.
4. Sodium
We mainly get this through table salt. Sodium may raise the chances of forming several types of kidney stones. Limit sodium-rich products such as salty snacks, packaged meats, canned foods, and other processed foods.
5. Animal protein
Kidney stones can also form when the urine gets too acidic. Red meat and shellfish cause a rise in uric acid in the body. It gets collected in the joints and causes gout or form stones in the kidneys. Animal protein raises the urine’s calcium level and lowers the amount of citrate, which can cause stones.
6. Diseases
Calcium phosphate stones, though less common than calcium oxalate stones, can be caused due to hyperparathyroidism (overproduction of parathyroid hormone), renal tubular acidosis (a kidney disease in which acid builds up in the body), and urinary tract infections.
7. Uric acid
Most uric acid stones are not caused by too much uric acid, rather than urine is too acidic. Due to this, normal levels of uric acid can get dissolved into the urine where it crystallizes into stones. Balancing the urine pH, using medication potassium citrate, lowers the risk of uric acid stone formation. This may also help dissolve the existing stones. Sodium bicarbonate is also used for alkalinization of the urine.
8. Infection
Struvite stones, made of magnesium ammonium phosphate, usually form in alkaline urine. The bacterial infection is the most common cause of struvite stones which increases the urine pH to neutral or alkaline levels. Acetohydroxamic acid (AHA) reduces the pH and ammonia levels in the urine and helps dissolve stones.
9. Congenital diseases
Genetic conditions, such as cystinuria is caused by high levels of cystine, an amino acid, in the urine, resulting in the formation of kidney stones. Cystine stones can be managed by maintaining hydration and medications to adjust the pH of the urine.
10. Certain medications
Some drugs may elevate the risk of kidney stones. Drugs that can increase the chances of developing kidney stones:
- Diuretics (water pills)
- Calcium-based antacids
- Crixivan® (for treatment of HIV infections)
- Topamax® and Dilantin® (treatment of seizures)
- Antibiotics such as Ciprofloxacin and Ceftriaxone
- Conditions that affect calcium absorption in the body. These include inflammatory bowel disease, gastric bypass surgery, and chronic diarrhea.
- Risk factors such as age, genetics, and prior history of kidney stones. Generally, kidney stones are observed for people between the ages of 30 and 50 years.