Kidney Stones and Chronic Kidney Disease

Kidney stones can also be called renal stones, renal calculi, or by the medical names nephrolithiasis and urolithiasis. All these names mean the same thing: there is a formation of hardened minerals in the kidneys or urinary system. In most cases kidney stones are formed because of a decrease in urine volume or increase in the minerals that form the stones in the urine.

About 1 in every 20 people will have a kidney stone in their lifetime. Three times more men will have kidney stones than women and they are more common in Caucasians than African Americans. Kidney stones are also more common in the summer than in the winter.

The renal stones can form in the area of the kidney that collects the urine, called the renal pelvis, the bladder (pouch that holds urine before it is released from the body) or the urethra (the tube that leads urine from the bladder to outside of the body). Kidney stones vary in size — from as tiny as a speck of sand to as big as a golf ball and, sometimes, even larger. While some kidney stones may pass through the urinary tract with little problem, there are times when a kidney stone causes great pain and cannot pass through the urinary tract without medical help.

What are kidney stones?

In most cases, kidney stones are formed when there is too little fluid (from dehydration due to lack of drinking or excess exercise), an overabundance of crystal-forming minerals in the urine, and/or lower-than-normal levels of the chemicals that breakdown these minerals in the urine. Minerals such as calcium, oxalate, uric acid, sodium, cystine or phosphate form into a solid mass that is the kidney stone. The kidney stone will either travel out of the body through the urinary tract or stay in the kidney, bladder or urethra.

Most of the time, the kidney stone will pass with little or no discomfort, but if the stone is large enough, or gets stuck somewhere along the way, you will have to take steps to have a doctor remove the stone.

It is important to find out the cause and type of renal stone so that the best treatment and preventative measures can be taken. If a person has a kidney stone once, the chances go up of having one again. Renal stones can cause an obstruction preventing your kidneys from being able to remove wastes. A kidney stone may also have rough or sharp edges that can cause damage and scarring in the kidney, which could lead to chronic kidney disease (CKD) and even kidney failure.

Symptoms of kidney stones

You may not know you have a kidney stone unless it causes pain, is large and blocks the flow of urine or is being passed. The most common symptom is severe, fluctuating pain that starts in the area where the kidneys are located, in the lower back or side under the ribs. Pain tends to move with the stone. If the stone stops, the pain may stop. Other symptoms include:

  • Bloody or cloudy urine that smells bad
  • Nausea and/or vomiting
  • Fever and/or chills
  • Burning, painful sensation when urinating

If you have any of these symptoms, please call your doctor. Taking care of kidney stones early can prevent serious complications, such as CKD or, in extreme cases, renal failure that would require dialysis or a kidney transplant to replace the function of the kidneys.

Types of kidney stones and how they are formed

There are four major types of kidney stones: calcium, struvite, uric acid and cystine.

  • Calcium kidney stones are the most common. About 80% to 90% of kidney stones are mainly calcium mixed with other minerals (typically oxalate or phosphate). Excess calcium the body doesn’t use is eliminated through the kidneys. This excess is usually flushed out in the urine. If the calcium is not flushed out, or if there is simply too much to dissolve, it can turn into crystals and join with other minerals to form a stone. Calcium stones often occur in people with high levels of vitamin D or overactive parathyroid glands. People with chronic kidney disease are more likely to get calcium kidney stones.
  • Struvite kidney stones typically form after a urinary tract infection. They are more common in women, who tend to have chronic urinary infections more often than men. Chronic urinary tract infections create enzymes that increase the amount of ammonia in the urine. This excess ammonia allows bacteria to grow more quickly helping to create the struvite stone. Struvite stones tend to be jagged or stag-horn shaped stones and can become rather large, which can cause damage to the kidneys.
  • Uric acid kidney stones are formed due to too much uric acid in the urine. When the acid level is high, crystals form and combine calcium and oxalate to make a kidney stone. This type of renal stone is more common in men. A diet high in animal protein can contribute to the amount of uric acid in the body. People with gout are at risk for uric acid stones.
  • Cystine kidney stones are rare compared to the other types of kidney stones because they are caused by an inherited disease. Cystine is an amino acid (building block of protein). Some people have a genetic condition called cystinuria that doesn’t let the kidneys reabsorb cystine into the blood. Cystine does not dissolve well in urine, so when left there it forms crystals that can grow into cystine stones. Most people with this condition are diagnosed at a young age and will be treated for this throughout their lifetime.

Treatment for kidney stones

It is important for your doctor to determine what type of kidney stone you have so he or she can figure out the best treatment and removal. This can usually be determined by evaluating a 24-hour collection of urine, or by examining a stone after it has been passed. Different types of kidney stones require different types of treatment.

There are several methods of renal stone removal; many don’t require surgery. You may even be able to pass a stone through your urinary tract by drinking lots of water (2 to 3 quarts a day, if you are not on a fluid-restricted diet). Renal stones that are too large to pass, or are causing bleeding or other damage, may require more aggressive treatment.

Some of the treatments for kidney stones include:

  • Shock waves that are sent directly to the kidney stone. Extracorporeal shock wave lithotripsy (ESWL) or sound waves is not an invasive treatment, so it doesn’t require surgery or a hospital stay. The patient lies on a water-filled cushion and the surgeon locates the kidney stone through X-ray or ultrasound. The low- or high-energy shock waves break the kidney stone into pieces small enough that you will be able to pass them in your urine. The procedure takes about an hour. ESWL can be painful so your doctor may give you a sedative or anesthesia. After the treatment you may experience bleeding in the urine, minor bruising on the back and abdomen or pain as the kidney stones passes.
  • Nephrolithotomy, or percutaneous (meaning “through the skin”) nephrolithotomy, is when the doctor makes a small incision in your back and removes the kidney stone using a nephroscope. The nephroscope is a tube inserted into the kidney. The stones are broken up with sound waves and then suctioned through the tube. Even though nephrolithotomy is less invasive than open surgery, it is still a surgery requiring anesthesia and a two- to three-day hospital stay. Nephrolithotomy is necessary if a renal stone is too big for EWSL, or if EWSL treatment doesn’t work. This is the recommended treatment for the stag-horn shaped struvite kidney stones. After surgery you may feel tenderness in the incision and kidney area. A catheter will be placed in the bladder for urine to flow out of the body and there will be a drainage port from the kidney to the outside of the back. These will be removed a day or more after the surgery.
  • Ureteroscopic kidney stone removal is a procedure that uses a scope passed through the bladder to remove a stone that is stuck in the ureter. The ureter is a tube that carries urine from a kidney to the bladder. The ureteroscope is a tool that goes up the bladder to the ureter and kidney to where the kidney stone is located. Sometimes, ultrasound (ultrasonic lithotripsy), lasers or electrohydraulic lithotripsy is used directly through the scope to shatter the kidney stone. This is usually an outpatient surgery performed under anesthesia.

How lifestyle choices can help prevent kidney stones

Because about half of all people who get kidney stones once will get them again, the best way to treat them is to prevent them from coming back. Prevention through changes in lifestyle, especially eating and exercise habits, is often the best method to avoid kidney stones or prevent a recurrence. Drinking about 2 to 3 quarts of water a day is usually recommended for someone with a history of kidney stones (unless on a fluid-restricted diet). Also, if you form calcium stones, your doctor may recommend reducing your intake of oxalate-rich foods such as nuts and nut butters, rhubarb, beets and beet greens, spinach, tea, chocolate, strawberries and black raspberries. Diets low in protein can help reduce the chances of developing some types of kidney stones.

Besides dietary adjustments, your doctor may prescribe medicines that help control the amounts of certain kidney stone-causing minerals from developing in the urine. Your doctor will recommend the best treatment after determining what type of kidney stone you have.

For some people, calcium kidney stones are caused by excessive production of hormones by the parathyroid glands. High parathyroid hormone levels can cause a release of calcium from the bones, and the excess calcium creates kidney stones. By having a surgeon remove one or more of these glands, the kidney stone should no longer be created.

Kidney stones and their relationship to chronic kidney disease

Someone who develops kidney stones may be more likely to develop chronic kidney disease or even renal failure if he or she does not treat the kidney stone. Renal stones that are left in the body for periods of time can affect the flow of urine through the kidneys. In certain types of kidney stones, the jagged edges may damage small vessels in the kidney as it passes causing scarring. It is important to seek treatment for kidney stones right away if you are showing symptoms.

A paper published out of the University of Chicago in February 2007 showed that “the prevalence of pre-end stage renal disease kidney stones among African American hemodialysis patients is significantly higher than the prevalence of kidney stones found in the general African American population.”

If you have kidney stones you may be at a higher risk for chronic kidney disease. Make sure to talk to your doctor about ways to prevent the kidney stones from coming back and how to keep your kidneys healthy.

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