The Kidney Rocks - Stones of the Urinary Tract 

Contributed by,

Ramy M. Hanna MD and Huma Hasnain MD
UCLA – South Bay Nephrology

What are kidney stones?

Kidney stones, or nephrolithiasis, are one of the most common causes for urgent care, emergency room and primary care visits. Nephrolithiasis, the technical term, is Greek for kidney stones or kidney pebbles. Kidney stones are prevalent in approximately 10.1% of men and 7.1 % of women in the United States, the number of people affected by this condition seems to be rising. Kidney stones usually cause extreme pain and can lead to a severe infections and even kidney function decline, if left untreated. Kidney stones occur as a result of biochemical abnormalities in the blood and/or urine, this can be the result of genetic, dietary, and/or environmental factors. Evaluation by a nephrologist, a kidney specialist can help prevent recurring kidney stones.

What causes kidney stones?

Kidney stones are the result of an abnormal amount of electrolytes or chemicals in the urine. Since urine volume is not constant, the electrolytes in the urine are measured by their concentration.

The higher the urinary concentration of certain chemicals, the higher the likelihood of the formation of kidney stones. For example, any process that increases the concentration of calcium and other chemicals in urine to a critical point (called super saturation) makes it more likely that stones will form. Once a stone forms the chemicals continue to deposit on the initial deposited stone allowing the stone to grow. 

Factors that increase the risk of developing kidney stones include:

• Drinking too little water.
• Eating a diet that's high in protein, sodium and sugar (fructose) may increase your risk of forming a kidney stone. Fructose can be found in table sugar and high fructose corn syrup.
• Excessive exercise.
• Obesity: high body mass index (BMI) has been linked to increased stones formation.
• Family history: If someone in your family has kidney stones, you're more likely to develop stones.

How to recognize a kidney stone?

             The classical symptom of a kidney stone is pain in the side or flank that can radiate down to the groin. The pain is severe, cramping and constant. Kidney stones can result in a wide array of symptoms including blood in the urine (hematuria), flank pain, pain with urination, nausea, vomiting, fevers, and chills.

Some kidney stones are as small as a grain of sand, others are larger. In general, the larger the stone, the more noticeable are the symptoms. You start to experience symptoms when the stone moves from the kidney to the ureter, the tube that connects the kidney to the bladder.

More Symptoms include:

• Severe pain on either side of your lower back
• More vague pain or stomach ache that doesn't go away
• Persistent need to urinate
• Urinating either more often than usual or a small amount of urine.
• Urine that smells bad or looks cloudy

How common are kidney stones?

Each year, more than half a million people go to emergency rooms for kidney stone problems. It is estimated that one in ten people will have a kidney stone at some time in their lives.

What are the most common types of kidney stones?

There are four main types of stones:

• Calcium oxalate:The most common type of kidney stones. Oxalate is a naturally occurring substance found in some fruits and vegetables, as well as nuts and chocolate.
• Uric acid: Foods such as organ meats have high concentrations of natural purines. High purine intake leads to a higher production of monosodium urate, which may form stones in the kidneys.
• Struvite:These stones are less common and are caused by kidney infection and they can grow quickly and become large
• Cystine:These stones are rare and tend to run in families with hereditary disorders.

How are kidney stones diagnosed?

• Medical history and physical examination.
• Blood tests that may reveal too much calcium or uric acid in your blood as well as the overall general health.
• Imaging tests to know the exact size and shape of the kidney stones like CT scan or a "KUB x-ray'' (kidney-ureter-bladder x-ray). In some cases, Intravenous pyelogram (lVP), which is a special type of X- ray that is taken after injecting a dye, is required.
• Later, your doctor will want to find the cause of the stone. The stone will be analyzed after it comes out of your body.

Treatment:

Stones are treated based on several factors including the severity of pain, the location of the stone, and the presence of infection.  Most patients can be treated at home, while others require admission to the hospital.  Pain medications, anti-nausea medications, intravenous fluids, and sometimes antibiotics are required for treatment. The presence of an obstruction of the urinary tract is a major factor in deciding whether surgery or other procedures are needed. If a stone is deemed too large to pass on its own, is extremely painful, or is obstructing a surgical procedure or other procedural attempts to dislodge/break up the stone maybe indicated. These are usually performed by urologists who are the surgical specialists of the kidneys, ureters, and bladder. 

Most kidney stones won’t require an invasive procedure. You can pass a small stone by:

• Drinking water as much as 3 liters a day may help flushing your kidneys.
• Pain relievers for mild pain
• Medical therapy to relax muscles of the ureter and helping you pass the stone.

Stones that are too large or causing severe symptoms need more extensive therapy like:

• Using sound waves to break up the stones (ESWL)
• Using scopes to remove the stones
•  Surgery

What can I do to decrease the risk of kidney stones?

• Drinking enough fluid will help keep your urine less concentrated with waste products. Your urine should appear very light yellow to clear if you are well hydrated

Sugar and high-fructose corn syrup should be limited to small quantities

• Restricting foods rich in oxalates. These include, beets, okra, spinach, Swiss chard, sweet potatoes, nuts, tea, chocolate and soy products
•  Eat more fruits and vegetables, which make the urine less acid. When the urine is less acid, then stones may be less able to form 
• Reduce excess salt in your diet
• You want to try to get to a normal weight if you are overweight
• Based on blood and urine tests, your doctor will determine which types of dietary changes are needed in your particular case

Are there any long-term consequences of having a kidney stone?

lf you have had one stone, you are at increased risk of having another stone. Those who have developed one stone are at approximately 50% risk for developing another within 5 to 7 years.

♦ Kidney Stone Clinical Program

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Disclaimer: The UCLA Health System cannot guarantee the accuracy of such information. The information is provided without warranty or guarantee of any kind. Please speak to your Physician before making any changes.