Morgan Elizabeth Endress, PA

Kidney stones can be smooth or jagged and are yellow to brown in color. They are mostly comprised of the minerals calcium, oxalate, and phosphorus. Examining the stones to see what they are made of can show what caused the stone to be formed in the first place. For example, a stone made of mostly calcium, which is the most common type, can happen any time the urine becomes too concentrated due to dehydration or a blockage in the kidney. A uric acid stone forms when acid levels in the urine get too high, usually due to excessive consumption of animal protein such as meat and fish. A struvite stone is a sign of certain infections, and a cystine stone can be due to a genetic disorder that raises the risk of kidney stones.

The most common symptom of kidney stones is pain, either in the back or lower abdomen, or severe pain when urinating. There may also be blood in the urine. Treatment for kidney stones depends on how large the stone is. Very small stones can pass out of the body on their own, and they do not require treatment other than drinking adequate water and taking pain killers. Larger stones need to be broken apart and removed. The main treatment options are:

• Shock wave lithotripsy, which uses sound wave vibrations to break apart the stone
• Percutaneous nephrolithotomy, or the use of a very tiny tool (like a wire inserted through the back) to break apart and remove the stone
• Ureteroscopy, a thin tube inserted through the urethra and bladder to the stone, where tiny tools can grasp the stone and remove

People who have had one kidney stone are at risk of developing another. To reduce this risk, patients are given instructions specific to the type of stone they developed. Generally the instructions will include drinking more water to dilute the urine, but it may also involve lowering sodium intake or eating less meat.

• The bladder, which stores urine.
• The urinary sphincters, which are muscles around the opening of the bladder that hold urine in.
• The urethra, which is the tube where urine flows out of the body.

Urodynamics tests are normally performed together as one series, but depending on patients' symptoms, only one or some of them may be necessary. The most common tests are:

• Cystometrogram, which measures the amount of urine the bladder can store and how full it is before someone has the urge to urinate. Doctors may order this test if she suspects their patient has a weak bladder.
• Pressure flow study, which measures the pressure in the bladder while urinating. This test helps locate a blockage in the bladder.
• Uroflowmetry, which measures how much and how fast urine flows out of the body. This test is usually recommended when patients have difficulty urinating or they have a slow stream.
• Urethral sphincter electromyography, which measures how strong the muscles and nerves in the bladder and sphincters are. Doctors may request this test if the problem they are experiencing is linked to muscle or nerve damage in the lower urinary tract.
• Urethral pressure profile, which measures the pressure along the urethra while the bladder is gradually filled with fluid. Low pressure could mean someone has a weak urethra, a contributing factor to urinary incontinence (loss of bladder control).

For a few hours following a urodynamics study, patients will likely feel some soreness or discomfort. It is recommended to drink at least one glass of water every half hour for two hours to relieve these symptoms. Holding a warm, moistened washcloth over the area where discomfort is felt or taking a warm bath may also help. Results for cystrometrograms and uroflowmetry are typically available immediately after the test, but results for the other tests may take a few days. When doctors have reviewed a patient's test results, he or she will discuss them with the patient, along with any treatments the patient may need.