About Stone disease
Kidney Stones (calculi) are hardened mineral deposits that form in the kidney. They originate as microscopic particles and develop into stones over time. The medical term for this condition is nephrolithiasis, or renal stone disease.
The kidney filters waste products from the blood and add them to the urine that the kidneys produce. When waste material in the urine do not dissolve completely, crystals and kidney stones are likely to form.
Small stones can cause some discomfort as they pass out of the body. Regardless of size, stones may pass out of the kidney, become lodged in the tube that carries urine from the kidney to the bladder (ureter), and cause severe pain that begins in the lower back and radiates to the side of the groin. A lodged stone can block the flow of urine, causing pressure to build in the affected ureter and kidney. Increased pressure results in stretching and spasm, which cause severe pain.
Kidney stones form when there is a high level of calcium (hypercalciura), oxalate (hyperoxaluria), or uric acid (hyperuricosuria) in the urine; a lack of citrate in the urine; or insufficient water in the kidneys to dissolve waste products. The kidneys must maintain an adequate amount of water in the body to remove waste products. If dehydration occurs, high levels of substances that do not dissolve completely (e.g.,calcium, oxalate, uric acid) may form crystals that slowly build up into kidney stones.
Urine normally contains chemicals - citrate, magnesium, pyrophosphate - that prevent the formation of crystals. Low levels of these inhibitors can contribute to the formation of kidney stones. Of these, citrate is thought to be the most important.
Treatment Options, Medical Treatment
Treatment depends on the size and type of stone, the underlying cause, the presence of urinary infection, and whether the condition recurs. Stones 4mm and smaller (less than ¼ inch in diameter) generally pass without intervention in 90% of cases; those 5-7mm do so in 50% of cases; and those larger than 7mm rarely pass without intervention. Patients are advised to avoid becoming sedentary, because physical activity, especially walking, can help move a stone.
If possible, the kidney stone is allowed to pass naturally and is collected for analysis. The patient is instructed to strain their urine to obtain the stone(s) for analysis. It is important to analyze the chemical composition of kidney stones to determine how to prevent recurring stone formation. Each voiding should be strained until the physician instructs the patient otherwise.
Dietary changes may be required and fluid intake should be increased. Patients with stones must increase their urinary output. Generally, 2000cc of urine per day (slightly more than 1/2 gallon) is recommended and patients should drink enough water to produce this amount of urine daily. In some cases (e.g., some cystine stone formers), even higher levels of fluid intake are required.
Other dietary changes, as well as medication or prescription drugs may be recommended by your physician. These generally include thiazides (water pills) to increase urinary volume, as well as pain relievers to treat pain caused by kidney stones.
ESWL ( Extracorporeal Shockwave Lithotripsy)
Extracorporeal Shock Wave Lithotripsy (often called "ESWL" for short) is a method of fragmenting kidney stones without surgery. High pressure shock waves produced outside the body are focused on the stone. This reduces the stone to smaller particles, which are subsequently passed out in the urine. For large stones, a Double J Stent (a temporary ureteric tube) is at times placed by a cystoscope through the normal urinary passage. One end of the stent lies in the kidney while the other in the bladder with nothing visible from outside. This dilates the ureter and prevents obstruction during the passage of stone particles. When the patient is stone free, the stent is removed with the help of cystoscope without any operation.
Treatment Options, Surgical Treatment
If a kidney stone does not pass on its own, surgery is considered. Urologists use several procedures to break up, remove, or bypass kidney stones.
Ureteroscopy
Ureteroscopy is an examination of the upper urinary tract, performed with an endoscope that is passed through the urethra, bladder, and then directly into the ureter. The procedure is useful in the diagnosis and treatment of kidney stones.
The procedure may be performed with either a flexible or rigid fiberoptic device while the patient is under a general anesthtetic. In a ureteroscopy procedure the urologist removes the stone using a retrieval device. Smaller stones can be removed all in one piece, while larger stones may need to be fragmented prior to removal.
Ureteroscopy uses the body's natural orifice, and therefore is an outpatient procedure. Most patients are able to go home the same day of the procedure. In some cases an overnight stay is required, but generally not longer than 24 to 48 hours.
PCNL (Percutaneous Nephrolithotomy)
For Kidney stones larger than 2cm in size, or harder composition stones, a more invasive but extremely effective therapy called percutaneous nephrostolithotomy.
PCNL is performed under general anesthesia. This procedure involves direct fragmentation of the kidney stone through a small incision made in the flank through which a telescope (called a nephroscope) is passed directly into the kidney. Ultrasonic, electrohydraulic, or laser fragmentation of the stone can then be performed through the nephroscope under direct vision.
A plastic tube (called a nephrostomy tube) is temporarily left in the kidney, exiting the flank in order to optimize drainage of the urine from the kidney following PCNL.
Open Surgery
Open surgery is the most invasive form of treatment for urolithiasis. It is performed infrequently and performed primarily to remove very large and complex staghorn calculi, or extremely hard stones. Other indications for open surgery are extreme obesity, an anatomically abnormal kidney, or an infected and nonfunctioning kidney requiring complete removal. Please discuss the different options with your physician.
