Urine contains various dissolved waste materials. When there is too much waste in too little liquid, crystals begin to form. The crystals attract other elements and combine to form a solid that will increase in size if it is not excreted from the body through urine. These chemicals are usually excreted in the urine by the body's own chemical called the kidney. In most people, enough fluids or other chemicals are excreted in the urine to prevent a stone from forming. The stone-forming chemicals are calcium, oxalate, urate, cystine, xanthine, and phosphate.
Once formed, the stone may remain in the kidney or travel through the urinary tract to the ureter. Sometimes small stones pass out of the body in the urine without causing too much pain. But stones that don't move can cause urine to pool in the kidney, ureter, bladder, or urethra. This is what causes the pain.
Treatment for a kidney stone depends on how large the stone is, what it is made of, whether it causes pain, and whether it is blocking the urinary tract. To answer these questions and find the right treatment for you, your doctor may ask you to have a urinalysis, blood test, X-ray, and / or CT scan. Sometimes a CT scan uses contrast agents. If you've ever had a problem with contrast agent, tell your doctor before you have a CT scan.
If your test results show that your kidney stone is small, your doctor may prescribe you to take pain relievers and drink plenty of fluids to force the stone through your urinary tract. If your kidney stone is large or your urinary tract is blocked, you may need additional treatment.
One treatment option is shock wave lithotripsy. During this treatment, kidney stones are broken into small pieces by shock waves. After treatment, the small pieces of kidney stones are passed from your body through the urinary tract and with your urine. This treatment usually lasts 45 minutes to an hour and can be done under general anesthesia, which means that you will be asleep and pain-free.
Another treatment option is ureteroscopy. This treatment is also done under general anesthesia. The doctor uses a long tube-shaped tool to find the stone and extract it, or to find the stone and break it into small pieces. If the stone is small, your doctor may be able to remove it. If it is large, it may need to be broken into pieces. In this case, a laser will be used to break the stone into pieces that are small enough to pass through the urinary tract.
PCNL is a technique used to remove certain stones in the kidney or upper ureter (the tube that drains urine from the kidney to the bladder) that are too large for other forms of stone treatment such as shock wave lithotripsy or ureteroscopy.
This procedure has been performed on many patients over the past few years and is an accepted standard of care for patients with large, very solid, or other types of refractory kidney stones. As such, it has replaced open kidney stone surgery in vast majority of patients.