August 17th, 2011
10:20 AM ET
Every weekday, a CNNHealth expert doctor answers a viewer question. On Wednesdays, it's Dr. Otis Brawley, chief medical officer at the American Cancer Society.
Question asked by Julie from Illinois
I had surgery eight months ago to remove stones from my bladder. Today I found what I believe was a stone stuck to my vagina wall. I also had to have a urine bag for seven days after the surgery. Could it have come from where they inserted the tube in my kidney? I have had surgery for kidney stones in the past. I believe I recently passed another stone. Is this possible? What should I do?
Stones of the urinary tract which are also called kidney stones, nephrolithiasis or urolithiasis are common. It is estimated that 10% of people living to age 70 will have them.
There are several types of kidney stones. They are most commonly made of calcium, oxalate, cysteine or uric acid. In all cases a crystal forms and grows over time. It can take several weeks for a large stone to develop.
Stones develop in the part of the kidney that collects urine. Small stones most often pass from the kidney through the ureters and on to the bladder and out with urine. They may not be noticed or the patient may have the sensation of urinating gravel.
A larger stone, on the order of 10 mm or a 1/3 of an inch, can cause pain as it passes down the ureter to the bladder.
The pain can be mild and treated with a mild pain medicine such as ibuprofen or a very noticeable ache that requires narcotics. Pain can sometimes come in waves with nausea and vomiting. This is known as renal colic.
A passing stone can cause bleeding, which leads to a pink-colored urine, or sometimes one can actually see blood in the urine.
A physician can image and measure stones in the urinary tract using X-ray, CT scans or ultrasounds. The treatment of a stone that is painful but small is hydration and pain medicine. Over time the stone will pass. Some patients can be treated as outpatients, but severe pain or pain with nausea may need to be treated in the hospital.
Some stones are so large that they cause pain but never pass. These stones need to be removed.
The most common treatment to remove a stone is lithotripsy. This involves high energy shock waves being directed at the stone. The stone frequently breaks up into smaller pieces and is passed in the urine. Stones that are resistant to lithotripsy may be treated with a surgical procedure known as a percutaneous nephrolithotomy, in which an instrument is passed through the skin into the kidney to grab and break up or remove the stone.
Others are treated with ureteroscopy, in which a scope is passed through the urethra and bladder and up the ureter into the kidney. Instruments are passed through the scope to break up the stone into small pieces that can be urinated out.
People who find a passed stone should save it and give to their health care provider.
Some doctors even encourage patients to strain urine to collect stones. Analysis of the stone can help in developing a plan to decrease the risk of future stones. Patients prone to certain stones are given special diets or medications to prevent them.
In general, drink lots of fluids to decrease the risk of stone formation. Some kidney specialists say that an adult should make at least two liters of urine per day.
About this blog
Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.