Kidney Stones: How They Work

Yesterday, I signed off my kidney stone post with a line that I would be talking about Extracorporeal Shock Wave Lithotripsy (lithotripsy for short) today. I hadn't really planned on it, I just thought that was a funny throw away line to end the post.

But after the comment from cb, I think it might be worth it. I am intimately aware of the process and I mistakenly think that everyone else is, too. I'm all about sharing knowledge so this can be my contribution to the field of medicine. I've been doing more medical type posts over on my other blog Alzheimer's Moments lately. Maybe I missed my calling and should've been a doctor.

But I digress. Here's what cb wrote:

"I thought the shock wave thing was supposed to be a cool way to break up the stones. Is it NOT cool?"

If you read no further, let me sum this whole story up in a short answer, "NO NO NO it is NOT cool AT ALL!"

So in today's post I'll talk about kidney stones in general and then tomorrow I'll detail the lithotripsy procedure:

The pain of passing a kidney stone isn't from the stone itself. Most people conjure up an image that it is this huge boulder that gets caught in your hoo hoo dilly on the way out. Nope, that's not it at all.

The kidney stone, as it works it's way out of the kidney, travels down the ureter. The ureter is the tube that connects the kidney to the bladder (which is not the same as the larger urethra that goes from the bladder to the outside world). Think of the ureter as a hollow strand of angel hair pasta. Now think of pushing something the size of a grain of rice down through such tube. Where's the pain? Well the only way that the stone can move through the ureter is with pressure from urine that is backed up behind it.

The stone itself isn't smooth like a grain of rice as you can see in the pic above. It's more like a hard Rice Krispie. It has formed over time to be a craggy, jaggy, miserable little piece of junk that doesn't slip or slide through anything. So it gets caught on the way down, fighting and scratching the whole way. (This scratching of the ureter is what's causing the blood in my pee.) So the larger the stone, the more jagged it is, and how it gets lodged (think of that grain of rice getting caught sideways) in the ureter determines how much pressure will be needed to force it through. And that's where the pain comes in. As the stone fights to stay where it is, your kidneys keep on working like nothing is wrong. They clean, clean, clean your blood, diligently doing their job of creating urine to travel down the ureter. But alas, there is no place for it to go. So it is this pressure of urine backing up against the kidney that causes the pain.

In the best of cases, the stone moves through with minimal effort. It fights but doesn't get stuck. And it passes. Some stones, the size of a grain of sand, can be passed and the person doesn't even know.

What causes kidney stones? There are several factors:
• Genetics. This is inherited. Yep, I can thank my mom for this one. I generally blame her for everything else so why not this? After all, I have the scientific community and physical evidence on my side this time!
• Dehydration. Drink, drink, drink water! The way that kidneys work is that they remove toxins from the blood and dissolve them into water which produces urine. Think of adding sugar to a glass of water. Then you keep adding sugar. Eventually, the water becomes saturated and the sugar will fall to the bottom of the glass no matter how much you swirl the spoon. If the kidney doesn't have enough water to dissolve the toxins, the "sugar at the bottom of the glass" are minerals that form a stone in the kidney.
• Calcium. Many kidney stones are made of calcium. For those patients, they go on a dairy restricted diet.
• Minerals. Some people have a hard time eliminating certain chemicals. After years of trial and error in my diet, I have determined that my body can't process phosphorus. So where does one ingest phosphorus? Diet soda. As I understand it, to get diet soda to have bubbles, a form of phosphorus is added to get the carbonation because aspartame doesn't behave chemically like corn syrup. Ah, better living through chemistry. Not.

Tomorrow: My worst kidney stone nightmares and two lithotripsies aka how to spend $20,000 and not have any fun.

Update:

I get a large number of hits from Google searches on "Kidney Stone", "Lithotripsy", and other related terms. In an effort to make this subject easier to navigate on this blog, I am adding the following list of posts to every kidney stone entry to make them cross reference accessible.

If you are reading this because you have, or think you have, a kidney stone, I know your pain. Unless you've had one, and I've had some mild incidences and some really bad ones, no one can even imagine the level of pain.

Make an immediate appointment with an urologist. I am not a doctor and these are my experiences only!

You could be experiencing a kidney stone, but it may also be a urinary tract infection, a tumor, or other medical condition. Don't take any chances with your health!

These posts involve my passing of two giant 6mm stones this summer...three days apart! Wrapped in these posts are stories that detail my lifelong battle with them.

In the interest of clarity, these links are in temporal order.

First Signs Of A Stone May 7, 2007
What I Know About Kidney Stones May 8, 2007
A Discussion Of Lithotripsy May 9, 2007
Peeing Blood, No Pain May 11, 2007
Pain Returns May 18, 2007
Pain Again In The Back May 26, 2007
Bloody Urine Is Back July 12, 2007
Passed Kidney Stone #1 July 26, 2007
Passed Kidney Stone #2 July 30, 2007

I wish you well.
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