Carl Maronich (Host): This is Meaningful Medicine, a Novant Health podcast bringing you access to leading doctors who answer questions they wish you would ask. I'm your host, Carl Maronich. And with me today is Dr. Michael Perttunen, a urologist with Novant Health. And we're going to be talking about kidney stones, what they are, how they develop, how they're treated and maybe, most importantly, how to prevent them. Doctor, welcome to the podcast.

Michael Perttunen, MD: Hey, Carl. Thanks for having me. It's a pleasure to be here.

Host: Yeah. Well, we're glad to have you. And let's start maybe with the basics and talk about just what a kidney stone is and what causes them in the first place.

Michael Perttunen, MD: Yes, sir. So, kidney stones or nephrolithiasis, as we like to call it, to make it sound more complicated, they're just small, hard mineral deposits that you find in your kidneys. They typically happen when your urine becomes what we call supersaturated with certain substances, and then you can have crystal growth in your urine leading to kidney stones. The most common type is calcium oxalate. That's up to about 80% of the stones, and there's a few other types, but that's kind of the heavy hitter.

Host: Often you hear that hydration is an effective way to prevent kidney stones. How much water should somebody realistically be trying to drink in a day?

Michael Perttunen, MD: So, it's not so much about how much you're trying to drink, it's about how much you need to pee, right? So if you're out and working in the hot sun, you're going to have to drink more to stay hydrated. Our goal is to about two and a half liters of urine a day. That's a lot of pee. I don't make that much pee in a day, but I always tell my patients to. So usually, you have to drink about 84 to 100 ounces of fluid at least per day.

Host: Do all fluids count or is really water the main thing that you want to be taking in?

Michael Perttunen, MD: Water is best, especially if you can incorporate a little bit of lemon or lime juice in the water, particularly lemon juice. I prefer any fluid over no fluid, but water's preferred. Things like tea and dark sodas can always contribute to stones, but it's better than nothing.

Host: Are there certain types of food, or you just mentioned some beverages that can increase the risk of kidney stones and, you know, what should most people kind of be wary of in that regard?

Michael Perttunen, MD: Yeah. So, there definitely are some foods and drinks that can contribute to stone formation. Particularly if you look up online what a stone diet is, it's all about limiting your oxalate intake, which is a stone compound. You'll find these things in things that you may think are particularly healthy like spinach, rhubarb, nuts. So, I actually tend to try to stay away from the stone diet because of that, because you're going to be left scratching your head not knowing what you can eat. So in general, I tell people to, you know, a heart-healthy diet, lots of fresh fruits and vegetables. That's kind of the basic tips I tell people.

Host: High protein seems to be the healthy way to go, but is there a link between some protein intake and kidney stone risk?

Michael Perttunen, MD: Correct. Yeah. So, animal-based protein is worse than plant-based protein. So, we generally tell people try to limit their animal intake, their animal protein intake, so beef, pork, chicken, fish, and try to incorporate a more plant-based diet.

Host: Does hereditary or genetics play a role in the development of kidney stones? And if someone has a family history, what should they be looking to do or not to do?

Michael Perttunen, MD: So, genetics can increase the risk of stones, but it is not going to guarantee you get stones. And so they've done actually some studies on twins, and they found that about the heritability of kidney stones is about 45% to 60%. But the main thing is diet, hydration, and then other rare metabolic conditions that you may inherit. But those are pretty rare, few and far between

Host: Does age—you know, can young people develop kidney stones, or is it something that mostly happens as we get older?

Michael Perttunen, MD: Oh, yes. It can definitely happen in younger individuals, and it's actually happening in the youth at an increasing rate. So, I'm more commonly seeing like 19, 18, 20-year-olds with kidney stones for the first time. But usually, it does increase with age.

Host: What are they attributing that to? Or have they figured that out yet?

Michael Perttunen, MD: Diet, diet and hydration status. So, you know, Mountain Dew in particular is not great for, kidney stones, and people just don't stay as hydrated as they used to.

Host: How should someone know when to seek medical treatment if they're suspected they may have a kidney stone versus just trying to pass the stone at home and give it time?

Michael Perttunen, MD: So if you're a first time stone former, if you have a kidney stone, you're most likely going to seek care in the emergency room just due to degree of pain, right? But if you know what stones feel like and you've passed them before, kind of the warning signs that may indicate you need something done urgently, the main one's fever. So if you have a fever greater than 100.4 degrees Fahrenheit, you need to be evaluated emergently. Otherwise, you can get pretty sick and septic from it. Otherwise, if you can't tolerate the pain, you need to go to the emergency room. Or if you can't eat or drink anything, because of the pain, you need to go to the emergency room, right?

There are a few other rare cases, like if you have stones on both sides blocking both kidneys, that's an emergency. Or for one reason, you only have one kidney and that kidney's blocked with a stone, that's also an emergency.

Host: Let's talk a little about treatment. What are the various treatment options and how do you as a doctor decide which approach you're going to use for which patient?

Michael Perttunen, MD: Good question, right? So, there are a few different treatment options here. The mainstay that we always prefer is called medical expulsive therapy. Essentially, that means we allow you to try to pass the stone, right? So, you drink plenty of fluids, pain control, and then we give you a medication called Flomax that helps you pass the stone. That can take four to six weeks to actually occur. So, I mean, your pain has to be controlled for those four to six weeks to undergo a trial of passage. Additionally, you know, that needs to be a ureteral stone. So, not sitting up in the kidney, not causing issues, but blocking the tube, draining your kidney. And in general, it needs to be less than 10 millimeters in diameter to consider to be passable. Anything bigger than that, you're looking at some sort of intervention.

So when it comes to interventions, we do have a few different options. One is called extracorporeal shock wave lithotripsy. That's where we essentially blast the stone from the outside with a high-powered ultrasound. So, there's no cuts in your body, no cameras in anywhere. It's outpatient surgery. You go home the same day. Recovery's pretty good. The one caveat to that is it needs to be visible on X-ray, because not all stones are visible on X-ray, and then also needs to be in the right size and location. If you start getting too big, like greater than 1.5, 2 centimeter stones, not a great option for shockwave.

The main workhorse for stone disease is called ureteroscopy. So, that involves a small telescopic camera that goes up your pee channel, and then we go and find the stone. If it's small enough, we just remove it with a basket. If it's big, we need to use a laser, break it up into smaller fragments, get those fragments out.

And the most invasive option we have is called the PCNL, which is a percutaneous nephrolithotomy. We typically use this for large stones in the kidney, so greater than 1 centimeter, if not 2 centimeters. And this involves putting a larger camera through the back directly into the kidney, through the meat of the kidney, and using essentially a jackhammer to break up the stones that way. It is very effective. It is quick at, you know, dissolving or getting rid of large stones, but it is more invasive. You're in the hospital for one night usually. You do have a tube coming out of your back for a day or so. So, we kinda reserve that for larger, more problematic stones. If you're going to have something done, typically it's either you're passing the stone, you're getting a shock from the outside, or I'm going up with a camera and a laser to get it out.

Host: For someone who has had a kidney stone, what long-term strategies do you recommend to prevent future stones?

Michael Perttunen, MD: So again, the biggest thing is hydration, aiming for about two and a half liters of urine a day. That can help limit stone formation in the future. Also, having a low sodium diet. So, less than 2 grams of sodium a day is what we recommend to help prevent stones. That's also what the, I think, American Heart Association recommends for a heart-healthy diet.

There used to be a thought that you need to limit your calcium intake. That's actually not true. We recommend normal calcium intake of about a gram. Then you have to limit, you need to try to limit your oxalate-rich foods, which is what I was talking about before with the stone diet. But I usually just tell people a heart-healthy diet with lots of fresh fruits and vegetables.

And then, limiting your non-dairy protein, so animal-based proteins There's also something we can do called a 24-hour urine study where you pee into a jug for a full day, breaks down all the metabolites in your urine, the volume of your urine. You do a little bit of blood work with it, and it kind of tells us exactly why you're forming stones. And so, we can generally help tailor a diet or medications to help prevent stones. Probably about 95% of the time what we end up telling people is you're not drinking enough and you need to incorporate some citrus fruit into your diet.

Host: Now, the test you mentioned, that's really for folks who have had a stone and what they might do with it going forward. Somebody who's never had a stone wouldn't go through something like that.

Michael Perttunen, MD: Correct. No, This is really for the repeat stone formers. And so, the way I was trained, the way I do it, I give everybody a freebie. You get one free stone before we start talking about doing an expensive workup. After that first stone, if it keeps recurring, then we'll consider doing some more, you know, non-invasive testing, but it is a handful for patients to pee into a jug for a full day.

Host: Earlier, Doctor, you mentioned you're seeing younger patients, an increasing number of younger patients. Is that also true all the population? You're just seeing more patients with stones these days?

Michael Perttunen, MD: The prevalence is definitely increasing. I think a lot of it has to do with climate. You know, the more dehydrated you are, the higher risk of stones you have, right? And so, especially here in the South, we actually live in the Stone Belt, is what we call it. It aligns with roughly the Bible Belt in America, just because it's the South and it's hot. But yeah, you see a lot of stones in the South where heat is a major factor.

Host: Well, doctor, before we let you go, what final words of advice would you give folks when it comes to kidney stones? And I think I know what they're going to be, but I'll let you deliver it.

Michael Perttunen, MD: Drink more water and try to incorporate some citrus fruit.

Host: Dr. Perttunen, thanks so much for being with us and sharing your expertise today.

Michael Perttunen, MD: No problem. It was my pleasure. Happy to be here anytime. If you have any four more questions, feel free to reach out to me and I'm happy to reach out.

Host: And to find a physician, visit novanthealth.org. And for more health and wellness information from our experts, visit healthyheadlines.org. If you enjoyed this podcast, please share it on your social channels and check out the entire Meaningful Medicine library for topics that may matter to you. And this is Meaningful Medicine. Thanks for listening.