The First Signs: Recognizing the Symptoms of Kidney Stones

Cheryl Martin (Host): It's often described as one of the most painful experiences a person can endure, kidney stones. While they are a common medical issue, there are lots of misconceptions about what causes them and how to prevent them. Dr. Kelly Caldwell is here to shed some light on the subject. She's a urologist with Memorial Hermann Medical Group. We'll discuss everything from the symptoms you should never ignore, to the simple lifestyle changes that can make a big difference.

Stay with us as we get the inside scoop on how to stay hydrated, healthy and kidney stone free. Welcome to Everyday Well™, a health and wellness podcast brought to you by Memorial Hermann Health System.

I'm Cheryl Martin. Always tune in for the latest tips and information about healthcare topics that matter most to you. And one of them is probably our topic today, kidney stones. Dr. Caldwell, thanks for coming on.

Kelly Caldwell, MD: Hi. Thank you guys for having me. I'm excited to be here to talk about kidney stones today.

Host: So let's start with a quote that really grabs people's attention. Even women who have had multiple children tell me that the pain of a kidney stone is worse than childbirth. Have you heard that? And if so, tell us why kidney stones are so excruciatingly painful and what's happening inside the body that causes this level of pain.

Dr. Kelly Caldwell: I have actually heard that from several patients that stones are worse than childbirth. And stones can be either completely asymptomatic or can be excruciatingly painful. Kidney stones are formed in the kidney, and when they're sitting in the kidney, patients usually have no idea they have them.

They're just sitting in the kidney not causing any pain or discomfort. It's when the kidney stones decide to move that they become a problem. The urine has to travel from the kidneys all the way down to the bladder through a small tube called the ureter. When this happens, when the stone decides to move, the stone can drop into the ureter and get stuck, and you're essentially left with a plumbing problem.

The kidney continues to produce urine. And the kidney starts to swell up because of the backflow of urine being trapped in the kidney. It's this swelling of the kidney and this dilation within the inside of the kidney that causes the horrible pain that you've heard about. And until that stone passes or until it's removed, it can cause intermittent pain along with the classic associated symptom, which is nausea.

Host: So what are some of the major risk factors for developing kidney stones?

Dr. Kelly Caldwell: Diet plays a big role in the production of stones. One of the biggest offenders of kidney stone formation is just not being hydrated enough. We want our patients to be making at least two to two and a half liters of urine a day when they are at risk for stone formation. That usually means you should be drinking at least two and a half liters of fluid a day in order to keep up with that.

There are some certain medical conditions that play a particular role in making stones. Obesity actually is a big risk factor for creation of stones. There are certain GI conditions that can also increase your risk of stones like Crohn's disease or patients that have already had some type of bariatric surgery like gastric bypass.

There's a problem in the way that the nutrients are absorbed within the gut and it increases your risk for making stones. There's also certain genetic conditions that can predispose you to make stones because you have abnormalities in certain transporters on the kidneys, and there's hormone problems that can cause issues with calcium regulation within the body.

So there's multiple reasons why patients can be at risk for developing stones.

Host: You mentioned dehydration, so let's talk more about that. And also what about the role of high sodium, a high sodium diet may play in kidney stone formation, and then what are some practical, easy steps people can take to modify their daily habits?

Dr. Kelly Caldwell: So there are multiple types of stones that the kidneys can make. Most people who develop a kidney stone are going to make a calcium oxalate stone and calcium oxalate stones are formed in patients who are dehydrated and one of the biggest offenders is high sodium as well.

When the urine is very concentrated, a lot of those things that are excreted by the kidneys have a higher chance of concentrating and crystallizing within the urine and forming stones. Sodium, when we take that in, in our diet, whether that's a big thing of fries that we got when we were eating fast food or a big bag of chips, the body has to get rid of that excess sodium.

When the body gets rid of it, it pulls sodium into the urine using a specific transporter on the kidney. That transporter not only will move sodium into the urine, it will pull calcium into the urine. And when you increase the amount of calcium in the urine unnecessarily, you can increase your risk of forming a calcium oxalate stone.

Host: When you say high amount of sodium, how much are you talking about or what should we be aiming for in terms of the maximum amount of sodium a day?

Dr. Kelly Caldwell: Typically, we encourage our patients to do a heart healthy diet, and so we encourage our patients to try and limit your sodium intake to 2,500 milligrams per day. And sometimes that can be really hard to track because when we're eating out, we have no idea how much sodium is in the food that we're eating.

But it's really important to keep an eye on your labels because sodium can really creep up on you in a lot of processed foods.

Host: So for someone who thinks that they might be experiencing a kidney stone, what are some of the key symptoms they should look out for?

Dr. Kelly Caldwell: So the classic symptoms are going to be flank pain. Flank pain is a pain that happens on the side up under your ribcage and near your back. And that pain can radiate around the front of your abdomen, down into the groin. So that's the typical pain that you'll see. Some patients will also develop blood in the urine.

Most patients when they're trying to pass the stone will also have a lot of nausea, vomiting, and so they won't be able to keep any food or any water down.

Host: So how long can you have a stone and not realize it before you start having even these symptoms.

Dr. Kelly Caldwell: So some patients won't have any symptoms at all. Remember? You know, if the stones are up in the kidney, some patients can have those stones sitting in the kidney for years and they'll have no idea. If that stone is not causing any problems like pain or blood in the urine or even urinary tract infections, you wouldn't be looking for those stones because you're not trying to find an explanation for a problem per se.

Some patients will have some of these symptoms, which are mild, and they go and get these symptoms evaluated and we find them on imaging.

Host: So when someone arrives at the emergency room in pain, what's the initial medical approach for the patient with a kidney stone?

Dr. Kelly Caldwell: The first thing we typically do is just try to get the patient comfortable. These patients usually are in 10 out of 10 pain and vomiting, and so we usually administer some pain medication and some nausea medicine to get their pain under control. And then we do some testing. We always check the urine for any evidence of blood or infection.

We would typically do a panel of blood work that includes kidney function and electrolytes. And then the classic test that we try to order when we suspect a kidney stone is a CT scan. It's the most sensitive scan that will diagnose stones anywhere in the urinary tract, including the kidney and ureters.

Ultrasounds and x-rays can be used. They're not as sensitive as CT scans. Ultrasounds are really only looking at the kidneys and the bladder, and so you'll miss some small stones within the ureter, but kidneys x-rays and kidney ultrasounds can be used, but sometimes we'll miss the diagnosis in some patients.

Host: So what factors determine whether a patient can go home to pass the stone on their own or if they will need further intervention?

Dr. Kelly Caldwell: So the first thing we want to make sure is that the patient is stable, is the patient's kidney function okay? Do they have concern for infection? And how is their pain? Those are the things that we're evaluating in the emergency room. For patients that have horrible pain, that's not getting controlled with IV pain medicine, those patients may need to come into the hospital for further intervention.

If a patient has a significant compromise of their renal function, we also may need to intervene more urgently. One of the other things that can be very serious is if you have an infection in the kidney and a stone. That requires emergent intervention. If a patient is doing okay in the emergency room and they don't have any of these concerns, we can send them home with some pain medication, some tamsulosin which is a common medication, used to relax the ureter to see if we can get the stone to pass, and these patients can follow up with a urologist outpatient to see if they can pass the stone on their own.

Host: So there are certain people who have been advised to take calcium supplements. What's the best way to do so to prevent them from forming kidney stones?

Dr. Kelly Caldwell: So this is a common misconception. I have seen multiple patients who have been advised, by either their OBGYNs or their primary care doctors that they're not supposed to take calcium supplements for their bone health because they have made a kidney stone in the past. This is actually not true. We want our patients to have good, healthy bone health, because osteoporosis and fractures are really serious.

And so we want our patients who need calcium supplementation to take them, we encourage patients to take a normal dietary calcium intake for their gender and their age, but we just want patients to take those supplements with food. If you're taking calcium supplements without food, you will absorb a lot more of that calcium and you may kind of overload the system and increase urinary calcium in that way. If you take the calcium with food, some of that calcium will be absorbed, which is what you need, but some of that calcium will bind to other things in your food and within the gut that will actually get discarded as waste and it'll actually prevent your risk of making kidney stones.

Host: So for those who've already had one kidney stone, what kind of follow-up evaluation or testing would you recommend to prevent future stones?

Dr. Kelly Caldwell: So most patients who have just had one stone and their CT's shown no evidence of additional stones that may be coming down the pipe at a later time; I offer pretty conservative follow up. They can check in, you know, periodically with ultrasounds of the kidneys. I offer patients a yearly x-ray if they just want to get their kidneys checked out to see if they have any evidence of stones.

But we don't have to be as aggressive with those patients, unless they are really interested in how they can change their diet to prevent stones. The recommendations are that if we have a patient who has risk factors for making stones or has a medical condition we know is associated with stones, or a patient who has demonstrated recurrent stone formation in the past, we recommend additional testing to really look at what your stone is made of. So we analyze the stones that you've passed in the past and we also test the urine using a 24 hour urine. And we're looking at different components of the urine that we can modify, either with dietary recommendations, but even sometimes with medications so that we can decrease your risk of making stones in the future. So once I do my initial evaluation and I have a patient stable either on medications or a diet, or if they don't have very many stones, I usually see my patients back once a year to do an x-ray and check in to make sure everything is going okay.

Host: Anything else you'd like to add about the diet? You mentioned changing the diet because I'm assuming that this would also help a person who has never encountered kidney stones. You mentioned a heart healthy diet and a decrease in sodium. Anything else? What kind of diet would aid one in having stones or getting them the second time?

Dr. Kelly Caldwell: Yeah, so the things that we encourage the most, number one, hydration. That is key. Trying to get at least two and a half liters of fluid a day is really important. We talked about sodium restriction. The other part of your diet that can be modified is oxalate. Oxalate is in a lot of foods like leafy green vegetables like spinach, it's in nuts and it's in dark chocolate and oxalate, when we take that in our diet can be excreted by the kidneys and that will increase your risk of kidney stone formation in the future. And so I always give a list of foods that are really high in oxalate to my patients. Tell them to take a look at that list and try and limit those things from your diet if you can.

Most of the time when I test the oxalate in patient's urine, it's in a pretty normal range, but for some patients who are having a spinach salad every single day, or who eat a half a can of nuts every day, changing your intake of oxalate can make a huge difference on your stone formation. So, we also encourage patients to get a normal amount of calcium in the diet because again, normal calcium actually helps bind harmful things that are in our food that can actually increase your risk of stones. So you want normal calcium within your diet. A couple other things we recommend would be limitation of animal protein. So animal protein is any animal with eyes. We're talking chicken, fish, beef, all those things. And we usually recommend about eight ounces of that per day.

Host: You know what? I'm really glad that you are educating us on oxalate because on one hand you hear all the time eat a lot of green vegetables so spinach or kale and all these things that that's what you should have in your diet. But you are saying to limit that.

Dr. Kelly Caldwell: Exactly, and so eating a healthy diet may be different for someone who makes stones, right? So we do want patients to eat vegetables. Obviously. We want patients to be healthy. We want them to turn to things like spinach and kale before they turn to a bag of chips. But for a stone former, that may put them at increased risk of making stones.

And so, for some of my patients, I say, well have a salad that's half spinach, put some romaine lettuce in it. And so you really just have to know what kind of stones you're making and if that's a problem for you, and that's where the evaluation with your doctor comes into play. What kind of stones are you making and what kind of stones are you trying to prevent?

And that way you can kind of tailor your dietary recommendations for that patient specifically.

Host: And in closing, if you got kidney stones one time, does that automatically mean you'll get them again? Or that you're prone to?

Dr. Kelly Caldwell: It is not a slam dunk that you'll get them again. But the biggest risk factor for the development of stones is a personal history of stones. And so once you've made one, you're at significantly higher risk for making another one in the future.

Host: Okay. Dr. Kelly Caldwell, you've done such a great job educating us on kidney stones and also recognizing the symptoms. Thank you so much.

Dr. Kelly Caldwell: Thank you for having me.

Host: Here at Memorial Hermann, a urologist will help you navigate this common condition so you can get back to a life free from kidney stone pain. Find a urologist and schedule your appointment online when you visit memorialhermann.org/kidneystones. If you found this podcast helpful, please share it on your social media and check out our podcast library for other topics of interest to you.

Thanks for listening to Everyday Well™ brought to you by Memorial Hermann Health System.