Understanding Kidney Disease

Intro: This is Weekly Dose of Wellness brought to you by MemorialCare Health System. Here's Deborah Howell.

Deborah Howell (Host): And welcome to the show. I am Deborah Howell, and today we'll be talking about the health of our kidneys and we'll learn a bit about kidney disease. Our guest today is Dr. Gaytri Gandotra, a nephrologist at MemorialCare Orange Coast Medical Center. Welcome, Dr. Gandotra.

Gaytri Gandotra, MD: Hi, thank you.

Deborah Howell (Host): Chronic kidney disease affects more than 47 million people in the US. Dr. Gandotra, what are kidneys and what are their functions?

Gaytri Gandotra, MD: So, I'd start by explaining the basic anatomy and physiology of a kidney. So we've got two kidneys, they're bean-shaped organs. They're found below our rib cage on either side of our spine in our back. Each kidney is roughly the size of your fist and it weighs about a third of a pound and it filters almost 40 gallons of blood per day. So kidneys are essentially filters. And they create urine which contains excess water, waste, and electrolytes. So, blood flow to the kidneys are very important. They receive about 20% of the blood pumped by the heart every minute. So our heart contracts and relaxes, contracts and relaxes, blood travels from the heart through a main artery called the aorta and it delivers one single branch of blood to each kidney. So the blood supply to the kidney, in other words, the blood pressure to the kidney is very important. And the kidney then cleans the blood, it filters it, and it gets rid of the extra waste, and this is excreted as urine. So once the kidney makes urine, inside each kidney we have one million filters. Each functioning unit of the kidney is called a nephron. That's why I'm called a nephrologist. So I explain to patients it's very similar to neurons in the brain. So each functional unit is called a nephron. Once the urine forms it flows down the ureter into the bladder, where we store our urine until we void and use the restroom. So that is the basic anatomy of the kidney.

Deborah Howell (Host): So they're very important. Now how exactly does the kidney clean the blood and make urine?

Gaytri Gandotra, MD: So inside each nephron, there's two main parts. There's many special cells inside the nephron, it has two parts. One is the glomerulus, which is the basic filter, and after that is the tubule. So the glomerulus receives blood from the heart, and small molecules like water, sodium, potassium, magnesium, calcium, all of them pass through the filter, and large molecules such as albumin don't pass through this filter. So one of the signs of kidney disease is finding albumin or protein in the urine. So it's normal to find electrolytes in our urine, toxin which we call urea which I'll talk about later, that passes easily into the urine, but larger molecules such as protein or albumin don't pass into the urine. And then there's the tubules which reabsorbs water. And so that's the basic, the two functional parts of how a nephron makes urine.

Deborah Howell (Host): Got it. You're being very, very descriptive, I really like it. Explain what the term creatinine and GFR mean to everybody.

Gaytri Gandotra, MD: Okay, so the term GFR, there's two terms I want to make sure that my patients at least are familiar with. GFR stands for glomerular filtration rate, and this is the rate that your kidneys are cleaning your blood. The normal GFR in a young, healthy male is 120 ml per minute. 120 ml per minute. And in females it's 100. So as you age, or if you have chronic kidney disease, which we'll talk about, the GFR goes down. So if a normal GFR is 100 and as you get older, or if you have diabetes or hypertension, that filtration rate starts to go down, say 50, 40, 30. When you're down to 10, 15, you're kind of near dialysis. So that's when doctors will say, oh, your kidneys are functioning at 30% or 40%, that's what they're referring to. Now, the GFR is a number patients say, where do you get this from? It's generated, it comes up in your blood test, in your lab. When you go to the lab, you get a chemistry, and there you'll see the GFR, and it'll spit out sort of a number. That number is an estimate. So if it says your GFR is 45, that doesn't mean you're exactly at 45%. That's just an estimate. So you could be 55% or 35%, but overall the way the lab does it is based upon the fact that your age, your sex, your creatinine, which I'll talk about, it puts it into a formula and it spits out a number. And that number is your GFR. So it's an estimate, so you shouldn't sort of hold that number exact.

Deborah Howell (Host): Because it would be different in the morning, or after you ate a piece of cake, or right? I mean it varies.

Gaytri Gandotra, MD: Not necessarily after a meal, but it might vary based upon how hydrated you are. Yes. How hydrated you are, it will vary based upon your age or it'll vary based upon your creatinine. And creatinine comes from muscle mass, which I'll talk about. So the term creatinine comes from creatine, creatinine comes from creatine which comes from our muscle. So GFR is one thing that we look at in the blood test, and the second thing we look at is the creatinine. And the higher the creatinine, the worse your kidney function.

Deborah Howell (Host): Got it. Which brings us to chronic kidney disease.

Gaytri Gandotra, MD: Yes.

Deborah Howell (Host): Can you tell us what that is?

Gaytri Gandotra, MD: Yes, chronic kidney disease is also termed as CKD. And it's when you have kidney disease that is for longer than three months. So there's five things which can define, if you have five things for more than three months, you have chronic kidney disease: if you have a low GFR, if your filtration rate is less than 60, if you're anemic, if you have protein or blood in your urine, if you have changes on your kidney biopsy, or if you have changes on the kidney ultrasound. When you have kidney disease for a long period of time, the shadowing, when we do an ultrasound, the shadowing of our kidney is different. And so those are called changes on ultrasound. So if you have any of these for longer than three months, you have chronic kidney disease. So you can have a normal filtration rate, a normal creatinine, but have protein in your urine, and you still have chronic kidney disease.

Deborah Howell (Host): Understood. What are the common causes of kidney disease in the US?

Gaytri Gandotra, MD: The number one cause of chronic kidney disease in the US is diabetes. Diabetes affects the eyes, the nerves, and the kidneys. The number two cause is hypertension. And number three is advanced age.

Deborah Howell (Host): Okay, easy enough to understand. And what are the signs and symptoms of kidney disease?

Gaytri Gandotra, MD: So as your filtration rate goes down, the kidneys have a hard time getting rid of water, salt, potassium, acid, and waste products. So you might get swelling in your legs. You might get water accumulation in your lungs, so patients will say they get short of breath. Your urine output might go down. You might feel nauseous, have a poor appetite, feel fatigued, perhaps an inability to concentrate or frequent headaches. Those are common causes of advanced CKD. And kidneys regulate blood pressure. So as your kidney function goes down, you have a hard time regulating blood pressure, so you might have hypertension.

Deborah Howell (Host): Interesting how it all affects each other and so many functions in the body. When should a person see a nephrologist?

Gaytri Gandotra, MD: Typically, primary care doctors will send their patients to a nephrologist when their filtration rate is less than 30. That's the time when the kidneys have a hard time excreting potassium and acid and waste products. Other times you should see a nephrologist is if you're known to be anemic. If you have blood or protein in your urine. If there are abnormal findings on your CAT scan or kidney ultrasound. If you have a family history of kidney disease. If you have high blood pressure which is difficult to control with the medications that your primary doctor manages you with. Those are common reasons for patients to come to a nephrologist.

Deborah Howell (Host): Okay, now switching gears just a little bit, what is anemia, and tell me about the different types of anemia.

Gaytri Gandotra, MD: Anemia is a condition where you don't have enough red blood cells to carry oxygen from the lungs to the rest of the body. So the normal, the number we look at in the blood test is called hemoglobin. There's a different hemoglobin within a normal range for males and for females. Kidneys produce a hormone called erythropoietin. That hormone stimulates the red blood cells to mature. So if you don't have good kidney function, you don't produce that hormone, and your red blood cells don't mature, therefore you become anemic. So that's why we commonly see anemia in patients with CKD. And how we treat that is we give them iron pills or we give them this hormone, we inject actually the hormone in these patients once a week intravenously or subcutaneously.

Deborah Howell (Host): And what hormone is that?

Gaytri Gandotra, MD: It's called erythropoietin.

Deborah Howell (Host): Okay, got it. And what are the symptoms of being anemic again?

Gaytri Gandotra, MD: One can get short of breath, you can have difficulty exercising, depression is one. Patients can be prone to cold. They can have pale skin, muscle weakness, sometimes a tendency to bleed. They can be lethargic, impaired thinking, and if it's advanced you can have low blood pressure, rapid heart rate, chest pain. I mean if you have advanced, severe anemia, those are symptoms one can have.

Deborah Howell (Host): Okay, but there is that treatment with the pills and the erythropoietin injections.

Gaytri Gandotra, MD: Correct, and you should, you should catch it early. So you should be checking your blood tests frequent enough to know that you are mildly anemic and kind of intervene and figure out the cause of anemia. Kidney disease is only one cause of anemia. But if you are, say, having a bleed, say if you have a bleed from your rectum or colon, there's many other causes, so you have to have your doctor help you figure out why you're anemic.

Deborah Howell (Host): Exactly. I have a final question for you, doctor. What are some measures to help prevent kidney disease?

Gaytri Gandotra, MD: So I call it the eight golden rules. One is to make sure that you are checking your kidney function with your doctor. And to check your blood creatinine and get your kidney function checked regularly. Identify the risk factors for kidney disease. If you are an older patient, or if you have a family history of kidney disease, diabetes, hypertension, it's important to get your kidney function checked. Number two, to check your blood pressure regularly and keep a log. So if your blood pressure is too high or too low, that affects your kidney function. Eating clean, adopting a DASH diet, so a DASH diet is a diet which is rich in fruits and veggies, and beans and seeds and nuts, is good. Staying active, to incorporate exercise into your lifestyle. If you smoke, to quit smoking. Pain medications, oftentimes we take ibuprofen for pain, headaches, women take it during their menstrual cycle. So ibuprofen is bad for the kidneys, if you take too much of it. And any family of drugs that are cousins of ibuprofen on the market, naproxen, those are all, it comes into a class of drugs called NSAIDs. So I just tell patients ibuprofen is bad, you can take it once in a while, but if you already have kidney disease it's a big no-no. And most importantly, staying hydrated. Make sure you're drinking adequate amounts of water, which is very important. And I tell patients to let go of the energy drinks and the sports drinks and sodas, which are high in phosphorus. So good old water, plain water is good.

Deborah Howell (Host): Thank you so much, Dr. Gandotra, for being on the show today. We all learned a lot and we enjoyed having you very much.

Gaytri Gandotra, MD: Okay, thank you.

Deborah Howell (Host): To learn more or to hear a podcast of this show, go to memorialcare.org. That's memorialcare.org. That's all for this time. I am Deborah Howell, have yourself a terrific day, and hydrate!