April 18, 2021

Chronic Kidney Disease

Chronic Kidney Disease
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What do you need to know as a nursing student about Chronic Kidney Disease?

Today I'm going to be talking about chronic kidney disease. 
When a patient has a problem with their kidneys, it can either be an acute problem or a chronic problem. So it could be acute kidney injury which can often be reversed and fixed or it could be chronic kidney disease and that is not reversible. With chronic kidney disease they will eventually need dialysis or a kidney transplant. Chronic kidney disease is an irreversible loss of kidney function that happens slowly over time. It's often called a “silent disease” because it usually presents with no symptoms at first. We can say that a person has chronic kidney disease once their glomerular filtration rate or GFR is less than 60 ml per minute.


Chronic Kidney Disease

Hey there! Welcome back to nursing school week by week. I'm your host Melanie, and today I'm going to be talking about chronic kidney disease. So when a patient has a problem with their kidneys, it can either be an acute problem or a chronic problem. So it could be acute kidney injury which can often be reversed and fixed or it could be chronic kidney disease and that is not reversible. With chronic kidney disease they will eventually need dialysis or a kidney transplant. So chronic kidney disease is an irreversible loss of kidney function that happens slowly over time. It's often called a “silent disease” because it usually presents with no symptoms at first. We can say that a person has chronic kidney disease once their glomerular filtration rate or GFR is less than 60 ml per minute, and I'll talk more about the GFR here in a little bit but your GFR should be over 90 ml per minute normally.

So where are the kidneys in the body? We have two kidneys and they can be found underneath the rib cage, one on each side of the spine. The kidneys are really important. They do a lot of things for us. They regulate our acid-base balance, they get rid of waste products, they regulate fluid and electrolyte balance, and they regulate blood pressure with that whole renin-angiotensin-aldosterone system. The kidneys also secrete something called erythropoietin that's a hormone that lets the bone marrow know that it needs to start making more red blood cells. And the kidneys also make vitamin D which helps in the absorption of calcium.

There's a big push in the medical field right now to reduce the cases of chronic kidney, partly because it costs so much to treat. You know, money talks especially with big companies like hospitals, and about 25% of the Medicare budget is taken up by paying for people to get their dialysis treatment and kidney transplants. Kidney transplants are not cheap obviously.

So with chronic kidney disease we're going to see a decreased ability of the kidneys to filter waste products from the blood. What are some signs and symptoms of chronic kidney disease? The kidneys failing effects every body system. Some early signs and symptoms that we're going to see are: fatigue; the patients can be tired. We can see protein in the urine. Normally protein and blood cells would be too large to be filtered out through the kidneys but when they kidneys aren't filtering correctly, the albumin and the red blood cells can end up in the urine. We may see neuropathy or bone disorders, and definitely hypertension. There are a couple of reasons why we see hypertension in the chronic kidney disease patient and it’s that the GFR or the glomerular filtration rate is low so the glomerulus isn’t filtering much water at all. This makes the kidneys release renin. Remember the whole renin-angiotensin-aldosterone system? The kidneys think that the blood pressure is low since the glomerulus isn't filtering much water so they release renin to increase the blood pressure. But this is bad, because the patient already has hypertension just due to the increased fluid volume they’ve got going on due to their low GFR. So it’s this vicious cycle that we have to try to stop.

Some late signs and symptoms of chronic kidney disease are: metabolic acidosis. So that's a pH below 7.35 and this is because of all the waste products that are accumulating in the blood. So we may see the patient doing kussmaul respirations, those rapid deep breaths. Also, in the late stage of chronic kidney disease we're going to see a lot of Edema, since we're losing the albumin protein that regulates oncotic pressure. This means the fluids are going to leak out into the tissue causing swelling. We may see cardiac arrhythmias due to an imbalance in electrolytes.

And because they're losing blood in their urine and the kidneys aren't making erythropoietin like they normally would we could see the patient develop anemia. And obviously the kidneys aren't making enough urine so we're going to see oliguria. It’s called oliguria anytime there's less than 400 mL of urine. We might see uremia, that's a buildup of the waste product urea in the blood. This can cause mental status changes and itchy skin or pruritis. Sometimes the uremia will even  show up on their skin as a white Frost and this is called uremic Frost. The white Frost that shows up on the skin is actually urea crystals that have been deposited on the skin. And remember urea is a waste product formed when the body breaks down proteins. So if the patient has uremia, they definitely need to be put on a low protein diet to reduce the amount of urea that's created.

Another huge thing that we're going to see with the chronic kidney disease patient is hypertension and this is mainly because of the hypervolemia that's going on since you're not getting rid of fluids, you’re retaining those fluids and that's leading to hypervolemia which causes hypertension. The kidney is not getting rid of electrolytes like it should so the electrolytes are going to be high. Sodium could be over 145. Phosphorus over 4.5. Magnesium over 2.5. And the biggie, potassium over 5.0. We want to especially watch the potassium because if it gets too high it could cause cardiac arrhythmias and possibly a heart attack. The one electrolyte that will be low is calcium. Remember phosphorus and calcium have an inverse relationship so since our phosphorus is high the calcium will be low, or less than 8.5 and this will lead to Mineral and Bone disorders like osteoporosis. So the phosphate and calcium will always be opposite of each other.

There are five stages of chronic kidney disease, and this might show up on your test, so it's good to know. These stages are defined by the glomerular filtration rate. Stage one is when the GFR is still above 90, which normal GFR is above 90 so the kidneys are still doing their job, but we're going to start seeing some protein in the urine or proteinuria. Stage 2: the GFR is 60-89 mils per minute. Stage 3, the GFR is 30-59 mils per minute. Stage 4, the GFR is 15 to 29 and we're going to start seeing a severe loss of renal function here. And stage 5 is end-stage renal disease. This is when the GFR is less than 15 mils per minute, so anything less than 15 mils per minute is considered end-stage renal disease. If the patient is in Stage 5 they'll definitely be getting dialysis until they can hopefully get a kidney transplant. So the way that I remember each of those stages and the GFR that correlates with each one is stage 1 GFR is greater than 90 then after that it goes down by 30 in each stage. So stage 2 is 60-89 so 60 is 30 less than 90 and then stage 3, 30-59 stage 4, 15-29. Stage 5, less than 15.  That helps me remember the stages.

What are the causes of chronic kidney disease? The number one cause is diabetes because the high glucose level in a diabetic patient causes damage to the nephrons which decrease their ability to filter the blood. If you think about it high glucose in the blood, that sugar makes the blood really thick and sticky right? It takes a lot of work for the kidneys to filter that thick syrupy sticky blood. The second most common cause of chronic kidney disease is hypertension. Hypertension causes too much pressure on the structures of the kidneys and overtime it makes the kidneys fail because that's just too much pressure to sustain. Some other causes are acute kidney injury that goes untreated. Glomerulonephritis. Autoimmune diseases like lupus: autoimmune disorders can cause chronic kidney failure when the body's immune system begins to attack its own organs. And then finally just getting older affects the kidneys. Starting at age 65, older adults lose 10% more of their renal function every 10 years.

Another risk factors for developing chronic kidney disease besides having diabetes or hypertension is your ethnicity, because African Americans, Asian Americans, and Native Americans are much more likely to develop chronic kidney disease than caucasians.

How can we prevent getting chronic kidney disease? Control the blood glucose levels and the blood pressure, keep that blood pressure under the recommended 120/80. You want to maintain a healthy weight and don't smoke. Control your diabetes if you have diabetes and decrease your salt intake.

Looking at Diagnostic and lab tests for chronic kidney disease, one of the first things that they're going to look at is the serum creatinine level. This is an early sign of decreased kidney function and as it gets worse, that blood creatinine and also the BUN level will rise. So anything over 1.3 is not good for the kidneys so just think over 1.3 equals sick kidney. they also test your BUN levels normal BUN or blood urea nitrogen level is somewhere between 7 and 20, so if you've got kidney disease, your BUN’s going to be higher than 20. They’ll look at a urinalysis. The urinalysis will pick up any protein or blood in the urine. I used to work in the medical lab and we knew if someone gave us a urine sample and it looked foamy, like it had a bunch of bubbles on the top that they probably had a lot of protein in their urine, which is a sign of kidney problems. Also, if they’re urine looked like the color of tea or watered down Coca-Cola, then it probably had blood in it.

The patient will also need to do a creatinine clearance test. This is when they have to do a 24 hour urine test. They’re given a giant jug to collect all of their urine in for 24 hours except for that very first urine that they have to discard, but after that they collect it for 24 hours and then they're going to compare that 24-hour urine sample to the creatinine level in the blood. So  they compare the creatinine level in the urine to the creatinine level in the blood to give them the creatinine clearance level.

I've already mentioned the GFR: that's glomerular filtration rate. That's another one of the main things that's looked at with chronic kidney disease. The GFR shows how much blood can be basically washed by the kidneys each minute. How much blood is filtered through the kidneys each minute. A normal GFR is more than 90 mls per minute. Anything less than 60 means the kidneys are not working right and anything less than 60 qualifies as chronic kidney disease. Anything less than 15, we say is end-stage renal disease. That's when they need dialysis and possibly a kidney transplant right away.

Some other diagnostic tests that may be done are an ultrasound of the kidneys, a CT scan, and a kidney biopsy. The patient may possibly get an ABG done or arterial blood gas test to assess for metabolic acidosis. They could have metabolic acidosis because of all of the waste products that are building up in the blood. Remember, if you see a pH of less than 7.35 with a bicarbonate level less than 22, that means metabolic acidosis. 

All right, so what are some treatment options that are commonly used to manage chronic kidney disease? If the Kidney disease has progressed to Stage 4 or Stage 5, the patient will most likely be put on dialysis dialysis. Dialysis is where patients are hooked up to machine that does the job of the kidneys. So the machine filters the waste products and the extra fluid out of the blood because the kidneys can't do it themselves. The two main types of dialysis are hemodialysis and peritoneal dialysis, and I'm not going to go too much into dialysis cause that could be a whole separate podcast, but hemodialysis is probably the one that you typically think of when you think of dialysis. That's where the patient goes into the dialysis lab about three times a week to get the impurities removed from their blood. Peritoneal dialysis is a little different. It can be done from home, and it uses the lining of the abdomen as a filter to remove the waste products from the body and this can be done daily which actually helps keep the levels of waste products and electrolytes stay more consistent. Dialysis is not a long-term solution; eventually the patient will need a kidney transplant if they can get it.

The patient with chronic kidney disease will most likely be put on some kind of blood pressure medication to keep their blood pressure down. Usually it’ll be an Ace inhibitor or an ARB, Angiotensin receptor blocker, because those two antihypertensives also give some level of protection to the kidneys. 

Remember I said that the kidneys are responsible for making erythropoietin, the hormone that stimulates The bone marrow to start making new red blood cells. If the kidneys aren't working then they're not making the erythropoietin, so the doctor will probably prescribe some erythropoietin subq injections for the patient so they can make some more red blood cells and this will help decrease their anemia. They may also be given iron supplements to combat anemia.  The medication kayexalate may be given if the patient has hyperkalemia because the kayexalate binds to the potassium and excretes it through the stool. So if they have hyperkalemia then they might get kayexalate to lower the potassium levels.

So What are some nursing interventions that we will do for these chronic kidney disease patients? We're going to monitor their vitals. Assessing is our number one job, so we're going to monitor their blood pressure, especially because high blood pressure is hard on the kidneys. We're going to keep their blood sugar in check. A lot of these patients have diabetes and they're going to have high blood sugar, so you want to keep that blood sugar within normal ranges. 

You will auscultate the heart and the lungs listening for abnormal sounds. For the lungs, we’re mainly listening for crackles. And if crackles are heard, that can mean the patient has pulmonary edema. As nurses, we will monitor their EKG with the bedside monitor. If their potassium levels are high, what are you looking for on the EKG? What's a big warning sign if they have high potassium? A tall peaked T wave. If you see a tall peaked T wave on the EKG then that is an abnormal finding due to them having hyperkalemia. We also want to monitor Labs like the GFR. Remember, a GFR less than 60 indicates kidney disease. Less than 15 equals kidney failure. And we also want to monitor for albumin in the urine which would be termed proteinuria. We’ll monitor their I’s &O’s, and anything less than 400 mls in a 24 hour period, we would call oliguria.  We're going to take daily weights at the same time every morning using the same scale and 1 kg equals 1 liter of fluid so this will warn us of any fluid volume overload and possible hypertensive crisis. We may need to restrict their fluids to prevent fluid overload. and if the patient is on dialysis we need to check that access site to make sure that it's functional. So if they have an AV fistula or an AV graft we need to make sure that we check that access site to make sure it’s clean, and that we can feel a thrill when we palpate it, and that we can hear a bruit when we ausculate it. 

What kind of education do we want to give the patient with chronic kidney disease? We want to teach the patient about the renal diet, which is the diet that they should be following. The renal diet is low in protein and low in sodium. It’s low in protein because the process of breaking down protein makes a lot of nitrogenous waste. We want to make sure they're not getting too much sodium because that can make them retain even more water. They should also avoid any canned and packaged Foods as well as processed Meats because those have a lot of extra sodium in them. The renal diet is also low in phosphate and the patient may be prescribed a phosphate binder to take with their meals. This is a medication that will bind the phosphate in their food and then excrete it in the stool so it doesn't go into their bloodstream. That's a phosphate binder. We want to teach them to avoid foods that have a lot of potassium in them. so no bananas, spinach, strawberries, avocados or potatoes. Also avoid drugs that can cause kidney injury. This seems obvious since the kidneys are already injured, but we don't want them to take any NSAIDs or undergo a procedure that uses a CT contrast dye. No antacids, and to avoid the antibiotics vancomycin and Gentamicin since those can cause kidney injury. 

Alright, let’s do a quick case study to put this information into practice.

Mr. Bean is a 56 year old male with a history of type 2 diabetes, hypertension and osteoarthritis. He presented to the ED with complaints of pruritus, nausea and lethargy. The ED nurse found crackles in his lungs and edema in his lower extremities. He's now been admitted to your unit.

What stands out to you about Mr. Bean? 

Hopefully the diabetes and hypertension stands out to you, since we know those are the two main causes of chronic kidney disease. Pruritis is itchy skin, and can be caused by a buildup of urea in the blood. The patient is lethargic. That could be due to anemia, either because they're losing blood in their urine or they don't have enough red blood cells to carry oxygen because the kidneys aren't making erythropoietin. The nurse heard crackles in his lungs. This tells us he most likely has pulmonary edema caused by excess fluid in the lungs. He's got edema in his lower extremities so I'm already thinking, does he have protein in his urine? The edema could be due to the loss of albumin throwing off the oncotic pressure.

What diagnostic tests would you expect the doctor to order on this patient? 

So we could probably expect a urinalysis to be done. I would expect a CMP comprehensive metabolic panel To test for electrolytes, creatinine, BUN, and blood glucose levels. I would also expect a CBC done, or complete blood count, to look at the numbers of red blood cells and the hemoglobin and hematocrit numbers to check for anemia. And we may also see the doctor order an ABG, or arterial blood gas, to test for metabolic acidosis.

Alright, that’s it for Chronic Kidney Disease. I hope that was helpful to you, and I hope you totally rock your next exam. Have a great week, and I’ll talk to you next time.