Kidney disease is also called chronic kidney disease and it is a progressive condition with accumulated damage to the kidneys occurring over the span of years. This is in contrast to an acute injury to the kidney, caused by physical damage a medication, or other factors. Kidney disease is often caused by other chronic health conditions like high blood pressure and diabetes.
The problem of kidney disease is growing in the U.S. and it leaves millions of people sick and needing regular medical care. While certain chronic conditions that cause kidney disease can be treated or prevented, there are also medications people may take that they do not realize may contribute to kidney disease. These include cholesterol-lowering drugs like Crestor, and type 2 diabetes drugs like Byetta.
Kidney Function and Dysfunction
The purpose of the kidneys is to filter waste products from the blood, as well as extra water, and to send both out of the body in the form of urine. Inside of the kidneys, which are bean-shaped organs in the middle of the back to each side of the spine, are millions of nephrons, small filtering units. Each nephron filters a small amount of blood by allowing small waste products and fluid pass through and catching blood cells and larger molecules and sending them back into the blood stream. Each kidney filters between 120 and 150 quarts of blood per day.
When the kidneys are not working properly, waste products build up in the bloodstream and electrolytes like sodium and potassium become imbalanced, which can cause health problems. The kidneys are also responsible for producing hormones that are necessary for regulating blood pressure, maintaining bone density, and making blood cells. When the kidneys fail, many problems arise, and ultimately, without working kidneys a person will die.
Causes of Kidney Disease
Kidney disease is the gradual loss of function of the kidneys. If diagnosed in early stages, this disease can be treated, but symptoms early on are mild or non-existent. The disease is progressive and will get worse over time, but this can be slowed or stopped if the underlying cause is known and is treatable. Unfortunately the cause is not always known or the kidney disease is discovered too late to make a significant difference with treatment.
The most common cause of kidney disease is diabetes, either type 1 or type 2. Type 2 diabetes is much more common and it is on the rise, putting millions of people at risk for kidney disease. Chronically high blood pressure is another common cause of kidney disease. Less common causes include inflammation in the filtering units of the kidneys, interstitial nephritis, another type of inflammation in the kidneys, polycystic kidney disease, recurring kidney infections, and obstruction of the urinary tract, which can be caused by tumors, kidney stones, or an enlarged prostate.
There are several known risk factors for kidney disease and if you can control or prevent those, you can significantly reduce your risk of developing this chronic condition: high blood pressure, diabetes, cardiovascular disease, obesity, and smoking. Factors that cannot be controlled include being older, being African-, Asian-, or Native American, and having abnormal kidney structures.
Kidney disease progresses slowly and in the early stages there may be no troubling symptoms. As the damage progresses and gets worse a person may start to experience more symptoms. These include nausea and vomiting, appetite loss, difficulty sleeping, fatigue, muscle cramping and twitching, swollen feet and ankles, changes in urine output, persistent itchy skin, chest pain, shortness of breath, and high blood pressure. Many of these can be caused by other conditions so diagnosing kidney disease is not always straightforward.
Complications of Chronic Kidney Disease
Unfortunately, many people with kidney disease do not experience many symptoms or get a diagnosis until the disease is advanced and the damage to the organs is irreversible. Because of this, many kidney patients will experience the complications of the disease, which can impact all parts of the body: fluid retention, cardiovascular disease, weakened bones and fractures, anemia, sexual dysfunction, pregnancy complications, infections due to an impaired immune system, central nervous system damage, and hyperkalemia, high potassium levels that can be life-threatening.
Diagnosis and Treatment
If you have any signs of kidney disease, especially if you have risk factors like diabetes, diagnosis will include blood and urine tests. Blood tests can check for high levels of waste products and urine tests can check for abnormalities characteristic of poor kidney function. An imaging test like an ultrasound can help determine if there are structural abnormalities. In some cases, a doctor may take a small needle biopsy of a kidney for further testing.
One of the most important ways of treating kidney disease is to treat the underlying condition. For instance if you have type 2 diabetes, you may need to make lifestyle changes or take medication to control blood sugar levels, which will slow or halt kidney damage. Treating the cause is the only real way to slow or stop kidney disease, but in some cases the damage is too far gone to accomplish this.
In addition to trying to treat the cause of kidney disease, most patients will also receive treatment for complications. This may include things like hormone supplements, drugs to lower blood pressure or to reduce swelling or strengthen bones, or following a low protein diet to minimize the amount of waste that needs to be filtered by the kidneys.
Later-stage kidney disease is when one or both kidneys are no longer able to maintain enough filtering and clearing out of waste and fluids from the body. When this happens, a patient can receive one or two types of more drastic treatment. One is to have a kidney transplant to replace one kidney with a healthy kidney from a donor. Another type of treatment, which can be used while a patient waits for a donor kidney, is dialysis.
There are far more people waiting for kidneys for transplants than there are kidney donors, which means that many people must live out the rest of their lives with regular dialysis treatment. According to the National Kidney Foundation, 468,000 Americans are on dialysis. Dialysis is not comfortable and it is very restricting. It requires three to four hours of time for a session, usually three times per week. Only 35 percent of end-stage kidney patients are alive after five years of dialysis.
Dialysis is a treatment that filters the blood of a patient whose kidneys can no longer do it. When kidney function is down to ten to fifteen percent, dialysis becomes necessary. There are two types of dialysis and hemodialysis is the much more common type. Hemodialysis uses a machine to act like an artificial kidney. Blood is transferred from the body, sent through the machine, and then back into the body. Peritoneal dialysis is much less common and involves filtering the blood inside the patient’s abdominal cavity.
Several chemicals are used during hemodialysis and these supplement the filtering of the machine, but sometimes these medications can cause problems. GranuFlo and NaturaLyte are two products made by Fresenius, a German company that provides much of the dialysis equipment used in the U.S. These products are used to neutralize excess acid in the blood.
In 2011 Fresenius sent an internal memo to warn dialysis professionals that there GranuFlo and NaturaLyte might contain more of the active ingredient than they realized. This put patients at risk for of sudden death by being given an overdose. The company has faced lawsuits over it because it only warned Fresenius dialysis centers although their products were used in other clinics.
The Effects of Type 2 Diabetes Drugs on the Kidneys
Type 2 diabetes and kidney disease are closely connected. Diabetes is the most common cause of kidney disease, but drugs used to treat it can also cause kidney damage. Multiple type 2 diabetes drugs carry warnings regarding kidney damage, including Invokana, Benicar, Farxiga, and Glyxambi. People who already have kidney failure are not supposed to use these medications, but because the two conditions are related, this can present a problem.
The reason that some of these medications cause kidney damage is that they control blood sugar levels by acting in the kidneys. For example, Glyxambi is an SGLT-2 inhibitor. It inhibits the action of a protein that is involved in filtering glucose out of the urine and sending it back into the bloodstream. This action lowers blood sugar levels, but may also cause damage to the kidneys.
Kidney disease is a serious problem in the U.S. Some estimates say that one in three adults is at risk for developing it. Because there are no early symptoms too many people don’t realize they have kidney disease until the damage cannot be reversed. If you have any risk factors for kidney disease, take steps to mitigate them and be aware of the drugs that can damage your kidneys.