You probably know the kidneys for their distinctive shape. They are the bean-shaped organs on either side of your spine, behind the belly, and below the ribs. They play a very critical function in filtering your blood of extra fluid, toxins, and waste products, a process that's vital for your overall body health.
Blood passes through the kidneys about 40 times a day. Kidneys remove waste, maintain the appropriate electrolytes levels, and control fluid balance in the body. The cleaned blood then flows back into the body while the waste is turned into urine and drains via the ureter to the bladder.
Kidney disease refers to damage to the kidneys that causes them to not filter the blood effectively. The damage could be due to diabetes, high blood pressure, and other chronic conditions. If the disease worsens over time, the kidney(s) may stop functioning completely.
Chronic kidney disease
Chronic kidney disease is a common form of kidney disease often caused by high blood pressure. The condition has to be present for three months or more to be considered chronic kidney disease. A person can normally live for several years with this disease, but the kidney's ability to filter blood declines.
If you're diagnosed with end-stage kidney disease, you'll have to undergo dialysis, during which a machine helps filter extra fluid and waste out of the blood. You may also need to undergo a kidney transplant depending on the circumstances. Dialysis and kidney transplants are reserved for patients whose kidneys are nonfunctioning; many kidney disease patients are not in this category.
Most chronic kidney disease cases occur due to diabetes and high blood pressure.
In a diabetic, the blood sugar is too high and damages nerves, blood vessels, and kidneys. On the other hand, high blood pressure occurs when the blood pressure against the blood vessel's walls increases, and if poorly controlled or uncontrolled, it may lead to kidney disease.
Polycystic kidney disease
Polycystic kidney disease develops when a cluster of fluid-filled sacs form in the kidneys and interfere with their ability to filter blood. As the cysts grow, the kidneys enlarge and may fail after some time. These cysts may also form in other organs such as the liver.
Kidney stones are hard deposits of salts and minerals that form inside the kidneys. These stones often form when urine concentrates, and the minerals crystallize. As a result, you may feel pain as you pass urine. However, if recognized early, kidney stones won't cause permanent damage.
Glomerulonephritis is a condition of the glomeruli, in which the tiny filters in the kidney become inflamed and swell. This disease can occur on its own or as part of another condition such as diabetes or lupus. Glomerulonephritis can either be acute or chronic.
Acute glomerulonephritis develops suddenly, typically after skin or strep throat infection, and may heal on its own. However, sometimes the kidneys may stop functioning, and you need to get the right treatment quickly.
Chronic glomerulonephritis could be genetically inherited, rarely, and often appears in male teens with hearing or vision loss, a condition called Alport syndrome. It develops silently over several years without symptoms and usually leads to complete kidney failure.
Urinary tract infections
Urinary tract infections (UTIs) are urinary system infections and can affect the kidney, bladder, and urethra.
Urine, a byproduct of blood filtration by the kidney, should not normally contain bacteria. It is composed of excess water and waste products that are removed from the blood by the kidney. Urinary tract infections occur when bacteria from outside the bladder enter the urinary system and cause infection and inflammation.
Commonly, the bacteria Escherichia coli (E. coli) causes urinary tract infections; this bacteria is found in the gastrointestinal tract.
Kidney disease affects approximately 15% of adults in the U.S.¹ That is about 37 million people. The disease is more common in people with hypertension (one out of five people) or diabetes (one out of three people).
Unfortunately, despite the disease being prevalent in the country, up to nine people out of ten are not aware they have the disease.
According to a 2021 report² released by the CDC on the prevalence of kidney disease based on gender and age, kidney disease is more prevalent in women (14%) than men (12%).
In terms of age, it is more common in people 65 years or older (38%). The prevalence among individuals aged 45-64 is 12%, and people between the age of 18 and 44 records the lowest prevalence of 6%.
Kidney disease reduces the life expectancy of individuals depending on factors such as the stage of the disease, patient’s age, and underlying medical conditions. Therefore, life expectancy and survival rates only give a general outlook but are not a guarantee.
Testing can detect kidney disease before any significant damage occurs in the early stages (stages one and two). In stage five, dialysis becomes necessary. The average life expectancy for a person on dialysis is five to ten years³, but some patients can live for more than 20 years.
Kidney disease symptoms include:
Trouble thinking clearly
Fatigue (feeling tired)
Anemia (decreased production of red blood cells)
Shortness of breath
Feeling faint, dizzy, or weak
Feeling very itchy
Swelling in hands or feet
Swollen or puffy face
Upset stomach, nausea, vomiting
Getting up during the night frequently to urinate
Kidney disease symptoms differ depending on the stage of the kidney disease. During the early stages, one, two, and three, the kidneys may still filter waste out of the blood. In stages four and five, blood filtration may overwhelm the kidney, and they stop working altogether.
The symptoms are as follows according to the stage:
Stages one and two
You may have no symptoms in stage one since the kidneys can function at 90% or better. But in stage two, a person may experience nonspecific symptoms, such as fatigue, sleep problems, weakness, itching, and loss of appetite.
In stage three, symptoms may include fatigue, loss of appetite, persistent itching, sleep problems, swelling of the hands and feet, frequent urination, and general body weakness. Also, you may develop complications such as bone disease, anemia, and high blood pressure.
Stage three symptoms recur in stage four together with other symptoms such as back pain, chest pain, decreased mental sharpness, muscle twitches or cramps, nausea and vomiting, persistent itching, and shortness of breath.
In stage five, the kidney functions at a capacity of less than 15%, or you may have complete kidney failure. At that point, waste and toxins accumulate in the body and become life-threatening. At this stage, if not before, your doctor may discuss starting dialysis treatment.
You may not notice the signs of kidney disease until they become severe. But below are the typical first signs of kidney disease:
Puffiness around the eyes when you wake up
Dry, scaly skin
Frequent urination, particularly late at night
Kidney failure means the kidney can no longer function well enough to keep your body free of toxins and waste product accumulation. As the kidney function deteriorates, you may experience the following symptoms:
Nausea and vomiting
Not feeling hungry
Swelling in your feet and ankles
Trouble catching your breath
In the case of acute kidney failure (where the kidneys stop working suddenly), you may experience the following symptoms:
If you have kidney disease, you may experience complications in other parts of the body.
Some common complications¹ include:
This condition occurs when the kidney does not make sufficient erythropoietin hormone. Therefore, it fails to make enough red blood cells to transport oxygen.
Heart disease affects the heart or blood vessels. Kidney disease may lead to heart concerns.
High blood pressure (hypertension)
Hypertension occurs when the pressure of the blood pumping through the blood vessels increases. It can worsen kidney function, cause fluid retention, and the high blood pressure itself may become more difficult to control, even with medication.
When damaged kidneys fail to filter uric acid effectively, its buildup in the joints causes this type of joint pain.
A person with inefficient kidney function may have reduced blood calcium, increased phosphorus levels, and weakened bones. As a result, you may suffer from bone fractures.
Fluid builds up in the body of a person with kidney disease, causing the limbs to swell, and your lungs may fill with fluids.
People with kidney disease may experience a sudden increase in potassium levels, affecting heart function.
This happens when excess acid in the accumulating bodily fluids destabilizes the body’s pH balance. As kidney disease worsens, you may have other problems such as muscle or bone loss and endocrine disorders.
Waste products accumulate in the blood of a patient with a damaged kidney and may cause symptoms such as nausea, fatigue, sleep disturbances, and restless legs.
Some possible causes include:
High blood pressure
Hardening of arteries
Inflammation of the kidneys (nephritis). This occurs due to an infection or autoimmune response where the body's immune system attacks and damages the kidneys.
Medications that are toxic to kidney tissue or block the system that drains the kidneys.
Some kidney diseases like polycystic kidney disease result from problems with the size or shape of the kidneys.
Diabetes is the leading risk factor for developing kidney disease. But there are other risk factors such as:
Abnormal kidney structure
High blood pressure
Heart (cardiovascular) disease
Regular usage of medications that can damage the kidneys
Being Black, Asian American, or Native American
Family history of kidney disease
Before diagnosing kidney disease, the doctor will first determine whether you have any risk factors for developing the disease. After that, various tests are administered to determine whether the kidneys are working properly.
Kidney diagnosis tests include:
Glomerular filtration rate (GFR)
This test measures how well the kidneys are functioning and establishes the stage of kidney disease.
A kidney biopsy involves removing a small piece of the tissue from the kidney while you're under anesthesia. The sample tissue helps the doctor establish the type of kidney disease you may have and the extent of the damage.
Blood creatinine test
Creatine molecules present in the muscles break down to produce a waste product, creatinine. The levels of this waste product are higher if the kidneys are not functioning properly.
Ultrasound or computed tomography (CT) scan
Ultrasound and CT scans give a clear image of the kidneys and urinary tract. With the images, the doctor can see if the kidneys are too large or small. Also, the pictures can reveal any tumors or structural issues that could be present.
The doctor may ask for a urine sample to test for albumin, a protein that people with damaged kidneys may pass into the urine.
High blood pressure increases the likelihood of developing kidney disease. Therefore, the doctor may prescribe blood pressure medication. These include angiotensin-converting enzymes (ACE) inhibitors such as captopril, ramipril, lisinopril, and fosinopril.
Your doctor may also prescribe angiotensin receptor blockers (ARBs) such as losartan, valsartan, azilsartan, irbesartan, eprosartan, and olmesartan. These medications control blood pressure and lower the amount of protein in the urine, which could help your kidney over time.
For diabetics, the doctor may prescribe dapagliflozin to slow kidney disease, even to people without diabetes. Also, you may need medications that help the body make erythropoietin. This chemical prompts the body to produce red blood cells, which transport oxygen. For this purpose, the doctor may prescribe darbepoetin alfa to curb anemia.
Making dietary changes is as important as taking medication. Your doctor may put you on a special diet with lower potassium, sodium, phosphate, and protein levels. Such a special diet ensures the kidneys don't have to function as hard to get those nutrients and minerals out of the blood.
Also, the doctor may advise you on the specific amounts of minerals and vitamins to take, such as calcium and vitamin D.
People with diabetes should choose foods that keep their blood sugar levels under control. They should reduce their intake of high cholesterol foods and consider healthy diets that include whole grains, fresh fruits, and vegetables. Additionally, controlling diabetes via oral medications or insulin injections is crucial. Those with hypertension should also cut back on salt intake.
If the kidneys are no longer functioning adequately, dialysis is usually needed. It is an artificial method of removing waste products from the blood. There are two types of dialysis; hemodialysis and peritoneal dialysis.
This type of dialysis uses a machine fitted with a mechanical filter to help remove waste products from the blood. This is a process that is usually performed at a dialysis center three days per week.
Before starting hemodialysis, you will need a procedure to enable the dialysis machine to access your veins and filter your blood. This type of intravenous access is called a fistula and is usually placed in the upper arm.
This access needs a few months to heal before a person can start hemodialysis. But, if the patient needs to start dialysis earlier than that, the surgeon may make a synthetic graft rather than a fistula.
In situations where the patient needs dialysis urgently, the surgeon may consider a dialysis catheter that is placed into the jugular vein in the neck and can be used immediately.
The blood flows through the dialysis machine for cleaning and pumps it back into the body. That may take several hours.
Hemodialysis has possible side effects; the most common are itching, muscle cramping, fatigue, and low blood pressure.
This form of dialysis is a bit different from hemodialysis in that it uses the peritoneal membrane in the abdomen to clean the blood. The surgeon inserts a tube into the abdominal cavity, through which dialysis fluid (dialysate) flows via the tube and into the abdomen. It is this fluid that collects waste products and drains them out over a number of hours. Peritoneal dialysis is usually performed by the patient in their own home.
Automated devices that can perform the peritoneal dialysis procedure overnight are available and allow you to do your usual activities during the day. The side effects of peritoneal dialysis include infections in the area where the tube inserts.
Some lifestyle changes can help manage kidney disease. These include:
Limiting alcohol consumption
Increasing physical activity
You cannot reverse kidney damage, but taking several steps in the early stages can slow it down. For example, eating a healthy diet, engaging in routine physical exercise, and taking the medications prescribed by your doctor.
Patients with late-stage kidney disease may require dialysis until they receive a kidney transplant.
If you qualify for a kidney transplant, you will receive a healthy kidney into your body from a living or deceased donor such as a family member, friend, or stranger. The donor’s kidney is matched to the recipient based on blood type, tissue type, antibodies in your blood, age, and kidney size.
It is worth noting that a kidney transplant is not a cure but a treatment. You'll need to take antirejection and other drugs essential to maintain the transplant and to prevent the rejection of the kidney for the rest of your life.
Just like the heart, liver, and lungs, your kidneys are vital organs. For this reason, you should take all possible measures to prevent kidney damage.
The main causes of kidney abnormalities are high blood pressure and diabetes. When you work to manage these problems, you will be on track to prevent kidney disease.
You can do the following to lower the risk of developing kidney disease:
Control your blood pressure
Eat a healthy diet
Manage your blood sugar
Reduce salt intake
Drink enough water
Avoid overuse of pain medication
Kidney disease may not be apparent in its early stages. People with key risk factors such as diabetes, hypertension, and a family history of kidney disease should undergo regular screenings for the disease.
Regular checkups help keep track of how the kidneys are functioning and allow early detection of the disease so you can take steps to slow it down.
Nephrologists are renal health experts who work to identify problems with the kidneys and help maintain good health. They perform diagnostic tests and treat and manage kidney diseases. They also treat related issues such as fluid retention, high blood pressure, and electrolyte and mineral imbalances. A nephrologist is also in charge of dialysis treatment, kidney treatment, and follow-up visits.
Apart from nephrologists, other health care professionals have their special roles in making the diagnosis and treatment process a success.
Renal dietitians help patients with kidney disease plan their meals, so they avoid excessive protein and potassium. They have the skills to customize solutions to meet the unique needs of every patient, with the overall objective of promoting the best nutritional intake for the patient's optimal health.
Nephrology social workers are certified licensed health professionals who help patients and their families cope with kidney disease. They also help patients to plan a treatment that fits their activities and lifestyle.
These two technicians maintain dialysis machines, order dialysis supplies, and start and end dialysis treatments. They work under the supervision of a nephrologist.
Candidates for a kidney transplant meet a health care team comprised of a transplant surgeon, clinical transplant coordinator, and donor coordinator. Donor coordinators serve patients waiting to have a transplant. They obtain consent from the donor's family and maintain, distribute, preserve, and transport organs for transplantation.
Clinical transplant coordinators assist patients in preparing for the transplant. For example, they schedule tissue typing tests, educate patients and families about the benefits and risks of the procedure, schedule operations, and arrange checkups. They are the link between the patient and transplant hospital.
Transplant surgeons perform transplant operations and respond to any questions a person may have about the surgery. They work with kidney doctors to make follow-up visits after the surgery.