What Are the Signs of Kidney Disease?

About 90% of people with kidney disease don't realize that they have it. This may be because signs of kidney disease often don't appear until the very late stages, David Goldfarb, MD, clinical chief of nephrology at NYU Langone Health in New York City, told Health.

For this reason, it's important for people with risk factors for kidney disease—such as being over age 60 or having a chronic medical condition such as type 2 diabetes, high blood pressure, or an autoimmune disorder like lupus—to get routinely screened for kidney disease, Dr. Goldfarb said.

However, there are subtle symptoms that can show up both in the early and later stages, Staci Leisman, MD, a kidney specialist at New York's Mount Sinai Hospital, told Health. Here are some signs to look for at various stages of kidney disease.

Early Signs of Kidney Disease

Certain symptoms can crop up in the first three stages of kidney disease before too much damage has been done to your kidneys, Dr. Leisman said. These symptoms can show up in the later stages, too. Whenever you notice them, see your healthcare provider as soon as possible to check for kidney disease.

Symptoms that may appear early include:

Anemia

One of the earlier signs of kidney disease is actually anemia. Healthy kidneys make a hormone called erythropoietin (EPO), which signals your body's bone marrow to make more red blood cells. If your kidneys aren't working as well as they should, they won't make enough EPO. As a result, you produce fewer red blood cells.

"We often see this in the middle stages of kidney disease," Dr. Leisman said. See your healthcare provider if you have symptoms of anemia such as:

• Body aches
• Chest pain
• Difficulty breathing or shortness of breath
• Dizziness
• Headaches
• Trouble concentrating
• Unusually pale skin
• Weakness and fatigue

Get emergency medical care if you have persistent chest pain, and seek immediate medical attention if you have difficulty breathing or shortness of breath.

Your healthcare provider can run a blood test to check your hemoglobin levels, which is part of your red blood cells.

Treatment is usually iron supplements. In severe cases, red blood cell transfusion may be required.

Erythropoiesis stimulating agents (ESAs) are also commonly used to treat anemia that is caused by kidney failure. ESAs are medications that mimic EPO, thereby signaling to your bone marrow to make more red blood cells.

If you are diagnosed with anemia, Dr. Leisman said it's a good idea for your healthcare provider to run tests to check kidney function, such as your glomerular filtration rate (GFR). This is a blood test to check how well your kidneys filter blood. A GFR of at least 60 is considered normal, while less than that may suggest kidney disease.

"We usually begin seeing anemia when a patient's GFR is in the 30s," Dr. Leisman said.

Bloody or Foamy Urine

If you see blood, it means red blood cells are in your urine. While this could be caused by a urinary tract infection (UTI) or kidney stone, it can also indicate kidney disease.

"When your kidneys are healthy, their filters actually prevent blood from entering your urine," Robert Greenwell, MD, chief of nephrology at Mercy Medical Center in Baltimore, told Health. When they're damaged, they might allow small amounts of blood to leak in.

Sometimes, you may actually see blood (it generally looks either red or like tea or cola, Dr. Greenwell said). In other cases, the blood is microscopic, so it can only be picked up through a routine urinalysis when your healthcare provider looks at a sample of your pee under a microscope.

Passing foamy urine on occasion is normal and could just be due to the force of urine against the toilet water. However, if your urine consistently has white foam, this may indicate high levels of albumin, a protein usually found in small amounts in your urine. It's the same protein that's in eggs, which is why your urine will have that same foamy, egg-white consistency.

"When your kidneys become damaged, one of the first things they have trouble filtering out is protein," Dr. Leisman explained.

Nighttime Peeing

During the day, excess fluid in your body builds up in your ankles and calves from standing and sitting all day, Dr. Leisman said. Once you go to sleep at night, that extra fluid heads straight up to your kidneys.

If your kidneys are damaged, they can't filter that fluid as well. The result may be more nocturnal bathroom trips.

If you're getting up to go to the bathroom more than once in the middle of the night, it's time to pay a visit to your healthcare provider.

Swelling

When your kidneys are damaged, they're not able to filter out salt as well, which can lead to edema or swelling in body parts such as the ankles, feet, and legs.

You may also notice puffiness around your eyes, especially in the morning, which doesn't go away with usual care (such as applying cold washcloths or tea bags).

"Your kidneys are leaking protein into your urine, which means less goes into your blood," Dr. Greenwell said. "The lack of protein can cause blood vessels to swell, which is often most noticeable around your eyes."

Later Signs of Kidney Disease

While some may appear earlier, certain symptoms are more likely to crop up during stage 4 or 5 of the disease. They indicate that your kidneys have become so damaged that they're no longer able to filter out most toxins. As a result, toxins build up in your bloodstream.

At this point, treatment usually involves dialysis or, eventually, a kidney transplant, Dr. Greenwell said. Dialysis is when a machine moves your blood through a filter outside your body, removing wastes.

Symptoms that are more likely to appear in later stages of kidney disease include:

Dry, Itchy Skin

Your kidneys help to keep your bones strong and maintain the right balance of minerals in your blood. During end-stage kidney disease, your kidneys can become so damaged that they can't do either.

As a result, your skin may become rough and scaly and develop an almost fish-like scaling. You may notice that it feels tight and cracks easily.

As your kidney function worsens, your kidneys will stop being able to filter out waste, such as excess amounts of the mineral phosphorus. This can build up in your skin and cause itching—called uremic pruritis—ranging from a mild annoyance to something that interferes with your life. You may scratch so hard that you develop raw, bleeding skin or sores.

Over time, the build-up of toxins in your body can cause your skin to change to an unhealthy pale, yellowish, or gray color. Areas of your skin may darken, and your skin may thicken and develop deep lines, bumps, or cysts that look like whiteheads. You may also notice an itchy rash of small dome-shaped bumps that sometimes join together to create rough raised patches.

Advanced kidney disease symptoms can also appear on your fingernails or toenails. The telltale sign is half-and-half nails, with white on the upper part of your nails and a normal to reddish brown color on the bottom. Nails can also become pale or develop white bands (Muehrcke’s nails).

Fatigue and Trouble Sleeping

According to a 2020 study, an estimated 6.6% to 80% of people who are on dialysis for end-stage kidney disease also develop restless legs syndrome. Restless legs syndrome is a condition where you have an overwhelming urge to move your legs while you're resting.

Sleep, in general, may be more difficult for someone with kidney disease. You may also notice fatigue, weakness, and trouble concentrating in the late stages of kidney disease since the sharp decrease in kidney function leads to a buildup of toxins in your blood.

Loss of Appetite

When you have kidney disease, toxins build up in your body, which can impact your appetite.

About one-third of patients with end-stage kidney disease also report a metallic taste in their mouth, which is most likely due to the buildup of waste products in your body, such as urea. This can impact your taste buds. Loss of taste is common.

Kidney disease can also trigger nausea and vomiting.

Muscle Cramps

When you have severe kidney disease, you're more prone to electrolyte imbalances which can trigger cramping. You may also experience a pins and needles sensation in your arms and legs, Dr. Greenwell said.

A Quick Review

In both early and later stages, the symptoms of kidney disease can be subtle. They can be so subtle, in fact, that most people are unaware they have kidney disease.

If you notice signs and symptoms of kidney problems and disease, see your healthcare provider as soon as possible. They can run blood and urine tests to determine if you have kidney disease. If it turns out you do have it, kidney disease is less likely to progress to kidney failure when detected and treated early.