The Centers for Disease Control and Prevention estimates that around 37 million adults in the United States have chronic kidney disease, with the majority being undiagnosed. This is because it can take some time to find out that you have chronic kidney disease. After all, chronic kidney disease doesn’t usually have symptoms until it’s already at an advanced stage, and even then the symptoms – like nausea, fatigue and muscle cramps – aren’t unique to kidney disease.
But if you have those or other unexplained symptoms, a chronic health condition or a family history of kidney disease, it’s worth seeing an expert. Doctors can test for chronic kidney disease early, and while it generally can’t be reversed, it can be managed effectively. Below, we explain what chronic kidney disease is, who’s most at risk, how it’s treated and more.
What is chronic kidney disease?
Chronic kidney disease (CKD) refers to when damage to the kidneys gradually lessens their ability to function.
The kidneys filter all of the blood in your body to remove waste, toxins and excess fluid. They regulate the amount of water and minerals (like sodium and potassium) in your blood, and produce hormones that help with controlling blood pressure, producing red blood cells and bone health. So when the kidneys are damaged, it can lead to a range of complications throughout the body.
The five stages of chronic kidney disease
The kidneys are strong enough to keep functioning well even after they’ve started getting damaged, which is why CKD generally doesn’t start with symptoms. Doctors categorize CKD into five stages according to the kidneys’ estimated glomerular filtration rate (eGFR), which is a measurement of how much creatinine (a waste product) is in your blood. The more damaged your kidneys are, the more creatinine stays in your blood rather than getting filtered out. This corresponds to a descending eGFR score.
- Stage 1 CKD (eGFR of 90+) – Mild damage. At this stage, the kidneys still have normal function.
- Stage 2 CKD (eGFR of 60-89) – Mild damage and adequate (but not ideal) function.
- Stage 3 CKD (eGFR of 30-59) – Mild to moderate damage. At this stage, kidney function has become compromised. People at this stage may develop complications of kidney disease, such as anemia, bone disease or electrolyte disorders.
- Stage 4 CKD (eGFR of 15-29) – Severe damage. At this stage, the kidneys are approaching failure. This is sometimes when people start to experience symptoms.
- Stage 5 CKD (eGFR of 15 or less) – The kidneys are very near or at the point failure. This is when treatments like dialysis or a kidney transplant may become necessary.
Chronic kidney disease is often caused by other health conditions
It’s possible for the kidneys to become damaged by blockages, kidney stones or other isolated, short-term issues. But the majority of kidney damage is caused over time by other health conditions that create inflammation or other issues in different parts of the kidneys. The most common examples include:
- Diabetes – A high amount of sugar in the blood, which occurs with uncontrolled diabetes, can damage the kidneys’ filtering systems.
- High blood pressure (hypertension) – Uncontrolled high blood pressure can damage your blood vessels, including those in the kidneys. This can affect the kidneys’ ability to remove waste and excess fluid from the blood. The resulting buildup of fluid can cause blood pressure to increase further.
- Infections – Certain viral infections, such as hepatitis B and C, as well as Human Immunodeficiency Virus (HIV), can cause damage to the kidneys’ filters and other tissues. Certain bacterial infections, such as strep throat, can cause acute inflammation in the kidneys.
- Glomerulonephritis – This is a collection of a variety of conditions that can cause inflammation in the filters and/or the tubules of the kidneys, which can lead to progressive chronic kidney disease. These are typically only diagnosed via kidney biopsy and can involve treatment with specialized medications.
- Polycystic kidney disease (PKD) – PKD is a genetic disorder in which cysts grow in the kidneys. These cysts can change the shape of the kidneys or enlarge them, which can affect their ability to function.
- Other autoimmune disorders – Lupus, Goodpasture syndrome and other disorders in which the body’s immune system attacks healthy cells in the body can all contribute to kidney damage.
Other risk factors for chronic kidney disease
In addition to health conditions, there are lifestyle and medical factors that are associated with an increased risk of kidney damage and CKD. These include:
- A family history of kidney-damaging conditions or kidney disease
- Age, particularly after age 60
- A history of urinary infections
- Overuse of medications that can be toxic to the kidneys, such as ibuprofen, naproxen and aspirin
- Being overweight
- Smoking
The kidneys can still do their job for a while before damage significantly interferes with their function. But once you’ve reached around stage four or five of CKD, the buildup of waste products and fluid in your blood can cause a variety of symptoms. Many of these symptoms are not unique to CKD, which is why it’s important to see a doctor if you’re experiencing them – especially if you have any of the risk factors listed above.
Symptoms of moderate to severe CKD can include:
- Altered taste
- Appetite loss
- Chest pain
- Fatigue or weakness
- Feeling cold frequently
- Itchiness
- Mental fogginess
- Muscle cramps or twitches
- Nausea or vomiting
- Shortness of breath
- Swelling in the ankles and feet
- Trouble sleeping
Kidney disease is diagnosed using blood, urine and imaging tests
In addition to testing your blood to determine your kidney function, your doctor may use a few other tests to find out if you have CKD and how advanced it is if you do. This may include urine tests to look for filtration issues, indicated by blood cells or albumin (a protein that normally stays in the blood). Urine tests can also help indicate possible causes of kidney issues, such as diabetes, kidney stones or infections.
Finally, your doctor may also order an ultrasound or other imaging test to look for structural issues in your kidneys and to assess the flow of blood through them.
Treatment for kidney disease focuses on managing kidney health
Kidney damage can’t be reversed, so CKD tends to become progressively worse over time. However, it’s possible to slow that progression significantly through a combination of lifestyle changes and medical treatments. Lifestyle changes include:
- Controlling chronic health conditions like diabetes and high blood pressure
- Maintaining a healthy weight
- Getting regular physical activity
- Eating a kidney-friendly diet, which typically involves limiting calories and sodium, as well as some other electrolytes and protein in certain cases
- Stopping smoking and reducing or stopping alcohol consumption
Medical treatments for CKD can include:
- Certain blood pressure medications, which may help slow the progression of CKD even in people without high blood pressure
- Diuretics to help reduce salt and excess fluid in your blood
- Medicines to help manage cholesterol, prevent anemia or support bone health
- Regular visits with a kidney specialist (nephrologist) to monitor kidney function
Later-stage CKD treatments
If you reach a later stage of CKD and your kidneys start to show signs of failure, you’ll need a more involved form of treatment. There are two main options:
- Dialysis is when a specialized machine or solution is used to filter waste and excess fluid from your blood.
- Kidney transplant involves surgically implanting a healthy donor kidney.
Talk to a doctor if you think you might have chronic kidney disease
If you think you might be experiencing symptoms of CKD or believe that you’re at risk of developing it, talk to a doctor. Knowing whether or not you have CKD is important information to have about your health. And the sooner you can start taking steps to manage CKD, the better. Your primary care doctor can help you with the initial testing and recommendations, and will refer you to a kidney health specialist if necessary.
