Chronic Kidney Disease

What is chronic kidney disease?

Chronic kidney disease is long-term damage to the kidneys, the organs responsible for producing urine. Causes of chronic kidney disease include diabetes, hypertension, kidney infections, and inflammatory diseases, medications or toxins, inherited kidney diseases, and prematurity and low birth weight.

Symptoms include swelling (edema) and decreased urine output (oliguria), fatigue, weakness, chest pain, shortness of breath, bone pain, nausea and vomiting, and neurological symptoms.

Diagnosis is made by laboratory tests. Chronic kidney disease is defined by laboratory tests showing evidence of kidney failure, kidney damage, or decreased kidney function for three or more months.

Treatments include dietary changes and medications to treat the symptoms, slow the progression of the disease, and manage complications. End-stage chronic kidney disease (also called chronic kidney failure) requires treatment with renal replacement therapy, which includes dialysis and kidney transplant.

You should make an appointment with your primary care physician to discuss your symptoms as soon as possible.

Symptoms of chronic kidney disease

Chronic kidney disease is defined based on laboratory tests, and some people with early chronic kidney disease may not have any symptoms. In other people, symptoms may be signs of decreased kidney function or complications of chronic kidney disease.

Main symptoms

The main symptoms experienced by those with chronic kidney disease include the following.

• Swelling and decreased urine output: This can occur because the kidneys are normally responsible for producing urine, and kidney damage can lead to decreased urine output and fluid retention in the body.
• Fatigue, weakness, and exercise intolerance: This is due to anemia, or low red blood cell counts because the kidneys are responsible for producing a substance that increases red blood cell production.
• Muscle weakness and paralysis: This is due to possibly high levels of potassium in your blood, as the kidneys are normally responsible for excreting potassium.

Other symptoms and complications

Other symptoms and complications that can occur as chronic kidney disease progresses include the following.

• Chest pain and/or shortness of breath: Having chronic kidney disease increases the risk of developing heart disease, which may cause chest pain or shortness of breath. In addition, fluid overload from decreased urine output may cause fluid to build up in the lungs, causing shortness of breath.
• Bone pain, skeletal deformities, and easy fractures: This is due to a mineral bone disorder that can develop with CKD, in which the normal mineral balance of the bones is disrupted.
• Nausea, vomiting, and loss of appetite: A life-threatening condition called uremia may cause these symptoms in the early stages. Uremia is caused by the inability of the kidneys to remove toxins and waste products from the body.
• Loss of concentration, confusion, seizures, or coma: If severe uremia develops, this may result in these neurological symptoms.

What causes chronic kidney disease?

Causes leading to chronic kidney disease may be inherited or acquired. Your overall health and lifestyle may determine the presence of additional risk factors. Common causes include:

• Diabetes: Diabetes, a disease that causes abnormally high blood sugar, is the most common cause of chronic kidney disease in most countries, constituting about 40 percent of cases overall. About 30 to 40 percent of people with diabetes will eventually develop chronic kidney disease. Diabetes causes chronic kidney disease by altering blood flow in the kidneys and causing damage and inflammation.
• Hypertension: Hypertension causes chronic kidney disease by damaging the blood vessels in the kidneys.
• Kidney infections: Repeated and/or long-term kidney infections (sometimes correlating to frequent kidney stones) can lead to the development of chronic kidney disease. These include certain bacterial infections as well as HIV, the virus that causes AIDS.
• Inflammatory diseases of the kidneys: These include lupus, sarcoidosis, and Sjogren's syndrome.
• Inherited kidney diseases: Certain inherited kidney diseases can lead to the development of chronic kidney disease. Check for a family history of kidney disease. A common example is a condition called polycystic kidney disease, in which multiple fluid-filled structures develop in the kidneys.

Other risk factors

Other specific risk factors for chronic kidney disease include the following.

• Obesity: Obesity, defined as a body mass index of 30 kg/m2 or greater, is a risk factor for developing chronic kidney disease. This may be due to the systemic inflammation caused by obesity.
• High blood pressure: Prolonged hypertension (high blood pressure) can lead to damage to the delicate arteries and capillaries of the kidney and lead to chronic kidney disease.
• Prolonged exposure to toxins or medications toxic to the kidneys: These include nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, antibiotics, chemotherapy agents, heavy metals, and irradiation. All cause problems for the sensitive kidney tissue.
• Being born prematurely or with low birthweight: This can occur because the kidneys are not completely developed at birth. These individuals often develop chronic kidney disease in adolescence.

Treatment options and prevention for chronic kidney disease

Chronic kidney disease is a chronic condition that cannot be cured. Treatment focuses on medications and lifestyle changes to slow the progression of the disease and to manage symptoms and complications. End-stage chronic kidney disease may require "renal replacement therapy," or therapy to replace the function of the kidneys. Renal replacement therapy includes various options for dialysis as well as a kidney transplant.

Dietary changes

Most adults with chronic kidney disease will benefit from dietary changes to prevent complications of chronic kidney disease. These include:

• Limiting sodium: This is salt intake, which in excess can cause volume overload.
• Limiting potassium intake: This is to avoid high potassium levels.
• Limiting phosphate intake: This is to prevent high phosphate levels and chronic kidney disease-associated bone disorders.

Medication for blood pressure and protein excretion

To slow the progression of kidney damage, it is usually beneficial to reduce blood pressure and protein excretion in the urine. Medications include lisinopril, valsartan, diltiazem (Cardizem) and verapamil.

When to seek further consultation for chronic kidney disease

If you have any conditions that can cause chronic kidney disease such as diabetes or hypertension you should see your physician. He or she can come up with a treatment plan to help you manage your chronic condition and reduce your risk of developing chronic kidney disease.

If you develop symptoms of chronic kidney disease

You should see your physician. He or she can order laboratory tests to determine if you have chronic kidney disease as well as the potential cause of your disease, and then come up with a treatment plan.

How is chronic kidney disease diagnosed?

Chronic kidney disease (CKD) is diagnosed through a combination of physical examinations, laboratory tests, and imaging studies. Here are some of the diagnostic procedures your doctor may use:

1. Physical examination: Doctors will conduct a physical examination to check for signs of kidney damage such as edema (swelling caused by water retention) and hypertension (high blood pressure)
2. Blood and urine tests: Blood tests and urine tests are used to measure kidney function, including the levels of creatinine and blood urea nitrogen (BUN), both of which are markers for the glomerular filtration rate (GFR). The GFR is an important measure of how much blood is flowing through your kidney's glomeruli - where the filtration occurs between the blood and the part of the kidneys that ultimately excrete urine. High levels of these substances may indicate kidney damage. Further, hyperkalemia (high levels of potassium) seen in your blood test may be a sign that not enough blood is filtering through your kidney. The kidney tightly regulates potassium (dysregulated potassium can lead to a quick death), so any changes are worrisome of kidney injury. Last, hyperphosphatemia (high levels of phosphate, above 4.5 mg/dL) can also be a sign of kidney damage.
3. Urine albumin test: This test measures the amount of albumin (a protein) in your urine. Detection of a small amount of albumin in your urine may be an early sign of kidney problems because albumin should not be able to pass through the filtering system of the kidneys. When your kidney is functioning normally, it never wastes protein in your urine.
4. Imaging studies: Your doctor may order imaging studies such as an ultrasound or a CT scan to visualize your kidneys and assess their size and structure to look for any abnormalities.
5. Kidney biopsy: In some cases, your doctor may recommend a kidney biopsy to confirm a diagnosis of CKD. During the biopsy, a small sample of kidney tissue is removed and analyzed in a laboratory.

Early detection and diagnosis of CKD are important to prevent or delay further kidney damage. If you suspect that you may have CKD or have been diagnosed with the condition, it's important to work closely with your healthcare provider to manage your kidney function and prevent complications.