Atrophic Kidney

An atrophic kidney is when your kidney is smaller than usual, which affects how well it works. Most people have two kidneys. Each kidney is about 4 to 5 inches (10 to 12 centimeters) long — about the size of your fist. But if you have an atrophic kidney, something affects it and causes it to shrink. An atrophic kidney is usually less than 3.5 to 4 inches (9 to 10 centimeters).

Causes may include a low blood supply to the kidney or a loss of nephrons. Nephrons filter your blood by reabsorbing certain substances and removing waste products and excess water.

This condition may affect one or both of your kidneys. If it affects one kidney, it’s a singular atrophic kidney. Having bilateral atrophic kidneys means both of your kidneys are smaller than usual.

Other names for an atrophic (pronounced “ay-TROF-ik”) kidney include:

• Kidney atrophy
• Renal atrophy
• Atrophied kidney

Types

Healthcare providers may classify it as:

• Congenital atrophic kidney: Your kidney is smaller than expected at birth.
• Acquired atrophic kidney: A condition or disease causes your kidney to get smaller.

Symptoms of atrophic kidney

You may not have any symptoms. But if you do, atrophic kidney symptoms may include:

• Abdominal pain
• Flank pain
• Pain while peeing (dysuria)
• Blood in your pee (hematuria)
• Frequent urination
• Fatigue
• Loss of appetite
• Muscle cramps
• Swelling, especially around your hands and feet
• Itchiness

Causes

Atrophic kidney causes include:

• Chronic kidney disease (CKD): As your kidneys slowly start to lose their function, they may develop scar tissue and shrink.
• Renal artery stenosis: A blockage affects the arteries that supply blood to your kidneys. Less blood flow can cause your kidneys to shrink.
• Obstructive uropathy: A blockage in your urinary system affects how well you can pee. Extra pressure can damage the nephrons.
• Kidney infections: Long-lasting kidney infections can eventually cause your kidneys to shrink.

Risk factors

You may have a greater chance of developing an atrophic kidney if you have:

• Diabetes
• Heart disease
• High blood pressure
• A history of kidney disease in your biological family

Complications

Complications depend on the cause and how much damage it creates. But they may include:

• High blood pressure
• Chronic kidney disease
• Kidney failure

If you have a unilateral atrophic kidney, you may not have any problems. If your other kidney is healthy, it’ll work harder to help make up the work of your atrophied kidney.

How doctors diagnose atrophic kidney

Your healthcare provider will:

• Review your medical history
• Ask about your symptoms
• Conduct a physical exam

If they suspect a problem with your kidneys, they’ll recommend:

• Imaging tests: An ultrasound, CT scan or MRI help your provider get a more detailed look at your kidneys and the surrounding areas.
• Blood tests: Your provider can examine a sample to see how well your kidneys filter your blood (estimated glomerular filtration rate or eGFR)
• Pee tests (urinalysis): Your provider can examine a sample to check for proteins and waste products in your pee. This lets them see how well your kidneys work.

How is atrophic kidney treated?

Treatment depends on its cause and whether it affects one or both kidneys. You can’t reverse renal atrophy. But your healthcare provider can help you manage it. They may recommend:

• Managing your blood glucose (sugar) and blood pressure
• Medications to help treat chronic kidney disease
• Medications to improve blood flow to your kidneys
• A procedure to treat a blockage in your renal artery
• Medications or a procedure to remove a blockage in your urinary system
• Antibiotics to treat a kidney infection

If you have two atrophic kidneys and they both fail, you need dialysis or a kidney transplant to survive.

Can kidney function be improved?

Not always. But you can help protect your kidneys by:

• Drinking plenty of water
• Eating lots of whole grains and fresh fruits and vegetables
• Cutting back on alcohol, salt (sodium), sugar and ultra-processed or fried foods
• Avoiding or quitting smoking
• Getting at least 30 minutes of physical activity most days
• Monitoring your blood pressure
• Limiting how many nonsteroidal anti-inflammatory drugs (NSAIDs) you take
• Scheduling regular checkups with a healthcare provider

When should I see my healthcare provider?

Schedule an appointment with your provider as soon as you notice symptoms of kidney atrophy. These include changes to your peeing habits, swelling and pain around your kidneys.

If you have only one kidney, it’s a good idea to have your provider check your kidney health at least once a year. Early detection of an atrophic kidney can help preserve kidney function.

What can I expect if I have an atrophic kidney?

If you have kidney atrophy, you can still live a long, healthy and active life. But it’s important to take extra care of your kidney(s) to ensure the best possible outcome. You must follow your treatment plan, including:

• Taking your medications as prescribed
• Eating kidney-friendly foods
• Monitoring your blood pressure and blood sugar levels
• Going to regular appointments with a nephrologist to monitor your kidney function

If you have a singular atrophic kidney and it stops functioning, your other kidney can still filter your blood. But if you have bilateral atrophic kidneys and they both stop functioning, you need dialysis or a kidney transplant.