Kidney Atrophy

Kidney atrophy (also called atrophic kidney or renal atrophy) means that the kidney is smaller than average. Kidneys are usually about the size of a fist or 10 to 12 cm (about 5 inches). Kidney atrophy can be singular (one kidney) or bilateral (both kidneys).

Kidney atrophy can be due to a lower blood supply to the kidney(s) and/or loss of nephrons, the basic working units of the kidneys. Chronic infections or blockage of the kidney can also result in kidney atrophy. A person with kidney hypoplasia (also called renal hypoplasia) is born with a smaller kidney.

Sometimes kidney atrophy can have no symptoms, especially if the cause is slow and over many years.

Some symptoms of kidney atrophy can include:

• Pain while passing urine
• Pain in the abdomen (belly) or flank (side and back)
• Blood in urine
• Urinating more often
• Feeling tired (fatigue)
• Loss of appetite
• Itchy skin
• General discomfort in the kidney area
• Muscle cramps
• Swelling of the hands and feet

Kidney atrophy may be due to:

• Blocked kidney artery (known as renal artery stenosis): Blocks the main arteries that supply blood to the kidneys, which can be due to hardening of the arteries with fatty deposits or blood clots
• Blocked urinary tract: Blocks the normal flow of urine which leads to pressure on the kidneys and damages the nephrons
• Kidney stones: An untreated kidney stone can cause a kidney blockage
• Long-lasting kidney infections (pyelonephritis): An infection in the kidneys. Usually caused by bacteria. It starts as a bladder or urinary tract infection and moves to the kidney
• Autoimmune diseases of the kidney: A chronic condition where the immune system attacks the kidney

If kidney atrophy involves one kidney (unilateral) and the other kidney is not impacted then there may be few or no health problems. However, if both kidneys are impacted (bilateral) then kidney atrophy can lead to chronic kidney disease.

Chronic kidney disease can eventually lead to kidney failure. People with kidney failure will need dialysis or a kidney transplant to survive.

Tests

Tests for kidney atrophy include imaging tests such as ultrasound, computed tomography (CT or CAT) scan, or magnetic resonance imaging (MRI). A CT scan uses x-rays to get many detailed pictures of the kidneys or other parts of the body. An MRI uses strong magnets and radio waves to get many detailed pictures of the kidneys or other parts of the body. Early diagnosis and treatment of kidney atrophy is important to avoid further kidney damage.

Your healthcare professional will also check your kidney function by giving you a simple urine test and a simple blood test. Estimated glomerular filtration rate (eGFR) is a blood test that checks how well the kidneys are filtering your blood. A urinary albumin-to-creatinine ratio (uACR) is a urine test that checks for high protein (albumin) in the urine, which is a sign of kidney damage.

Overview

The treatment for kidney atrophy depends on what caused the kidney to become smaller in the first place. For example, a patient with kidney atrophy due to chronic urinary tract infection would need antibiotics.

Your healthcare professional will find out how much kidney function is left through blood and urine tests. If the kidney is not working at all, and the other kidney is fully functioning, then kidney removal is not usually required unless there is an ongoing problem such as repeated infection.

If the kidney is still filtering or working, there may be medical treatment to keep the kidney function that’s left (medicines and nutrition). If both kidneys are impacted and end up in kidney failure, then the treatment is dialysis or kidney transplant. Think about kidney health by controlling your blood pressure, not smoking, treating your diabetes if you have it, keeping a healthy weight, and eating a low salt healthy diet. It is also important to follow up with your healthcare professional for regular check-ups.

Medications

If needed, your healthcare professional may prescribe one or more medicines to help slow down your kidney disease. These medicines can include an ACE inhibitor/ARB, diuretic (water pill), an SGLT2 inhibitor and/or an nsMRA.

Nutrition

Nutrition and eating well are important parts of your health. Eating well, or eating healthy, generally includes having more fruits and vegetables, and eating foods that are less processed and as close to fresh as possible. You might need to change your diet. For example, you may need to limit your sodium (salt) intake, especially if you have high blood pressure. A dietitian can help with a meal plan that’s right for you.

Questions to ask

• Did I receive eGFR and uACR test? If so, what are the results?
• Am I at a healthy weight?
• Is my blood pressure within the recommended goal range?
• Are there any changes I should make to my diet?
• Is there anything I can do to maintain my overall health and kidney health?

This content is provided for informational use only and is not intended as medical advice or as a substitute for the medical advice of a healthcare professional.