The kidneys are essential organs in the body that are needed for survival. Most people are born with two bean-shaped kidneys. These organs are part of the urinary tract that is responsible for creating and removing urine from the body.
Sometimes, after birth, one or both kidneys may not develop properly, resulting in them being smaller than usual. Chronic infections, acute injury, inflammatory disease, or other conditions may also cause damage to the kidneys, reducing their size.
This article discusses the causes, treatment, diagnosis, and management of kidney atrophy.
Key Points
- Kidney atrophy refers to the shrinking of the kidney that may be caused by a number of conditions.
- Kidney atrophy is irreversible; thus, treatment aims to preserve the remaining kidney function.
What is Kidney Atrophy?
The kidneys are found on each side of the spine, just under the ribcage. The left kidney may be a little larger than the right. In a healthy person, the kidneys usually are about 4 to 5 inches (10 to 12 cm) or the size of a fist.
Kidney atrophy refers to the shrinking of the kidney to an abnormal size. Kidney atrophy can occur in just one kidney or can affect both kidneys. The left kidney is thought to be more affected.
Kidney atrophy can occur for two reasons:
- A congenital problem: part of the kidney does not develop properly from birth, resulting in a small kidney. This type of kidney atrophy or small kidney generally does not require specialized treatment. This cause of kidney atrophy is not to be confused with renal hypoplasia, a condition where part of the kidney does not fully develop in the womb.
- Disease: This atrophy happens after birth and can occur in one or both kidneys. This type of kidney atrophy is due to reduced blood supply to the kidney(s) or the loss of nephrons (filtering units). Persistent (chronic) infections or blockages in the kidneys can also cause kidney atrophy.
A kidney that is atrophied can lead to chronic kidney disease, which means there is lasting damage that can get worse over time, leading to kidney failure.
Causes of Kidney Atrophy
Kidney atrophy can be caused by numerous conditions and diseases, such as:
- Renal artery stenosis (blocked kidney artery): This is the narrowing of one or more of the arteries, reducing blood flow into the kidneys. Reduced blood flow may cause injury to the kidney tissue and increase blood pressure in the body. The arteries can be hardened due to blood clots or fatty deposits.
- Kidney stones: kidney stones can cause a kidney blockage if left untreated.
- Ureteral obstruction (blocked urinary tract): This is a blockage in one or both of the ureters. This results in the normal flow of urine being blocked, forcing the urine to back up the ureters and damaging the kidneys. There are many different diseases and conditions that can cause a blockage of the ureters.
- Long-lasting kidney infections such as polycystic kidney disease, pyelonephritis, and other chronic kidney diseases can damage the nephrons.
Those at risk of developing kidney atrophy:
- Diabetes
- Hypertension (high blood pressure)
- Heart disease
- Genetics – a family history of kidney disease
Signs and Symptoms of Kidney Atrophy
The kidneys are responsible for filtering the blood in the body removing any waste products, toxins, and excess water. The kidneys also have a key role in controlling blood pressure, making red blood cells, regulating electrolyte levels, maintaining healthy bones, and helping maintain vitamin D levels.
When the kidney(s) become atrophied and are not able to work as they should, the following symptoms may present:
- Pain while passing urine
- Pain in the abdomen, side or back
- Blood in the urine
- Loss of appetite
- Itchy skin
- Fatigue (feeling tired)
- Muscle cramps
- Discomfort in the kidney area
- Swelling of the feet and hands
- Anemia
Sometimes, those with kidney atrophy may not have any symptoms, especially if the underlying causes are slow and develop over many years.
How is Kidney Atrophy Diagnosed?
Early diagnosis and treatment of kidney atrophy are essential to reduce any further kidney damage.
Tests for kidney atrophy include:
- Imaging tests such as MRI, CT scans, or an ultrasound: these tests can show the shape and size of the kidneys if there are any kidney stones or any signs of damage or injury to the kidneys. Imaging tests also provide a clear picture of the blood flow to the kidneys.
- Glomerular filtration rate (GFR): a blood test to measure how well the kidneys are functioning.
- A urine test: to check for signs of kidney disease or other health problems such as a urinary tract infection or kidney infection. Urine tests can also be used to check for complications of kidney atrophy, such as anemia and metabolic acidosis.
- Kidney biopsy: which may be suggested if the cause of kidney damage is unclear or if the kidney atrophy is caused by inflammatory kidney disease.
Treatment for Kidney Atrophy
Treatment for kidney atrophy will depend on the cause of the kidney becoming smaller. For example, if a patient has kidney atrophy caused by a chronic urinary tract infection, they would be prescribed antibiotics to treat the infection.
Kidney atrophy can be bilateral (both kidneys) or singular (one kidney). A physician or nephrologist will determine how much kidney function is left through urine or blood tests. Removal of the kidney that is not functioning at all is not typically removed unless there are repeated infections.
In the event that both kidneys fail, treatment options include dialysis or a kidney transplant. Treating and managing the underlying condition may help reduce or prevent further damage to the kidney(s).
Can Kidney Atrophy be Prevented?
Once a kidney has atrophied, there is nothing that can be done to return it to its normal size. However, there are some measures that can be implemented to help reduce or prevent further damage to the kidneys.
To manage kidney health, it is essential to control or prevent high blood pressure and diabetes, which are both causes of kidney disease. Some lifestyle changes that can be implemented include:
- Reduce or stop smoking or using chewing tobacco.
- Maintain a healthy weight.
- Work with your doctor and take medication as prescribed.
- Try to maintain regular sleep patterns (7 to 8 hours a night)
- Follow a healthy eating plan that is low in sodium, sugar, and fat.
- Limit alcohol use.
- Be active; set a goal to exercise for at least 30 minutes a day.
It is essential to keep follow-up appointments with nephrologists or physicians to monitor kidney health and ensure that treatment is effective. Talk to your doctor or nephrologist before changing exercise plans or eating plans.
Panoramic Health
Panoramic Health delivers better outcomes for patients at a lower cost through a physician-led, integrated, value-based kidney care platform. Kidney disease patients receive holistic care coordination that provides comprehensive and full-spectrum care.
