What is Atrophic Kidney? When the Body Filters Begin to Fail

An atrophic kidney refers to a kidney that has shrunken smaller than its normal size. It is a weakened organ that can no longer filter blood as it should. It is a silent progression occurring in about 1 in 10 people with chronic kidney disease. When your kidneys fail, you lose your built-in water filter. As a result, it no longer functions (hence shrinks in size), and waste builds up in your body. It could lead to various conditions like increase in blood pressure and could manifest as easy fatigability (getting tired easily). Through time, the condition quietly disrupts the body’s balance of toxins and fluids. Early detection and intervention are two critical steps for your health.

Key Takeaways

• Atrophic kidney occurs in about 10% of chronic kidney disease (CKD) patients

• It occurs when kidneys shrink smaller than its usual size due to the loss of nephrons (the body’s filtering units)

• Common causes of kidney atrophy include diabetes (occurring in about 40% of cases), obstruction in the urinary tract (occurring in about 10% of cases), and chronic (or recurrent) infections that can damage the kidneys over time

• Early symptoms include blood in urine, flank (side) pain, and fatigue although some patients may remain asymptomatic until it advances

• Diagnosis relies on ultrasound imaging with 90% accuracy and blood tests for kidney function like eGFR (estimated glomerular filtration rate) and creatinine

• Treatment focuses on the management of underlying conditions rather than aiming at the reversal of atrophy

• Complications could include progression to kidney failure and high blood pressure

• Most patients with a single functional kidney can maintain stable function for years with proper treatment

• Dietary modifications like reducing salt intake can benefit patients

What Causes an Atrophic Kidney?

There are several different causes for kidney atrophy. The most common cause being chronic kidney disease (CKD). This condition goes on to damage your kidneys for months and years, which affects millions of Americans.

Obstruction in your urinary system can cause 10% of atrophic kidney cases. The obstruction does not allow your urine to flow freely, it backs up, and creates pressure that can damage the kidneys in the process.

Kidney infections also lead to atrophy, especially the repeated or recurrent ones. When bacteria attacks your kidney repeatedly or when it is severe yet left untreated, the inflammation and scarring can damage your kidneys.

What Underlying Conditions Lead to Kidney Atrophy?

Diabetes can cause the majority of CKD cases. When you have persistent high sugar levels in the blood, it damages the small blood vessels in your kidneys over time. The damage often occurs slowly, progressively, and often showing no symptoms. The only time that it will show symptoms is when the damage has already been significant. Progression to end-stage CKD takes years and is often silent.

Glomerulonephritis is an inflammation (swelling) of the filtering units of the kidneys. When these structures are swollen for a long time, the scar tissue can form and replace the healthy cells. This condition can also progress to an atrophic kidney if not treated properly.

Chronic kidney infections can cause prolonged inflammation that leads to damage and eventually scarring of the kidney tissue. Unlike isolated infections that come and go, chronic infections can persist and continuously attack the tissues of your kidney. This continuous attack leads to permanent damage and ultimately shrinkage of the kidney size.

Autoimmune diseases like lupus can attack kidney tissues as well. Your immune system will mistake your kidney tissues as foreign and invade them in the process. The result of this attack could be inflammation and damage that may lead to atrophy over time.

How do obstructions cause kidney shrinkage?

Urinary obstructions cause restriction of urine flow. When urine can’t flow normally as it should from the kidneys to the bladder, pressure will build up inside the kidney. The increase in pressure will progressively damage the kidneys, particularly the filtering units. Consequently, blood flow to the kidney will be reduced as well.

The majority of the urinary obstructions cases are kidney stones. These are hard deposits that get stuck in the ureter (the tube that carries urine from the kidneys to the bladder). Untreated, this will eventually lead to atrophic kidney.

Tumors can also press on your urinary tracks and can create obstructions. These growths can press on the ureter, reduce flow of the urine, and create pressure that damages kidney tissue.

In men, enlargement of the prostate can also block urine flow. When it grows large enough to squeeze the urethra, urine cannot be eliminated so it backs up to the urinary system. The urine will eventually reach the kidneys, which will create pressure eventually leading to atrophy.

The longer the obstruction stays, the more likely that permanent damage will occur to your kidneys. Early detection and treatment of the obstruction can often prevent or minimize kidney damage.

What Are the Symptoms of an Atrophic Kidney?

Understanding the symptoms of an atrophic kidney because the condition typically develops slowly over the years. Your body has an amazing ability to compensate even when only one kidney is left functioning. The other kidney has to double the work in order to maintain the function. This compensation masks the symptoms of the diseased kidney  until it becomes more serious.

• Pain — dull, achy, and located at the flank (side), region under the ribs and hip on affected side

• Blood in urine (hematuria) — may be visible (urine appears pink, red tinge, or brown) or can only be seen under the microscope)

• Changes in urination pattern — may increase as remaining healthy kidney compensates

• Fatigue and weakness — appears as condition progresses; caused by toxin buildup due to ineffective waste filtration; deep-seated exhaustion not relieved by ample rest

• Swelling — around the eyes, ankles, and legs due to fluid retention; develops slowly and more noticeable after prolonged standing or walking

The changes may seem trivial at first and hardly noticeable but becomes more obvious as the condition progresses or turns for the worst.

How does kidney atrophy affect daily life?

Living with kidney atrophy can impact the various aspects of your daily life. The severity may vary from person to person.

You may note that fatigue is one of the symptoms that challenges them during your day. Regardless of your activity and performance, it will make you feel drained and with decreased energy.

This is compounded by the fact that your need to have dietary restrictions. It is a necessity particularly when the kidney function is starting to decline. You may need to limit the amount of intake for the following:

• Salt (sodium)

• Protein

• Phosphorus

This makes meal planning even more difficult than it already is. Social dining becomes challenging, so you may tend to abstain from social gathering. However, you can take this as a positive means to learn new skills like cooking and reading product labels as a habit.

A reduced quality of life can, indeed, be experienced by people who have kidney atrophy. But with proper lifestyle management and changes, you can maintain productive and satisfying lives. 

You may also experience disturbance in their sleep patterns. This is because of frequent nighttime urination or discomfort from fluid retention. It is just a matter of adjusting how you drink fluids so as to minimize your sleep interruption at night. Yet, keep your hydration status.

There may be a need to adjust some physical and work changes, as well. This is especially true if the fatigue becomes more significant. You could benefit from proper pacing strategies so you could save as much energy as you can for more important events while avoiding overexertion that may worsen your symptoms.

When should you see a kidney doctor?

You should always keep your nephrologist (kidney doctor) in the loop. Consult immediately if you see or experience the following:

• Blood in your urine (hematuria)

• Persistent flank (side) pain that is not relieved by over-the-counter pain meds

• Fever

• Nausea

• Urination pattern changes

Left untreated, kidney atrophy could progress drastically to kidney failure. This means that you need to aim at early intervention and treatment. Early intervention would give you more chances at preserving the remaining kidney function. You don’t need to wait until the symptoms get worse.

Any unusual symptom at all or a new onset at that should be checked and evaluated by your doctor. Don’t let your kidneys struggle too much and allow your doctor to perform what needs to be done to keep your kidneys working.

How Is an Atrophic Kidney Diagnosed?

To diagnose an atrophic kidney, it requires a comprehensive approach. It must combine available and accessible resources, such as clinic evaluation and technology like imaging and laboratory testing.

The diagnostic process requires careful consideration of the results, both in clinical and technical aspects. Creating a complete picture of kidney function and health is not an easy task, which requires medical knowledge.

Modern technology has paved the way to detect kidney atrophy much earlier than in the past. This early detection is very important because it may be the way for you to get early treatment so the condition may prevent or slow down the progression of the kidney damage.

To obtain the correct diagnosis, you need to go through the following:

• Medical history evaluation

• Physical assessment

• Imaging tests

• Blood work

• Urine tests

Often, the diagnosis requires multiple sets of testing to know exactly the extent of damage. There are several factors that affect kidney function so a single test would rarely make the definitive diagnosis.

What imaging tests detect kidney atrophy?

The common imaging tests to detect kidney atrophy include:

• Ultrasound

• CT (computed tomography) scan

• MRI (magnetic resonance imaging)

• Nuclear medicine studies

These are the imaging techniques used to see the status of your kidney and diagnose whether it has progressed to atrophy.

Which blood tests are used?

Some of the blood tests that are used to get a picture of your kidney’s function, include:

• Creatinine level in the blood serves as a marker for kidney function. It is a waste product that is normally filtered out by the kidneys. So accumulation of creatinine in the blood reflected by the high creatinine levels means there is a decline in kidney function.

• Glomerular filtration rate (GFR) provides a more precise evaluation of the kidney than creatinine levels alone. The GFR can estimate how much blood is filtered by your kidneys each minute. A normal GFR has a result of 60 or higher, while below this number generally means there is significant decline of function due to damage, which increases your risk of complications.

• Blood urea nitrogen (BUN) test also measures the amount of another waste product that healthy kidneys usually filter out. High BUN levels with high results of creatinine suggest that the kidneys are not functioning as they should.

• Electrolyte panel is another blood test that you may encounter in diagnosing atrophic kidneys. The laboratory will check on the levels of the following electrolytes, which are necessary function of the kidneys (to keep the balance between these electrolytes):

• Sodium

• Potassium

• Phosphorus

• Calcium

• Magnesium

• Complete blood counts (CBC) is requested to see if there’s anemia, which is also a common sign of kidney disease. The kidney is actively involved in the production of erythropoietin (hormone), which is essential for creating red blood cells (RBCs). So derangement in kidney function could lead to lower RBC.

These are just some of laboratory tests used to evaluate kidney function.

Can an Atrophic Kidney Be Treated or Reversed?

The treatment for atrophic kidney focuses on the underlying issue or causes. The aim is to prevent further damage rather than reversing the atrophy itself.

Can lifestyle changes help?

Yes, some of the ways to prevent further kidney damage is to make modifications to your lifestyle. Some of which includes:

• Eating right

• Limit salt intake

• Ensure proper hydration

• Avoid too much protein

• Regular physical activity

With the right lifestyle changes, you can prevent further damage to your kidneys, which leads us to what medications can help.

What medical treatments are available?

Medications targeting underlying conditions represent the cornerstone of medical treatment for atrophic kidney.

• Antibiotics (for those caused by infections)

• ACE inhibitors and ARB medications (for protection of the remaining functional kidneys)

• Medications that treat underlying conditions

• Antihypertensives

• Antidiabetics

• Supportive medicines

• Treatment of mineral and bone disorders

• Folate or iron for anemia

In severe cases, dialysis and surgery (particularly transplantation) may be necessary. If you already have chronic kidney disease, your chances of dialysis increases. This is the reason why early intervention is important.

What Are the Complications of Atrophic Kidney?

The complications of atrophic kidney primarily depend on whether it is unilateral (one kidney only) or bilateral (both kidneys). It includes the following:

• Chronic kidney disease 

• Kidney failure

• High blood pressure

• Heart disease risk

• Fluid retention

• Edema of the lung

• Anemia

If the condition only involves one kidney, it may produce little or no complications at all especially if caught early. However, with the involvement of two kidneys, kidney failure is more likely to happen. This gives value to early diagnosis so your healthcare provider can make an appropriate management plan for you.

What is the Long-Term Outlook for Atrophic Kidney?

The long-term outlook for patients with an atrophic kidney depends on:

• Underlying causes

• How severe the atrophy is

• Function of the remaining kidney tissue

You can live a long, healthy, and productive life even with one kidney. But that is on the premise that you are following doctor’s orders and have regular follow-up.

Like mentioned, some cases may lead to chronic kidney disease. This happens when the functioning of your kidney goes less than 25%.

If you have been on dialysis, the average survival rate is about 5-10 years. But with the right treatment approach you can live longer than this.

On the average, post-transplant survival sits at about 12 to 20 years. But these all depend on your overall health, how you take care of yourself, and the management plan you are following.

How to Monitor Your Condition?

Apart from the regular checkup that you need to follow, laboratory tests and periodic imaging may be necessary. Some of the tests are requested specifically by your doctor. However, there are also ways that you can be proactive, such as:

• Monitoring your blood pressure at home

• Practice healthy lifestyle (diet and exercise)

• Keep a symptom journal

• Monitor your weight

Why monitor your blood pressure at home? It was shown that having a high blood pressure that goes beyond 180 mmHg, increases the two-year risk of kidney shrinkage at about 35%.

There are also laboratory strips you can use to monitor your urine. Ribbon Checkup offers kits that would allow you to test your urine for urinary tract infection, presence of glucose, and it even allows protein testing. You might want to check out this method to be proactive at your kidney health.

Frequently Asked Questions

Can an atrophic kidney return to normal size?

No. Unfortunately, once the kidney has atrophied and the filtering units are gone, the kidney cannot return to its original size. However, the remaining healthy kidney tissue can compensate for what was lost.

Is it possible to live normally with one atrophic kidney?

Yes, it is still possible to live normally even with one atrophic kidney. The reason is because the other kidney can double its function in filtering blood so that the body can adapt to the chances.

What foods should I avoid with an atrophic kidney?

You should avoid foods that are rich in sodium (salt), which can be found in processed foods, canned goods, and even restaurant meals.

 

Written by Jaclyn P. Leyson-Azuela, RMT, MD, MPH
Jaclyn P. Leyson-Azuela, RMT, MD, MPH, is a licensed General Practitioner and Public Health Expert. She currently serves as a physician in private practice, combining clinical care with her passion for preventive health and community wellness.

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