Atrophic Kidney: Symptoms, Causes, Diagnosis, And Treatment

Atrophic kidney, also known as renal atrophy, refers to a condition in which one or both kidneys shrink to a smaller size, thus hindering normal function.

Kidney atrophy should not be confused with renal hypoplasia, where the person is born with kidneys that are smaller than normal. Instead, kidney atrophy occurs due to shrinkage of what were once normal-sized kidneys.

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Symptoms of atrophic kidney

You may not exhibit symptoms immediately when you have this condition. But you may notice the following symptoms as the disease progresses.

  • More frequent urination

  • Sleepiness

  • Muscle cramps

  • Loss of appetite

  • Itchy skin

  • Swelling of the hands and feet

  • Abdominal pain

Causes of atrophic kidney

The kidney can shrink as a result of the following reasons:

  • A blocked urinary tract leads to pressure on the kidneys and damages the nephrons

  • Untreated kidney stones 

  • Other long-lasting kidney infections like pyelonephritis and reflux nephropathy

  • Narrowing of the artery supplying the kidney with blood

  • Renal artery occlusion due to a blood clot that blocks the artery that supplies the kidney with oxygenated blood

  • Chronic autoimmune conditions of the kidney 

How doctors diagnose atrophic kidney

A doctor can diagnose whether you have renal atrophy by having tests done. Generally, healthcare providers use blood tests such as glomerular filtration rate (GFR)¹ to check kidney function. The doctor may also conduct a urine test for albumin, a protein that can show up in the urine when the kidney is damaged. 

Once these tests establish an issue with the kidney, the doctor can further image your kidney structures through an ultrasound and computed tomography scan² to determine whether you have kidney atrophy.

Blood test for GFR

You are likely to present any of the following results after undergoing a blood test:

  • A GFR of 60 or more generally indicates that you are in the normal range

  • A GFR of less than 60 may mean that you have kidney disease

  • A GFR reading of 15 or lower likely indicates that you have kidney failure 

If you have a GFR of less than 60, your doctor will probably order more tests. However, with a GFR of 15 or lower, you will already need regular dialysis or a kidney transplant.

The doctor estimates your GFR by measuring the creatinine levels in your blood. Creatinine is a waste product resulting from the normal breakdown of muscles in the body. Kidneys usually remove this from your blood. However, creatinine levels in the blood rise as kidney disease worsens.

Urine test for albumin

Albumin is a protein present in the blood. If your kidneys are healthy, they will not allow the albumin to pass into the urine, while a damaged kidney will. More blood albumin would mean the kidneys are not in good condition.

The doctor may test for albumin in your urine using any of these ways:

Dipstick test

The doctor places a chemically treated paper called a dipstick into the urine sample you provide. The dipstick changes color if there is albumin in the urine.

Urine albumin-to-creatinine ratio

This test compares the albumin and creatinine amounts in the urine. If you present a urine albumin result of 30 mg/g or less, it is normal. Anything more than that may be a sign of kidney disease.

These tests can also help the doctor determine whether the treatment interventions are working. However, the above tests are not conclusive of kidney atrophy, and the doctor would need to image the kidneys to ascertain whether they are smaller than they should be.

Ultrasound

Ultrasound uses sound waves to develop an image of your internal organs to understand processes or diagnose medical conditions.

A renal ultrasound focuses on the areas around your kidney and bladder. The process is painless and does not use radiation, as is the case with X-rays. You may need to observe the following while preparing for a kidney ultrasound.

  • Drink about a quarter of a gallon of water to obtain better image

  • Steer clear of fat before the test

  • Limit or avoid food

You should consult your doctor to determine what you should do before the test to ensure you get the best results. 

You will be asked to lie on a padded exam table for the test. The doctor will apply an ultrasound gel to your abdomen and move the transducer around the area between the hip bones and below the belly button to take images of your kidneys and bladder. To get a clear picture, your doctor may ask you to roll on your side or your back.

The gel acts as a connector between the transducer and the skin by eliminating the air pockets held by the tiny hairs, thus enabling the ultrasound waves to travel directly to the tissues between the skin.

The healthcare professional may request you to change positions or hold your breath to capture the images better.

You will be done with the whole test within 20 to 30 minutes and expect the results within 24 hours. The doctor will discuss the test results and help you establish whether you have atrophic kidneys.

Computerized tomography (CT) scan

The doctor may also conduct a computerized tomography (CT) urogram, a scan that images the urinary tract, which encompasses the kidneys, bladder, and ureters. The CT scan utilizes X-rays to create images of the area under observation. 

Before the scan, the doctor injects iodine contrast material into a vein in your arm, which then flows to the kidneys and outlines the structures under study.

In addition to diagnosing renal atrophy, the CT scan can also help diagnose conditions such as:

  • Cancer

  • Bladder stones

  • Tumors and cysts

  • Structural problems

  • Kidney stones

A CT scan may provoke a slight allergic reaction to the injected contrast material. However, the reaction symptoms are mild, and you can relieve them with medicine. Some symptoms of the allergic reaction include:

  • Nausea

  • Itching

  • Hives

The radiation in a single CT scan is mild and does not cause cancer, but multiple tests can slightly increase this risk. However, the risks are minimal relative to the benefits of an accurate diagnosis.

It would help if you revealed the following details before the scan.

  • If you have allergies to iodine

  • If you are pregnant or suspect that you are 

  • If you have had a severe reaction to X-ray dyes

  • If you have medical conditions such as heart disease, asthma, diabetes, thyroid disorders, or kidney disease

Doctors will also do the following before beginning the test:

  • Ask about your medical history

  • Examine your pulse, body temperature, and blood pressure

The doctor will ask you to lie on your back or side during the CT scan. Your positions may change throughout the process. They will then intravenously deliver the X-ray dye into your body, which may induce a warm, flushed feeling and a metallic taste in your mouth. 

You will be moved through the machine, which will take the pictures. Afterward, the attendant will remove the IV line from your arm and dress the entry point.

A radiologist is normally charged with reading and interpreting the image results and sending the report to your healthcare professional, who will then discuss the results with you.

Management of atrophic kidney

Atrophic kidneys may not work at optimum capacity, so it is important to know what you can do to ease the burden on your kidneys if you are diagnosed with this condition.

Limit your protein intake

The more proteins you take, the harder your kidneys have to work to eliminate the resulting waste. Therefore, you should limit your intake of proteins and instead go for foods that produce fewer waste products.

Some of these proteins include lean meats, fish, and egg whites. Therefore, you should be mindful of the portions you consume by keeping them to a minimum.

For instance, a slice of fish, 2 to 3 ounces of meat, and half a cup of beans, grains, or nuts are some of the portions you should consider consuming at a time to meet your protein requirements without burdening your kidney.

Lower your sodium consumption

A high sodium intake alters the sodium balance, causing the body to retain fluid. Too much fluid can result in high blood pressure, straining your kidneys. Therefore, lowering your intake of sodium-rich foods will save your kidneys from this strain. 

Some of the strategies you could use include:

  • Consume fresh foods instead of packaged or processed ones where possible

  • Check the sodium content on food labels

  • Minimize salt in foods or choose other seasonings 

  • Rinse canned food before cooking or serving

  • Instead of eating out at restaurants and fast-food joints, cook at home as you can then control the ingredients

Choose foods with low phosphorus

Kidney diseases such as atrophic kidney can result in a phosphorus build-up in your blood. It is thus advisable to consume food that has lower phosphoric content. 

Some of the foods to include in your diet include:

  • Bread, pasta, and rice

  • Fresh fruits and vegetables

  • Rice and corn-based cereal

Read food labels to know the level of phosphorus content in packaged foods.

Minimize potassium intake

It is prudent to reduce the amount of potassium you consume if you have renal atrophy, as poorly performing kidneys will not be able to balance these minerals, leading to the accumulation of potassium in the blood. 

Foods with low potassium content include:

  • Carrots and green beans

  • Apples

  • Pasta, white rice, and bread

You should avoid foods with high potassium, such as:

  • Oranges

  • Bananas

  • Beans

  • Nuts

  • Dairy foods

  • Potatoes and tomatoes

  • Dried fruits

  • Beef

  • Pork

  • Stone fruit (peaches, plums, avocado)

Treatment for atrophic kidney

Doctors cannot reverse renal atrophy, but they can treat the atrophic kidney’s underlying cause, thus preventing further damage. Knowing the exact cause of the kidney atrophy will help determine the treatment option available. For instance, atrophy resulting from chronic urinary tract infections (UTI) can be tamed by taking antibiotics.

Controlling your blood pressure and conditions such as diabetes will also keep your other kidney functional and free from atrophy if only one has been affected.

If both kidneys have lost their functionality due to the atrophy, then dialysis sessions where the blood is run through a hemodialyzer to remove the waste products will assist with kidney functions. However, dialysis is not a cure and can prove hectic as you would require multiple weekly sessions for the rest of your life.

The more viable alternative would be to get a kidney transplant from a living or deceased donor. In such a case, you will have to take antirejection medication for the period that you have the kidney.

A kidney transplant from a live donor can last you as long as 20 years, while that from a deceased donor may last you up to 12 years. However, these are not absolute numbers, as other factors like age and health conditions also come into play. Your doctor is thus the best person to ask about your situation.

A kidney transplant is only necessary if you have no functioning kidney, as you can live a normal, healthy life with a single functioning kidney. In fact, when you have a kidney transplant, you only get one of the donor’s kidneys, not two.

You would, however, need to take certain precautions to protect your remaining kidney from injury. One precaution is to avoid contact sports such as wrestling, football, soccer, rugby, and hockey, as engaging in them could result in a knock, injuring your kidney. While protective gear and padding may minimize the likelihood of injury, this is not a full-proof strategy.

Being careful when riding a motorcycle, rock climbing, and participating in extreme sports such as skydiving and bungee jumping can also keep your kidney safe from harm.

If you have to drink, do so in moderation because kidney failure is likely to occur more rapidly when functioning on a single kidney.

Can atrophic kidneys be prevented?

While there are no guarantees that you can prevent the disease, you could keep your kidneys in good working condition by preventing or managing conditions such as high blood pressure or diabetes, as these can damage your kidneys. 

Keeping off foods with high sodium or sugar, alcohol, and highly processed foods can also go a long way in managing the disease.

Observing a healthy weight, exercising regularly, and managing your cholesterol levels are actions you can take to live healthily despite the disease.

Complications of atrophic kidney

If left to persist and affect both kidneys, the atrophy can result in kidney failure, where both of your kidneys cannot perform their function anymore. The sudden rise in potassium levels due to the inability of kidneys to filter the blood could impair your heart’s functioning and prove lethal. 

Chronic kidney failure from renal atrophy can also lead to fluid retention in your lungs, a condition known as pulmonary edema.³ At the same time, you may also experience lower sex drive, erectile dysfunction, and reduced fertility. Anemia is also another condition that you could develop.

When to visit a doctor

Visit your doctor if you manifest symptoms of kidney atrophy. The doctor will then conduct tests or image your kidneys to make a diagnosis. They will examine you regularly if they find out that you suffer from the disease. Blood and urine tests can help monitor the effectiveness of the treatment.

If you currently live on one kidney, you should visit your doctor at least once a year for evaluation and more often if there are complications. The doctor will measure the GFR and your blood pressure because higher blood pressure could be a marker for kidney dysfunction.

The lowdown

Atrophic kidney refers to a condition in which your once normal kidney(s) shrink and ultimately lose their functionality if the condition is not addressed immediately. If you have this condition, you may experience the need to urinate frequently, have swollen feet and arms, muscle cramps, loss of appetite, and may feel drowsy more often. 

The atrophic kidney is typically a consequence of illnesses that restrict the supply of blood to the kidney, resulting in the shrinking of the kidney structures such as nephrons. Doctors can conclusively diagnose the condition by conducting imaging exams such as ultrasound and CT scans. 

Blood and urine tests can also point out problems with your kidney by indicating the level of creatinine and albumin, respectively. While they are not conclusive in diagnosing renal atrophy, they can help monitor your response to treatment.

While renal atrophy is not reversible, it can be managed through proper dietary habits. You can also seek treatment for conditions that place you at risk of developing the condition. If both of your kidneys lose their functionality, dialysis, and kidney transplants are needed to ensure survival. 

You may not completely prevent the disease, but watching what you consume and visiting your doctor when you experience symptoms can help stop renal atrophy before it gets worse.

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