Atrophic Kidney

Overview

An atrophic kidney is a kidney that has become smaller than normal because of long-term damage, reduced blood flow, or loss of working tissue. As it shrinks, it often cannot filter waste from the blood as well as a healthy kidney. It is not a disease by itself, but a sign that the kidney has been affected by another condition. Many people with an atrophic kidney have no symptoms and the other kidney can do all the work.

It is not rare, especially among people with chronic kidney disease or high blood pressure. Many cases are mild and never cause noticeable symptoms.

It can affect anyone, but it is more common in older adults and in people with diabetes, high blood pressure, a history of kidney infections, kidney stones, or autoimmune conditions. Sometimes it is present from birth or runs in families.

Symptoms

Common symptoms

• No symptoms at all, especially if only one kidney is affected
• High blood pressure that is hard to control
• Swelling in the legs, ankles, or feet
• More frequent urination, especially at night
• Frothy or foamy urine
• Feeling tired or weak

Symptoms in children

• Poor growth or delayed development
• Frequent or severe kidney infections
• High blood pressure
• Swelling in the face, hands, or feet

Symptoms in older adults

• Loss of appetite
• Confusion or trouble concentrating
• Less urine than usual
• Weakness or dizziness
• Swelling in the legs or feet

Causes

Main causes

• Reduced blood flow to the kidney, often from narrowed kidney arteries
• Chronic glomerulonephritis, a condition that damages the kidney's tiny filters
• Repeated or long-lasting kidney infections (pyelonephritis)
• Kidney stones or other blockages that cause pressure and damage
• Reflux nephropathy, which is when urine flows backward into the kidneys
• Polycystic kidney disease or other inherited kidney conditions
• Injury or trauma to the kidney area

Risk factors

• High blood pressure
• Diabetes
• Smoking
• Obesity
• Older age
• A family history of kidney disease
• Autoimmune diseases, such as lupus
• Recurring urinary tract infections or kidney stones

When to see a doctor

See a doctor urgently if:

• If you have a sudden change in how much urine you pass, notice blood in your urine, or have severe pain in your back or side, seek care promptly.
• If you develop confusion, swelling, or shortness of breath, see a doctor quickly.

Book a routine appointment if:

• If you have diabetes, high blood pressure, or a family history of kidney disease, ask your doctor about regular kidney function tests.
• If you have had repeated kidney infections or kidney stones, talk to your doctor about whether your kidneys need imaging.

Diagnosis

An atrophic kidney is usually found when an imaging test, such as an ultrasound, CT scan, or MRI, shows that one kidney is smaller than the other. Blood and urine tests are used to check how well your kidneys are filtering waste and whether there is any protein or blood in your urine.

Tests that may be done

• Ultrasound of the kidneys
• CT scan or MRI of the abdomen (if needed)
• Blood tests to measure creatinine and estimate glomerular filtration rate (eGFR)
• Urine test to look for protein, blood, or signs of infection
• Blood pressure measurement

What to expect at your appointment

Your doctor may repeat these tests over time to see whether the kidney is getting smaller or whether your overall kidney function is staying stable. If there is concern about the cause or if kidney function is declining, you may be referred to a kidney specialist (nephrologist).

Treatment

Treatment depends on the cause. The main goals are to slow or stop any further kidney damage, manage symptoms, and protect the healthy kidney tissue you still have. If the atrophic kidney is not causing symptoms and the other kidney is working well, you may not need any treatment other than monitoring.

Self-care at home

• Take all medicines your doctor prescribes, even if you feel fine.
• Reduce salt in your diet to help control blood pressure.
• Drink enough water, unless your doctor tells you to limit fluids.
• Avoid nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen unless your doctor says they are safe for you.
• If you smoke, ask for help to quit.
• If you have diabetes, keep your blood sugar in the target range your doctor sets.

Medical treatments

Medical treatment is tailored to the cause. It may include medicines to lower blood pressure, control blood sugar, or protect the kidney from further damage. If an infection is present, antibiotics may be used. If a blockage such as a kidney stone is causing back-pressure on the kidney, it may be removed or treated. A kidney specialist will adjust treatment based on your specific situation.

When is surgery considered?

Surgery is rarely needed. In some cases, the atrophic kidney may be removed if it causes repeated infections, severe pain, or high blood pressure that cannot be controlled. Your doctor and a surgeon will discuss this with you only if it is necessary.

Living with this condition

Most people with an atrophic kidney live full and active lives. The most important thing is to protect your remaining kidney function by keeping regular appointments, taking any prescribed medicines, and staying on top of conditions like high blood pressure and diabetes.

Lifestyle tips

• Keep blood pressure and blood sugar within the targets your doctor sets.
• Eat a balanced diet with plenty of vegetables, fruit, whole grains, and lean proteins.
• Limit salt to help control blood pressure and reduce strain on your kidneys.
• Stay active with regular walking, cycling, or swimming.
• Avoid smoking and limit alcohol intake.

Diet and exercise

A kidney-friendly eating plan is usually about balance and portion control. Your doctor or a dietitian can help you adjust your diet if your kidney function is reduced. This may mean limiting salt, and in later stages of kidney disease, managing potassium and phosphorus intake. Exercise, such as 30 minutes of brisk walking most days, can improve blood pressure, weight, and overall well-being, but check with your doctor before starting a new exercise routine.

Mental health and emotional wellbeing

Learning that you have a kidney condition can be worrying. It is normal to feel anxious or stressed. Talking about your concerns with family, friends, or a counselor can help. If you are struggling, consider reaching out to a mental health professional or asking your healthcare team for support. If you are in emotional distress, do not hesitate to seek help.

Prevention

It may not always be preventable, especially if it runs in the family or is present at birth. However, you can reduce your risk of kidney damage by controlling blood pressure, managing diabetes, avoiding smoking, staying active, and using painkillers carefully.

Vaccines

Keep your vaccinations up to date, including the annual flu vaccine and COVID-19 boosters recommended by your local health service. Preventing infections can help reduce stress on your kidneys.

Screening programmes

If you have diabetes, high blood pressure, or a family history of kidney disease, regular blood pressure checks and kidney function tests are a good idea. Ask your doctor how often you should be screened.

Complications

If left untreated

• If the underlying cause is not managed, the remaining kidney tissue may become more damaged over time.
• Overall kidney function may decline, leading to chronic kidney disease.
• In advanced stages, kidney failure may develop, requiring dialysis or a kidney transplant.
• High blood pressure, anemia, and bone disease may become more likely.

Long-term outlook

The outlook is often very good, especially when the other kidney is healthy. Many people with an atrophic kidney never need treatment and their kidney function stays stable for years. With good medical care and healthy habits, most people can continue to live a normal, active life.

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