15764 Kidney Ultrasound

Overview

A kidney ultrasound is a painless scan that uses sound waves to make pictures of your kidneys and the tubes and blood vessels around them. It is sometimes called a renal ultrasound. It does not use X-rays or radiation, so it is very safe and can be repeated whenever your doctor needs to check again. The scan shows the size and shape of your kidneys, whether urine can flow freely, and whether there are stones, cysts, swelling or changes in blood flow.

Yes. Kidney ultrasound is one of the most common imaging tests done in hospitals and clinics. It is often one of the first checks when someone has kidney or urinary symptoms, and it is also used regularly to keep an eye on kidneys that are already known to need watching.

People of any age can have a kidney ultrasound, from newborn babies to older adults. Babies may have one before birth as part of a pregnancy scan, or soon after birth if a kidney looked unusual. Adults often have one when they have side or back pain, blood in their urine, repeated urine infections, kidney stones, high blood pressure, or blood tests showing that their kidneys are not working as well as expected.

Symptoms

Common symptoms

• Pain in your side, back or lower belly that comes and goes
• Blood in your urine — the urine may look pink, red or cola-coloured
• Burning or stinging when you pass urine
• Needing to pass urine more often than usual, or suddenly
• Feeling sick or being sick along with the pain
• Fever or shivering with urinary symptoms
• Swelling in your legs, ankles or around your eyes
• High blood pressure found during a routine check
• Feeling very tired for no clear reason
• Blood tests showing that your kidneys are not filtering as well as they should

Symptoms in children

• A fever with no obvious cause, especially with a urine infection
• Poor feeding, vomiting or slow weight gain
• Swelling around the eyes, tummy or legs
• Wetting again after being dry at night for a while
• A kidney that looked unusual on a scan during pregnancy
• Passing urine very often, or straining to pass urine
• Tummy pain that keeps coming back

Symptoms in older adults

• Needing to pass urine often at night
• A weak stream or trouble starting to pass urine
• New confusion or unusual drowsiness, which can be a sign of infection
• Swollen legs or ankles
• Passing much less urine than usual
• Feeling very tired or breathless, which can be linked to kidney problems

Causes

Main causes

• A kidney ultrasound does not have a cause — it is a test. The reasons someone has one include:
• Kidney stones — hard lumps that form in the kidney and can block the flow of urine
• Urine infections, especially ones that keep coming back or go up into the kidney
• A blockage or narrowing somewhere in the urinary system
• Cysts (fluid-filled sacs) in the kidney
• High blood pressure, which can be both a cause and a result of kidney trouble
• A known kidney condition that needs regular checking
• Blood in the urine that needs to be looked into
• Diabetes, which can affect kidney function over time
• A kidney that looked unusual on a scan during pregnancy
• Checking a kidney before or after surgery, or checking a donated kidney

Risk factors

• Diabetes
• High blood pressure
• A family history of kidney disease or kidney stones
• Repeated urine infections, especially in children
• Not drinking enough fluids, which makes stones and infections more likely
• Being overweight
• Being older — kidney function naturally slows with age
• Some long-term medicines, which your doctor will explain if relevant to you

When to see a doctor

See a doctor urgently if:

• You have fever with pain in your side or back
• There is blood in your urine
• You are passing urine much less than usual, or it is painful to pass urine and getting worse
• You have been vomiting and cannot keep fluids down
• You have new swelling in your legs, hands or face

Book a routine appointment if:

• You keep getting urine infections
• You have a dull ache in your side that keeps coming back
• You have a family history of kidney disease and want to know what to do
• Your blood test showed your kidney function is lower than expected
• You have diabetes or high blood pressure and want to know about kidney checks
• You are waiting for results of a scan and want to understand what happens next

Diagnosis

The ultrasound is itself the test. You will be asked to lie on a couch, and a healthcare professional called a sonographer (a specialist in ultrasound scanning) or a radiologist (a doctor who specialises in scans) will put a clear gel on your skin and move a smooth handheld probe over your side, back and tummy. The gel may feel cool and slightly wet. The probe sends sound waves into your body, and pictures appear on a screen. You may be asked to hold your breath for a few seconds, or turn onto your side. You may also be asked to come with a full bladder, because a full bladder helps the pictures come out clearer — your appointment letter will tell you if so.

Tests that may be done

• Kidney ultrasound (renal ultrasound) — the main test
• Urine test to look for infection or blood
• Blood test to measure how well your kidneys are filtering
• Blood pressure check
• Other imaging such as a CT scan or a special X-ray, if the ultrasound leaves questions unanswered
• Sometimes a repeat ultrasound after some time, to see whether anything has changed

What to expect at your appointment

The scan is painless apart from the slight pressure of the probe. It usually takes about 15 to 30 minutes, and you can eat and drink normally unless you have been told otherwise. A full bladder is often needed, so you may be asked to drink water about an hour before and not empty your bladder just before the appointment. Afterwards you can wipe off the gel, get dressed and go home. The scan pictures are looked at by a specialist, who writes a report for the doctor who sent you. Results are usually ready within a few days to a couple of weeks, depending on your local service. Ask the clinic when and how you will hear back, so you are not left wondering.

Treatment

A kidney ultrasound is not a treatment. Its job is to help your healthcare team understand what is happening so they can agree on the right next step with you. If the scan is normal, you may not need any treatment at all. If something is found, the treatment will depend on what it is — for example, clearing an infection, helping a stone pass, relieving a blockage, or keeping a close eye on a kidney over time. Your doctor will explain the options and answer your questions before anything is decided.

Self-care at home

• Follow any preparation instructions on your appointment letter, such as drinking water beforehand
• Wear loose, comfortable clothing that is easy to move out of the way
• Write down your questions and any symptoms you have noticed, so you remember to mention them
• Bring a list of all your medicines, including anything you buy without a prescription
• Ask when and how you will get your results
• Drink plenty of water each day unless your doctor has told you to limit fluids

Medical treatments

What happens next depends on what the scan shows. For a urine infection, your doctor may prescribe a medicine to clear the infection. For high blood pressure, they may discuss ways to bring it down, including lifestyle changes and sometimes medicines. Small kidney stones may be managed with pain relief, fluids and time, while larger ones may need a procedure. Some findings, such as a simple cyst, often need no treatment at all — just a check later on. Your doctor will always explain why a particular option is being suggested, and you can ask about the benefits and downsides before deciding.

When is surgery considered?

Most people who have a kidney ultrasound do not need surgery. A procedure may be discussed if the scan shows a blockage that is not clearing, a stone that is too large to pass, a narrowing in the urinary system, or another problem that cannot be managed in other ways. Some procedures are small and done through a thin tube, while others are larger. Your specialist team would explain the reason, the risks and the alternatives with you beforehand.

Living with this condition

For most people, having a kidney ultrasound changes nothing about their daily routine. You go in, have the scan, and go home. The harder part is often the wait for results. Try to keep to your normal routine, and if you find yourself worrying, plan something to look forward to on the day you expect to hear back. If the scan leads to a diagnosis, your GP or specialist team will help you understand what it means for your everyday life and what to keep an eye on.

Lifestyle tips

• Drink water regularly through the day, unless you have been told to limit fluids
• Go to the toilet when you need to rather than holding on
• Keep up with any routine checks for blood pressure and kidney blood tests
• Take medicines as agreed with your doctor and ask before starting anything new, including herbal remedies
• Stop smoking if you smoke — this helps protect your heart and blood vessels, including those in your kidneys
• Keep a note of any new symptoms so you can mention them at your next appointment

Diet and exercise

A balanced diet and regular movement are good for your kidneys and your heart. Aim for plenty of vegetables and fruit, whole grains, and not too much salt or processed food. Drink water steadily rather than all at once. If you have a kidney condition, your doctor or a dietitian may suggest small changes — such as watching salt, or in some cases protein or potassium — based on your own test results. Being active most days, even a brisk walk, helps blood pressure and weight. Ask your GP if you are unsure what level of activity is right for you.

Mental health and emotional wellbeing

It is very normal to feel anxious before a scan or while waiting for results. Many people imagine the worst, and the waiting can feel long. Writing down your worries, telling someone you trust, and asking your clinic when to expect news can all help. If worry is affecting your sleep, appetite or mood for more than a couple of weeks, please speak to your GP — support is available and you do not have to manage alone. If you ever feel you cannot cope, contact your local crisis service or emergency services straight away.

Prevention

You cannot prevent needing a scan — it is a test, not an illness. But you can lower your chance of kidney problems by drinking enough water, keeping blood pressure and blood sugar in a healthy range, not smoking, staying active, and getting urine infections treated promptly. If you have a condition that can affect the kidneys, regular checks help find changes early, when they are usually easier to manage.

Screening programmes

There is no general screening programme for kidney disease in most countries. However, if you have diabetes, high blood pressure, heart disease, or a family history of kidney disease, your GP may suggest regular blood and urine tests, and sometimes an ultrasound. Speak to your doctor about whether checks are right for you.

Complications

If left untreated

• If a scan is delayed and a blockage or infection goes untreated, the kidney can become damaged over time
• Untreated urine infections can spread to the kidney and, rarely, into the bloodstream
• Large stones that block urine flow can cause severe pain and pressure on the kidney
• Some kidney conditions cause high blood pressure, which itself needs treating
• In some cases, long-term kidney damage can lead to reduced kidney function

Long-term outlook

The outlook is usually good. Most kidney ultrasounds either come back normal or show something that is easy to treat or simply needs watching. When something is found, catching it early is a real advantage, because many kidney problems can be managed well with treatment and small lifestyle changes. Your healthcare team will talk you through what your results mean for you and what happens next — and you are always welcome to ask questions until things feel clear.

Find support

External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.