Acute Kidney Injury (AKI) A&E leaflet

Download and print as a PDF (221kB pdf)

What do the kidneys do?

Most people have two kidneys, located near the back of their tummy. Each kidney is about 10–12 cm (4–5 inches) long and shaped like a bean. 

The kidneys: 

• Remove waste and extra fluid from the body by making urine 
• Help control blood pressure and salt levels 
• Help produce red blood cells 
• Make hormones that keep your body healthy 

What is acute kidney injury (AKI)?

AKI happens when your kidneys suddenly stop working properly. This can be mild or severe. If not treated early, it can be life-threatening. Starting treatment early helps recovery. 

Common causes of AKI:

• Dehydration (often from vomiting or diarrhoea) 
• Infections 
• Certain medications 
• Blockages in the tubes (ureters) between the kidneys and bladder 

AKI is not the same as chronic kidney disease (CKD). CKD is a long-term condition. 

What are the symptoms of AKI?

Common symptoms are:

• Passing less urine than usual.
• Unexplained loss of appetite.
• Feeling sick or vomiting.
• Swelling in your legs or body
• Feeling short of breath

Sometimes, there are no symptoms, and AKI is only found with a blood test.

What causes AKI?

AKI can be caused by many things. These include:

• Dehydration, often from vomiting or diarrhoea. 
• Infections. 
• Certain medicines, such as: 
  • Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or diclofenac. 
  • Blood pressure medications such as ramipril, enalapril, losartan, or candesartan. 
  • Diuretics (water tablets) like furosemide or bumetanide. 
• Blockages in the tubes connecting the kidneys to the bladder.

People at higher risk of AKI include older adults and those with existing conditions such as kidney disease, heart failure, or diabetes. 

How is AKI diagnosed?

AKI is usually diagnosed with a blood test that checks creatinine levels (a waste product). High levels mean your kidneys aren’t working properly. 

You might also need: 

• A urine test (dipstick) to check for blood or protein 
• An ultrasound scan to look for blockages 
• In rare cases, a kidney biopsy may be needed. This involves using a fine needle to take a small tissue sample. The procedure is done under local anaesthetic. 

How is AKI treated?

Treatment depends on the cause:

• Fluids can be given if you are dehydrated 
• Antibiotics may be prescribed if you have an infection   
• A tube (catheter) might be inserted into the bladder if there is a blockage 

In rare cases, steroids or other drugs may be needed to prevent further kidney damage. 

Will my kidneys get better?

For most people, kidney function returns to normal with treatment.

• You’ll need regular blood tests to monitor recovery 
• In some cases, temporary dialysis (a machine to clean the blood) is needed 
• Very rarely (3 in 100 people), kidney damage is permanent and long-term dialysis is required 

Can AKI happen again?

Yes. If you have had AKI once, you are more likely to get it again or develop chronic kidney disease later. It is important for long-term monitoring with your GP. 

What happens when I go home?

If your AKI is improving, you may be discharged from hospital. 

To help your recovery: 

• Book a blood test with your GP in one week 
• Drink enough fluids to keep your urine pale yellow (unless you’ve been told to limit fluids intake for example due to heart failure). 

When to seek medical help

Further support

For general medical advice please use the NHS website, the NHS 111 service, walk-in centres, or your GP.

The NHS website provides online health information and guidance.

There are walk-in and urgent treatment services at Brighton Station, Crawley Urgent Treatment Centre, Lewes Victoria Hospital, Horsham Minor Injuries Unit and Bognor Regis War Memorial Hospital.