Acute kidney injury (AKI)

Causes of acute kidney injury

Lots of things can cause acute kidney injury (AKI). The problem may be in your kidneys or somewhere else in your body.

Possible causes include:

• infections or sepsis
• dehydration, low blood pressure or blood loss
• conditions that can cause swelling or a blockage, like kidney stones, an inflamed prostate (prostatitis), tumours or inflamed blood vessels (vasculitis)
• long-term conditions that affect your kidneys, heart or liver
• long-term use of some medicines, such as ACE inhibitors, anti-inflammatory medicines (NSAIDs) or medicines that make you pee more (diuretics)
• the dye (contrast) sometimes injected as part scans, such as a CT scan or coronary angiography

Anyone can get AKI, but it's more common if you:

• are aged 65 or older
• have had AKI before
• have recently had surgery
• take illegal drugs

Symptoms of acute kidney injury

Many people do not get symptoms of acute kidney injury (AKI), especially if it's mild.

If you do get symptoms, they may include:

• peeing a lot less than usual
• feeling very thirsty
• feeling sick (nausea) or being sick (vomiting)
• swollen feet or legs
• feeling tired, dizzy, confused or sleepy
• feeling breathless, especially when you lie down

How acute kidney injury is diagnosed

Acute kidney injury (AKI) is diagnosed using a blood test. Your blood will be checked for levels of creatinine, a waste product made by your muscles and removed by your kidneys.

If you have higher levels of creatinine than usual, it means your kidneys are not working as well as they should.

If a doctor thinks you have AKI, they may also:

• ask you to give a sample of pee (urine sample)
• ask how often you've been peeing
• check your pulse and blood pressure

Depending on what they think may be causing your symptoms, you may also have other tests, including:

• an ECG (electrocardiogram)
• scans such as an X-ray, CT scan or ultrasound

If your AKI is severe or they're not sure what's causing it, you may be referred to a kidney specialist (nephrologist) or admitted to hospital.

AKI is often diagnosed if you're having tests or have been admitted to hospital for another reason.

Treatment for acute kidney injury

Treatment for acute kidney injury (AKI) depends on how bad it is and what's causing it. You may need treatment in hospital.

Treatment may include:

• medicine – this could be to treat an infection, raise your blood pressure, reduce swelling or calm your immune system
• stopping or changing any medicine that could be causing damage to your kidneys
• fluids given into your vein through a drip (IV)
• a thin, flexible tube (catheter) being put into your bladder to drain urine
• surgery to remove a blockage in your kidneys or bladder

If your AKI is severe, your kidneys may need help to do their job of cleaning your blood, which can be done using a machine during dialysis.

This is usually just for a few days or weeks until your kidneys recover.

Complications of acute kidney injury

Acute kidney injury (AKI) is a serious condition and can be life-threatening if not treated, but many people recover fully within a few weeks with no long-term effects.

If your AKI is more serious, it can take several months to recover.

You'll have regular blood tests and check-ups after you've recovered to make sure your kidneys are working as expected.

Some people who have had AKI end up with permanent damage to their kidneys, causing chronic kidney disease.

You're more likely to get chronic kidney disease if your AKI is severe or you already have other long-term health problems.

Chronic kidney disease is a lifelong condition that increases your risk of cardiovascular disease, such as a heart attack or stroke, and may mean you'll need regular dialysis. But it can often be managed through lifestyle changes.

How to lower your chances of acute kidney injury if you're at higher risk

If you've had acute kidney injury (AKI) before or you're at higher risk of getting it because of your age or medication you take, there are some things you can do to lower your chances of getting it.