HealthInfo West Coast-Te Tai Poutini
Acute kidney injury
Whara whanewhane ohotata
Acute kidney injury (also called acute kidney failure) affects both your kidneys. It means that they have suddenly stopped working properly. This can happen over a few hours, days or weeks. It can range from a minor loss of kidney function to complete kidney failure.
It is essential that acute kidney injury is found early. The earlier it is picked up, the better the chance of your kidneys fully recovering.
Acute kidney injury can happen at any age. But it is more common if you are aged 65 or over and if you have a long-term disease such as heart failure, liver disease or diabetes.
Causes of acute kidney injury
Most cases of acute kidney injury are caused by reduced blood flow to the kidneys. This usually happens in someone who is already unwell with another health condition.
This reduced blood flow could be caused by:
- low blood volume after bleeding, excessive vomiting or diarrhoea, or severe dehydration
- your heart pumping out less blood than normal as a result of heart failure, liver failure or sepsis
- certain medicines that reduce blood pressure or blood flow to the kidneys, such as ACE inhibitors, certain diuretics or NSAIDs.
Acute kidney injury can also be caused by:
- a problem with the kidney itself, such as inflammation of the filters in the kidney (glomerulonephritis), the blood vessels (vasculitis) or other structures in the kidney
- a blockage affecting the drainage of your kidneys, such as:
- an enlarged prostate
- a tumour in your pelvis, such as an ovarian or bladder tumour
- kidney stones.
Symptoms of acute kidney injury
You can sometimes have acute kidney injury without any symptoms, and it is only picked up by a blood test.
Common symptoms of acute kidney injury include:
- passing less urine (wee) than usual or no urine
- loss of appetite
- feeling sick or vomiting
- feeling confused, anxious and restless or sleepy
- swelling of your legs or other body parts
- pain in your stomach or lower back.
Diagnosing acute kidney injury
Acute kidney injury is usually diagnosed from a blood test that measures the level of a substance called creatinine in your blood. High levels of creatinine mean that your kidneys are not getting rid of waste products as well as they should.
Sometimes a sample of your urine will be checked for blood and protein.
An ultrasound scan of the kidneys may be done to pick up any blockages.
In rare cases, you may need a kidney biopsy to work out what is causing your acute kidney injury. This involves taking a very small sample of tissue from one of your kidneys.
Treating acute kidney injury
There is no specific treatment for acute kidney injury. The treatment aims to manage your symptoms and treat the underlying cause.
Sometimes you need dialysis to clean your blood by filtering out waste products and fluid until your kidneys recover.
Long-term effects
Acute kidney injury can be reversible, but it may take some time for your kidneys to recover. You may get your normal kidney function back or you may only get some of it back.
Some people may have permanent kidney damage that needs dialysis. This is called chronic kidney disease.
People who have a history of acute kidney injury have a higher risk of developing chronic kidney disease in the future.
Following acute kidney injury, you should get your kidney function checked by your doctor every year for the first 3 years.
HealthInfo recommends the following pages
- NHS – Acute kidney injury
Information about acute kidney injury, including possible causes and who is at risk of getting it.
Written by HealthInfo clinical advisers. Last reviewed March 2025.
Sources
Review key: HIKID-202879
