Acute kidney injury

Acute kidney injury (AKI) means that your kidneys have suddenly stopped working as well as they used to. This might have happened in the past few hours, days or weeks.

• Acute kidney injury affects both your kidneys and can range from minor loss of kidney function to complete kidney failure.
• If it's not picked up in time, the kidneys can deteriorate quite quickly and shut down. This can lead to permanent damage and can be life threatening if not detected early and treated quickly. 
• AKI is not the same as chronic kidney disease (CKD), in which your kidneys lose their function gradually over a long period of time.
• CKD often goes unnoticed until your kidney function is significantly impaired, and does not get better with time. Read more about chronic kidney disease.

AKI can happen at any age, but it is more common in older people and in people who are in hospital.

You are at increased risk of AKI if you:

• already have a kidney problem, such as chronic kidney disease
• have a long-term disease such as heart failure, liver disease or diabetes
• are dehydrated, eg, when you have diarrhoea, vomiting, or 'gastro' (a tummy bug)
• have an infection 
• have a blockage of one or both of the tubes leading from your kidneys to your bladder, such as kidney stones, or an enlarged prostate 
• are taking some medicines, especially if you take them while you are unwell.

Medicines and acute kidney injury

Taking some medicines increases your risk of getting AKI, especially if you take these medicines while you are dehydrated, or you take a combination of these medicines.

Read more about how you can protect your kidneys.

The most common symptoms are:

• passing less urine (pee) than usual
• very concentrated urine, or urine looking yellow/brown/red in colour
• loss of appetite
• feeling sick (nausea) or vomiting
• feeling tired and short of breath
• feeling confused, anxious and restless, or sleepy
• swelling of your legs or other body parts
• pain in your abdomen or lower back.

Sometimes AKI can occur without any symptoms and can only be picked up by a blood test.

AKI 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 urine will be checked for blood and protein (dipstick test) and an ultrasound scan of the kidneys will be done to pick up any blockages. 

In rare cases, a kidney biopsy may be needed to work out what is causing AKI. This involves taking a very small sample of tissue from one kidney using a fine needle. The area will be numbed using local anaesthetic.

After AKI you can make a full recovery and have normal kidney function or you can make a partial recovery with lower levels of kidney function. Some people may have permanent kidney damage that requires dialysis.

After AKI your kidney function can continue to recover over time. People who have a history of AKI have a higher risk of chronic kidney disease. It is recommended that you get your kidney function checked out by your doctor every year for the first 3 years following an AKI.

The following links provide further information on acute kidney injury. Be aware that websites from other countries may contain information that differs from New Zealand recommendations.

Acute kidney injury(external link) Kidney Health Australia
How to prevent acute kidney injury if you are sick or dehydrated(external link) Kidney Health Australia  
Acute kidney injury(external link) NHS, UK

How to protect your kidneys
Kidney health topics
Dehydration in adults
Non-steroidal anti-inflammatories (NSAIDs)

1. Acute kidney injury(external link) J R Coll Physicians Edinb 2013; 43:323–9
2. Acute-on-chronic kidney disease – prevention, diagnosis, management and referral in primary care(external link) BPAC, NZ, 2012

The following information on acute kidney injury(external link) is taken from Auckland Regional HealthPathways, NZ, accessed October 2020:

Beware the "triple whammy" effect

Beware of the "triple whammy" effect in patients prescribed an ACE inhibitor or ARB, and a diuretic, in combination with an NSAID.

Clinical resources

Avoiding acute kidney injury in primary care – attitudes and behaviours of general practitioners and community pharmacists in Hawke’s Bay(external link) Journal of Primary Health Care, NZ, 2020
Proton pump inhibitors and the risk of acute kidney injury(external link) BPAC, NZ, 2016
Acute-on-chronic kidney disease – prevention, diagnosis, management and referral in primary care(external link) BPAC, NZ, 2012
Statins and the risk of acute kidney injury(external link) BPAC, NZ, 2013