Patient education
Acute Kidney Injury (AKI)
Acute kidney injury means the kidneys lose function suddenly — over hours or days — rather than gradually. It is usually detected as a rapid rise in creatinine or a fall in urine output. Treated early, kidney function often recovers.
The basics
What happens in AKI?
In AKI the kidneys can no longer clear waste and balance fluid properly. Because the change is fast, waste products and fluid can build up quickly.
Creatinine and urea rise quickly
Urine output may fall (or stay normal)
Potassium and acid can build up
Fluid may collect in the legs or lungs
Blood pressure can swing high or low
Often found on a routine blood test
What can cause AKI?
Causes are grouped by where the problem lies — reduced blood flow to the kidney, damage within the kidney itself, or an obstruction to urine flow.
Recognising it
AKI can be quiet at first
Some people feel completely well and AKI is picked up only on a blood test. When symptoms do appear, they can develop rapidly.
If you are unwell with vomiting, diarrhoea or fever and are taking blood pressure, diabetes or diuretic medicines, ask your doctor whether any should be paused — this is often called sick-day guidance.
Possible symptoms
- Passing much less urine than usual
- Swelling of the legs, ankles or face
- Tiredness and confusion
- Nausea or vomiting
- Breathlessness
- Chest discomfort
Diagnosis
How is AKI assessed?
Blood tests
Creatinine, urea, electrolytes and acid-base status show how severe the injury is and how quickly it is changing.
Urine tests
Urine is examined for protein, blood, cells and casts — these clues help distinguish between the possible causes.
Ultrasound
A kidney ultrasound checks kidney size and looks for any blockage to urine flow, which can often be relieved quickly.
Treatment
How AKI is managed
There is no single pill for AKI. Treatment means correcting the cause and supporting the kidneys while they recover.
- 01
Treat the underlying cause
Infection is treated, bleeding is controlled, and any obstruction to urine flow is relieved. This is the single most important step.
- 02
Restore fluid balance
Fluids are given if you are dehydrated, or restricted and removed if fluid has overloaded the body. Balance is monitored closely.
- 03
Stop kidney-harming medicines
Painkillers such as ibuprofen and diclofenac, some antibiotics and certain blood pressure medicines may be paused or dose-adjusted.
- 04
Correct electrolytes
High potassium and acid build-up are treated promptly because they can affect the heart.
- 05
Dialysis, if needed
A minority of people need temporary dialysis while the kidneys recover. This is usually short-term, not lifelong.
- 06
Follow up afterwards
Kidney function should be rechecked after recovery. An episode of AKI raises the future risk of chronic kidney disease, so ongoing monitoring matters.
When should you seek medical help?
Contact your doctor if you have
- A marked reduction in urine
- New or rapidly increasing swelling
- Ongoing vomiting or diarrhoea
- A recent blood test showing a rise in creatinine
- Fever with feeling very unwell
Seek urgent medical attention for
Severe breathlessness, chest pain, confusion or drowsiness, or passing almost no urine at all.
The most important message
AKI is a warning signal, not a life sentence. Found and treated early, kidney function frequently recovers — and follow-up protects you afterwards.
Ask your doctor to recheck your kidney function after an AKI episode.
If you are concerned about your kidney health, speak with a qualified healthcare professional. This information is for patient education and does not replace individual medical advice.