Acute kidney injury (AKI) means the kidneys suddenly stop working properly over hours or days. It is different from chronic kidney disease, which develops slowly over years. AKI is common in people who are seriously ill or dehydrated — and with prompt care, the kidneys often recover.
What causes AKI?
Doctors group the causes into three types based on where the problem starts:
Before the kidney
Reduced blood flow — from severe dehydration, blood loss, infection (sepsis), or heart problems.
Within the kidney
Direct damage from certain medicines, toxins, contrast dyes, or inflammation of the kidney tissue.
After the kidney
A blockage to urine flow — such as kidney stones, an enlarged prostate, or a tumour.
Warning signs
- Passing much less urine than usual
- Swelling in the legs, ankles or face
- Tiredness, nausea or confusion
- Shortness of breath
Common triggers to avoid
Dehydration combined with NSAID painkillers, certain antibiotics, or contrast scans can tip vulnerable kidneys into AKI. If you are unwell and not drinking, ask your doctor whether to pause such medicines temporarily ("sick-day rules").
What happens to the kidneys during acute injury.
Treatment and recovery
Treatment focuses on the underlying cause: restoring fluids, treating infection, stopping harmful medicines, or relieving a blockage. In severe cases, temporary dialysis supports the body while the kidneys heal. Many people recover fully, though some are left with a degree of long-term kidney weakness — which is why follow-up testing after AKI is important.
After an episode of AKI
Even after recovery, an episode of AKI raises your future risk of chronic kidney disease. A repeat kidney check a few weeks later helps make sure function has returned to baseline.
References & Further Reading
- National Kidney Foundation. "Acute Kidney Injury (AKI)." kidney.org
- KDIGO Clinical Practice Guideline for Acute Kidney Injury. kdigo.org
- NIDDK, National Institutes of Health. Kidney Disease Information. niddk.nih.gov
This article is for general education only and does not replace personalised medical advice. Seek urgent medical care if you develop the warning signs described above.