Acute Kidney Injury

Acute kidney injury (AKI) is a sudden decline in kidney function occurring over hours to days, resulting in the build-up of waste products and fluid in the body. It is often reversible if identified and treated promptly, but can be life-threatening if missed.

• Reduced urine output
• Swelling of the legs, ankles, or around the eyes
• Fatigue and confusion
• Nausea and loss of appetite
• Shortness of breath if fluid builds up in the lungs
• Some cases, particularly early on, cause few noticeable symptoms and are found only on blood testing

• Reduced blood flow to the kidneys, such as from severe dehydration, blood loss, sepsis, or heart failure.
• Direct damage to the kidney tissue, from certain infections, medicines (including some antibiotics and NSAIDs used excessively), or toxins.
• Obstruction of urine flow, such as from an enlarged prostate, kidney stones, or a pelvic mass.
• Risk is increased by pre-existing kidney disease, diabetes, older age, and severe illness.

• Diagnosed using blood tests showing a rapid rise in creatinine (a marker of kidney function) together with reduced urine output.
• Assessment focuses on identifying and reversing the underlying cause — checking hydration status, reviewing medicines, and looking for obstruction or infection.
• Ultrasound may be used to check for obstruction of the urinary tract.

Treatment focuses on identifying and correcting the underlying cause — for example, giving intravenous fluids for dehydration, treating infection, stopping any kidney-harming medicines, or relieving an obstruction.

Careful monitoring of fluid balance, blood pressure, and electrolytes (particularly potassium, which can become dangerously high) is essential.

Severe cases with dangerous electrolyte disturbances, fluid overload, or failure to respond to initial treatment may require temporary dialysis at a specialist facility.

Most people recover kidney function if the underlying cause is treated promptly, though some may be left with reduced kidney function afterward.

• Stay well hydrated, particularly during illness with vomiting or diarrhoea.
• Avoid unnecessary or prolonged use of NSAIDs, especially in older adults or those with existing kidney or heart disease.
• Seek prompt treatment for infections and other acute illnesses.
• Attend regular monitoring if you have chronic kidney disease, diabetes, or heart failure, which increase the risk of AKI during illness.