What Is Acute Kidney Injury?

Acute kidney injury (AKI)—sometimes called acute renal failure—is a sudden and serious drop in how well your kidneys work. It can develop within hours or days and may lead to the buildup of waste, fluid, and electrolyte imbalances in the body. Unlike chronic kidney disease, which develops slowly over time, AKI happens quickly and often requires urgent medical care.

AKI is not a disease itself, but a complication of other health problems. Common causes include:

• Severe infections (sepsis)
• Dehydration
• Blood loss or low blood pressure
• Toxic reactions to medications
• Blockages in the urinary tract

When the kidneys are injured, they can no longer filter waste or regulate fluid levels properly. This can lead to swelling, shortness of breath, confusion, and changes in urination—though some people may not have noticeable symptoms early on.

Doctors usually detect AKI by checking blood creatinine levels (which rise when the kidneys are not working) and urine output (which often decreases). A sudden increase in creatinine or a drop in how much urine is made can signal that the kidneys are in trouble.

Treatment for AKI depends on the cause. It may involve IV fluids, medication adjustments, or treating infections or blockages. In severe cases, dialysis may be needed temporarily until the kidneys recover.

The good news is that AKI can often be reversed, especially if it is caught and treated early. However, it can also lead to permanent kidney damage if not managed properly, especially in older adults or people with pre-existing kidney conditions.

If you or someone you care for is in the hospital or dealing with a serious illness, it is important to be aware of the risk of acute kidney injury and to act quickly if there are signs of kidney trouble.

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