Acute Kidney Injury: What You Need to Know

Overview

Acute kidney injury (AKI) is a sudden, temporary decrease in kidney function that develops over hours or days. Your kidneys normally filter waste, excess fluid, and electrolytes from your blood to make urine; when they are injured, these waste products build up in your body, which can cause serious health problems. AKI can happen to people with no prior kidney disease, and most cases are reversible if caught and treated early.

Signs & Symptoms

AKI symptoms can be mild or even absent in the early stages, especially if the injury is caught during routine testing for another condition. Common signs to watch for include:

• Decreased urine output (peeing less than usual, or not at all)
• Swelling in the legs, ankles, feet, or face from fluid buildup
• Fatigue, nausea, or confusion
• Shortness of breath from fluid collecting in the lungs
• Chest pain or pressure from fluid around the heart

Causes & Risk Factors

AKI occurs when something disrupts blood flow to the kidneys, damages kidney tissue directly, or blocks urine from leaving the body. The three main categories of causes are reduced kidney blood flow (from dehydration, severe infection/sepsis, heart failure, or significant blood loss), direct kidney tissue damage (from NSAIDs like ibuprofen, certain antibiotics, contrast dye used in imaging, or toxins), and urinary tract blockages (from kidney stones, an enlarged prostate, or tumors). You are at higher risk for AKI if you are older, have pre-existing chronic kidney disease, diabetes, high blood pressure, heart failure, or have recently had major surgery or a prolonged hospital stay.

Diagnosis

Your care team will diagnose AKI using blood and urine tests, a review of your medical history, and a physical exam. The key marker for AKI is a sudden rise in blood creatinine levels, a waste product normally filtered out by the kidneys. Your doctor may also order imaging tests like an ultrasound to check for blockages in the urinary tract.

Treatment & Management

Treatment for AKI depends on the cause and severity. Mild cases may only require temporary medication adjustments and increased fluid intake, while more severe cases require hospitalization. Common approaches include treating the underlying cause (e.g., antibiotics for infection, IV fluids for dehydration, surgery for blockages), adjusting or stopping kidney-damaging medications, and temporary dialysis for severe cases where kidneys cannot filter waste properly.

Living With It

Most people recover fully from AKI, but regular follow-up appointments to monitor kidney function are essential. These steps can help support recovery and reduce your risk of future kidney problems:

• Follow your care team’s fluid intake recommendations: Too little or too much fluid can harm recovering kidneys
• Take all prescribed medications exactly as directed, and tell every new provider you see that you have a history of AKI before starting any new medications
• Eat a kidney-friendly diet: Limit salt, processed foods, and excess animal protein, and follow any dietary guidance from your doctor or a registered dietitian
• Avoid over-the-counter NSAIDs like ibuprofen and naproxen unless your doctor explicitly says they are safe for you
• Monitor for symptoms of recurrence: Report any new swelling, decreased urine output, or unusual fatigue to your care team right away