Definition

Acute kidney injury (AKI) is the sudden loss of kidney function. Kidneys clean wastes from the blood and maintain fluid levels in the body.

Problems can happen:

• Before blood enters the kidneys
• Inside the kidneys (most common)
• When urine leaves the kidneys and moves toward the bladder

Anatomy of the Kidney Copyright © Nucleus Medical Media, Inc.

Causes

AKI has many causes:

• Blood is blocked from going into the kidneys because of:
  • Problems with blood vessels
  • Blood loss
  • Excessive fluid loss— dehydration
  • Infection
• Problems inside the kidney cause tissue death because of:
  • Problems after surgery
  • Inflammation
  • Blood clots
  • Medicine side effects
• Kidney stones
• Enlarged prostate

Risk Factors

AKI is most common in older adults and females. Your chances are also higher if you have:

• Diabetes
• High blood pressure
• Kidney, liver, or heart disease
• Dehydration
• Bleeding from the stomach or intestines
• Taken certain medicines
• Used illegal drugs
• Problems after surgery or a hospital stay
• Overused certain nonsteroidal anti-inflammatory drugs (NSAIDs)
• Used angiotensin converting enzyme (ACE) inhibitors
• Blockages, which can happen with benign prostatic hyperplasia or a bladder tumor

Symptoms

Most people do not have symptoms. In those that have them, AKI may cause:

• Lower or higher amounts of urine than normal
• Fatigue
• Confusion
• Nausea or vomiting
• Muscle weakness
• Muscle cramps
• Lack of hunger
• Swelling
• Weight gain

Diagnosis

The doctor will ask about your symptoms and health history. You may also have:

• A physical exam
• Blood and urine tests—to look for levels of certain proteins
• Imaging tests:
  • Kidney ultrasound
  • CT scan
  • MRI scan
  • MRA scan

You may be referred to a specialist for care.

Treatment

Care depends on the cause of AKI and how serious it is. Care may involve:

• Stopping or changing medicines causing harm to your kidneys
• Dietary changes that limit how much protein you eat
• IV fluids
• Dialysis —a machine works for your kidneys by filtering your blood
• Caring for problems such as kidney stones or infections
• Kidney transplant
• Dialysis —a machine used to filter waste from the blood

Prevention

To lower your chances of AKI, don’t take medicines you know cause kidney problems. Your doctor will find other medicines to help you.