Contrast-Associated Acute Kidney Injury (CA-AKI)

Contrast-associated acute kidney injury is when sudden kidney damage occurs within two days of receiving a contrast dye.

Contrast dye (iodinated contrast or iodine contrast medium) is a special fluid healthcare providers use. It helps make parts of your body — like blood vessels and organs — easier to see on imaging tests like CT scans. Contrast dye also makes it easier and safer for providers to perform certain procedures, including heart surgeries. Providers use a needle to inject it into a vein, and it travels through your bloodstream. Your kidneys eventually filter it out of your blood. It leaves your body in your pee.

For most people, contrast dye is safe. But some experts have concerns that it may cause contrast-associated acute kidney injury (CA-AKI). CA-AKI is a rare but serious condition that may cause chronic kidney disease (CKD) or make CKD worse. It may be fatal if you have severe CKD or kidney failure.

Older names for CA-AKI include:

• Contrast-induced nephropathy (CIN)
• Contrast-induced acute kidney injury (CI-AKI)
• Contrast-associated nephropathy
• Post-contrast acute kidney injury (PC-AKI)

These generally refer to the same condition.

What are the early symptoms of contrast-associated acute kidney injury?

It depends on how bad the kidney damage is. In mild cases, you may not have any symptoms. But if you have CKD, it may cause or make the following symptoms worse:

• Peeing less than usual
• Swelling, especially in your feet, ankles and legs
• Tiredness, weakness or low energy levels
• Confusion
• Itchy skin
• Loss of appetite
• Nausea and vomiting
• Diarrhea
• Pain on one or both sides of your back, between your hips and ribs (flank pain)
• Chest pain

Causes

Experts aren’t exactly sure why contrast dye causes CA-AKI in some people. But some suggested factors may include:

• Narrow or tight blood vessels (vasoconstriction)
• Too much contrast dye damages the tiny tubes (renal tubules) in your kidneys
• Problems with contrast dye and other fluids passing through kidney cell membranes
• Higher doses of contrast dye than recommended
• Certain types of contrast dyes, including gadolinium-based dyes

Risk factors

You’re at a greater risk of getting CA-AKI if you have:

• Severe chronic kidney disease (stages 4 and 5)
• Diabetes mellitus along with CKD
• Congestive heart failure
• High blood pressure
• Low body fluid levels

You’re also at an increased risk if you use nonsteroidal anti-inflammatory drugs (NSAIDs) and have one of the above conditions.

How to lower your risk

Before giving you a contrast dye, providers may conduct blood tests to check your estimated glomerular filtration rate (eGFR). Your eGFR helps providers understand how healthy your kidneys are. If it indicates kidney damage, your provider may recommend tests that don’t use contrast dyes.

Providers may give you IV fluids before or after giving you a contrast dye. This may help lower your risk.

How doctors diagnose contrast-associated acute kidney injury

Blood tests help healthcare providers diagnose it. They’ll look for an increase in your serum creatinine levels. When your muscle tissue breaks down, it creates the waste product creatinine. If you have CA-AKI, your serum creatinine levels are about 50% higher than usual within one week after receiving contrast dye. Providers may also look for an overall serum creatinine increase of 0.3 milligrams/deciliter within two days of receiving contrast dye.

How do you treat CA-AKI?

There’s no specific treatment after a contrast-associated acute kidney injury. Prevention is the best intervention.

If you’re at a higher risk for CA-AKI and your provider recommends contrast dye as part of your care plan, they may give you IV fluids. This helps balance your fluids, support your kidney function and lower your risk. They may also use a noniodinated contrast dye and limit how much dye they use.

In severe cases of CA-AKI, you may need dialysis. But this is rare. Dialysis filters wastes and extra fluids from your body when your kidneys don’t work as well as they should.

How long does it take to recover?

If you have healthy kidneys and experience mild damage, your kidney function will usually return to normal within two weeks. Most people who experience a CA-AKI, even with severe chronic kidney disease, will recover from CA-AKI. But your recovery depends on other factors. These include your overall health, the type of procedure you need and any other conditions you might have. Your healthcare provider will give you a better idea of what to expect.

When should I see my healthcare provider?

You should schedule follow-up appointments with your provider, even if you make a full recovery after contrast-associated acute kidney injury. They’ll do blood tests to make sure your kidneys are still functioning as expected.

You should also see your provider if you have symptoms of severe chronic kidney disease after CA-AKI.

During your appointments, you may want to ask your provider:

• What’s my risk of developing contrast-associated acute kidney injury?
• Do I need contrast dye, or are there other imaging test options?
• Should I schedule a blood test before the imaging tests?
• Should I stop taking any medications before or after the imaging test?

What can I expect if I have contrast-associated acute kidney injury?

It depends on your overall kidney health. In general, your outlook is better if you have mild CA-AKI and good kidney function before getting contrast dye. Most people recover kidney function in about two weeks.

• Between 2 and 3 out of 10 people who have chronic kidney disease, diabetes or high blood pressure will develop a CA-AKI.
• Less than 1 out of 100 people who don’t have diabetes will need dialysis.
• Around 10 to 15 out of 100 people who have diabetes and CA-AKI need dialysis.
• Around 2 out of every 10 people who need dialysis after CA-AKI need it for the rest of their lives.

Your provider will give you a better idea of what to expect.