Acute Tubular Necrosis

Acute tubular necrosis (ATN) is a serious condition that damages the tube-shaped structures (tubules) in your kidneys. Tubules filter out waste products and fluids from your blood. “Acute” means the condition starts suddenly. “Necrosis” implies cell death. But even though it causes serious kidney dysfunction, there’s limited necrosis.

ATN is the most common cause of acute kidney injury. Experts estimate that acute kidney injury affects more than 13 million people globally. ATN doesn’t usually cause symptoms. But in severe cases, you may have symptoms like peeing problems, nausea and confusion. These are signs of kidney failure.

To treat ATN, healthcare providers must address the underlying cause. In severe cases, you may need dialysis to do the work of your kidneys.

Other names for acute tubular necrosis include:

• Acute renal necrosis
• Acute renal tubular necrosis
• Acute tubular injury (ATI)

What are the four phases?

Healthcare providers usually divide acute tubular necrosis into four phases:

• Initial injury: This is the underlying injury. It causes an increase of waste products (creatinine, nitrogen) in your blood. This phase may last for hours or days.
• Extension: This phase connects the initial injury and maintenance phases. Low oxygen levels (hypoxia) and inflammation occur, particularly at the area that connects the outer and inner parts of your kidney (corticomedullary junction).
• Maintenance: During this phase, your kidneys don’t filter your blood as well as they start to heal, and your body removes damaged tubules. You may pee less than usual (oliguria). This phase usually lasts between one and three weeks.
• Recovery: Your kidney function slowly improves as your tubules repair. Blood flow to your kidneys returns to a normal range. You may pee a lot more than expected. This phase may last for up to two weeks.

Symptoms of acute tubular necrosis

ATN usually doesn’t have any symptoms. But in severe cases, it may cause acute kidney failure. This may include symptoms like:

• Peeing less than usual or not at all
• Swelling (edema) and fluid retention
• Nausea and vomiting
• Feeling sluggish and weak
• Confusion

What causes acute tubular necrosis of the kidneys?

The most common causes are conditions that reduce blood flow and oxygen to your kidney (ischemia of the kidneys), damaging the tubules. These include conditions like:

• Stroke
• Heart attack
• Sepsis
• Pancreatitis
• Significant blood loss from an injury or surgery

Certain chemicals can also cause ATN. These include:

• Contrast dye
• Anesthesia drugs
• Certain medications, including aminoglycoside antibiotics, colistimethate (colistin), vancomycin, NSAIDs and antifungal medications (like amphotericin)
• Toxic chemicals, including ethylene glycol
• Cisplatin and other chemotherapy drugs

Risk factors

You’re at a greater risk of ATN if you have:

• Reduced blood flow, like from a blood clot
• Liver disease
• Diabetes
• Blood transfusion reaction
• Low blood pressure (hypotension) over a long period
• Septic shock
• Blood loss from surgery
• Muscle damage (rhabdomyolysis)

You’re also more likely to have ATN if you’re at least 65 or have an underlying kidney condition.

How doctors diagnose acute tubular necrosis

Your healthcare provider will review your medical history and perform a physical exam. If they suspect ATN, they may refer you to a nephrologist. Nephrologists are kidney specialists. They’ll recommend kidney function tests to look for:

• Blood urea nitrogen (BUN), which is a waste product when protein breaks down
• Serum creatinine, which is a waste product when muscle tissue breaks down
• Electrolyte levels in your blood, including potassium
• Water and waste products in your pee, including sodium (salt)

They’ll also recommend pee tests to help rule out other conditions that cause kidney injuries. Tests may include:

• Urine microscopy: A provider examines your pee sample under a microscope to look for ATN characteristics.
• Fractional excretion of sodium (FENa): This test looks at how much sodium is in your pee. If it’s higher than 1%, you may have ATN. If it’s less than 1%, you may have another cause of kidney injury, like dehydration.
• Urine osmolality: This test measures the concentration of different particles in your pee. If it’s less than 350 milliosmols per kilogram (mOsm/kg), you may have ATN. If it’s greater than 500 mOsm/kg, you may have another cause.

If your provider can’t make a proper diagnosis from kidney function tests, they may recommend:

• An abdominal ultrasound to make sure your symptoms aren’t due to a blockage (obstruction)
• A kidney biopsy to look for inflammation

How do you fix acute tubular necrosis?

Treating the underlying cause is very important. It allows your kidneys the chance to heal. ATN treatment may include:

• Stopping any medications that damage your kidneys
• Changing what you eat to limit sodium and potassium
• Drinking less fluids
• Taking diuretics to help you pee more
• Taking potassium binders to help remove excess potassium from your blood
• Going on temporary dialysis to filter waste products from your blood

Can you recover from it?

Yes, you can recover from acute tubular necrosis. With successful diagnosis and treatment, your kidneys will heal without permanent damage. But it takes a little longer for some people compared to others. People who respond quickly to treatment can recover within one to three weeks. If you have underlying medical conditions or other illnesses, it may take longer.

But it's important to know that if you have ATN, you have a higher risk of developing chronic kidney disease (CKD) and kidney failure. You may be more likely to progress to late-stage CKD than people with other types of acute kidney injuries. If the tubules don’t repair themselves completely, you’re also at risk of developing a buildup of scar tissue in your kidney (fibrosis) and permanent kidney damage. 

When should I see my healthcare provider?

Schedule follow-up appointments with your healthcare provider, even if you make a full recovery. They’ll do blood tests to make sure your kidneys are still functioning as they should.

You should also see your provider if you have symptoms of kidney failure, like peeing less than usual, swelling and fatigue.

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

• What caused ATN?
• Will my kidneys fully recover?
• What treatment do you recommend?
• How long will I need treatment?
• Will I need dialysis?
• Am I at risk of chronic kidney disease?
• Is there anything I can do to keep my kidneys healthy?
• What symptoms should I look out for in the future?

What can I expect if I have acute tubular necrosis?

Your outlook depends on:

• The underlying cause
• Your overall health
• How much you’re peeing
• How quickly you get treatment

If you’re relatively healthy and peeing as expected, acute tubular necrosis can be reversible. Many people regain kidney function within several weeks.

If you have other health conditions (like heart or lung conditions) and are peeing less than expected, your recovery may take longer. You also may not regain kidney function, which may require lifelong dialysis. Your healthcare provider will give you a better idea of what to expect.

Life expectancy

In general, ATN shouldn’t affect your life expectancy if it’s mild and you get proper treatment quickly. But if the underlying cause is severe and you need dialysis, ATN can lower your life expectancy or even be fatal.