What is azotemia?

Azotemia is a condition that happens when waste product levels in your blood are too high. Specifically, azotemia is when there’s too much nitrogen and waste products in your blood. These waste products develop when your body breaks down protein in foods and drinks you ingest. They form in your liver and travel in your blood to your kidneys. Healthy kidneys filter the waste products from your blood and leave your body through your urine (pee).

What are the types of azotemia?

The three types of azotemia include:

• Prerenal azotemia. Prerenal azotemia is the most common type of azotemia. It occurs when you don’t have enough blood flowing through your kidneys. Blood loss, dehydration, heart failure, liver failure, some medicines (including ibuprofen and aspirin) and other conditions may reduce blood flow to your kidneys.
• Intrinsic azotemia. Intrinsic azotemia typically occurs as a result of damage to your kidneys. Common causes include infection, sepsis, blood clots, certain medications (including chemotherapy drugs) and toxins such as drugs and alcohol.
• Postrenal azotemia. Postrenal azotemia occurs as a result of a blockage in your urinary tract. The blockage often happens in your ureters, which are tubes of muscle between your kidneys and bladder. Common causes include urinary tract infections (UTIs), ureteral stones and some forms of cancer.

Is azotemia the same as renal failure?

No, azotemia isn’t the same as kidney failure (renal failure). Kidney failure is the main cause of azotemia.

How common is azotemia?

Azotemia is common. It accounts for about 16% of hospital admissions.

What are the symptoms of azotemia?

Azotemia usually doesn’t have any symptoms that you can notice or feel until it reaches a later stage. Some people who have azotemia may not have any signs at any stage — a healthcare provider may discover you have it during tests for other conditions.

Azotemia symptoms may include:

• Not peeing a lot.
• Feeling very tired (fatigue).
• Feeling confused.
• Nausea and vomiting.
• Shortness of breath (dyspnea).
• Chest pain.
• Swelling, especially in your legs, ankles and feet (edema).
• Abnormal heartbeat (arrhythmia).
• Lack of appetite.

Severe azotemia symptoms may include seizures or coma.

What causes azotemia?

Azotemia causes depend on the type you have:

• Prerenal azotemia. Prerenal azotemia usually develops from an injury to a body part that affects how blood flows to your kidneys. Causes may include dehydration, blood loss from a damaged blood vessel (hemorrhage), burns, heart failure and liver failure.
• Intrinsic azotemia. Intrinsic azotemia develops after damage to your kidneys’ structures — including the tiny filters (glomeruli) that help remove waste, the small tubes that reabsorb and return water, nutrients and minerals (renal tubules) and the arteries and veins in your kidneys (renal vasculature). Conditions that cause inflammation often cause intrinsic azotemia, including vasculitis and infections. Toxins can also cause it. It can result from damage from low blood flow (hypoperfusion), as well.
• Postrenal azotemia. Blockages in your ureters and/or bladder usually cause postrenal azotemia. Risk factors include UTIs, ureteral stones, swollen kidneys (hydronephrosis) and an increase in the size of your prostate (benign prostatic hyperplasia).

Is azotemia the same as dehydration?

No, azotemia isn’t the same as dehydration. Dehydration is a common cause of prerenal azotemia. Dehydration may occur from:

• Not drinking enough water.
• Sweating.
• Vomiting.
• Diarrhea.
• Some medications, including diuretics (water pills), that make you pee a lot.

Is azotemia contagious?

No, azotemia isn’t contagious. You can’t spread azotemia to another person.

Who does azotemia affect?

Anyone can get azotemia. However, you’re more likely to get it if you’re 65 or older.

What are the complications of azotemia?

Azotemia can lead to a dangerous buildup of waste products in your blood (uremia). Uremia often results from chronic kidney disease (CKD). Without treatment, uremia can be fatal.

What is the difference between azotemia and uremia?

Azotemia and uremia are both conditions that affect your kidneys.

Azotemia is when you have too much nitrogen and other waste products in your blood.

Uremia is when you have too much urea and other waste products in your blood. Urea is a type of nitrogen waste product that forms in your liver after proteins break down.

How is azotemia diagnosed?

A healthcare provider who specializes in diagnosing and treating kidney conditions (nephrologist) will review your medical history, ask about your symptoms and conduct a physical examination. If they suspect azotemia, they’ll order a blood urea nitrogen (BUN) test and check your creatinine levels. Creatinine is a waste product of muscle tissue metabolism.

Tell your provider if you have a bleeding disorder or are taking any medications before your BUN test. They’ll disinfect your arm, use a thin needle to draw blood from a vein and then send your blood sample to a lab for testing.

What level of BUN indicates azotemia?

An expected blood urea nitrogen range varies according to your age and sex. Levels higher than this range may indicate azotemia.

Age and SexNormal BUN Level (mg/dL)Children between 1 and 17Between 7 and 20Adult people assigned male at birth (AMAB)Between 8 and 24Adult people assigned female at birth (AFAB)Between 6 and 21

A healthcare provider will also check your serum creatinine levels to diagnose azotemia. A serum creatinine range also varies according to age and sex. Levels higher than this range may indicate a kidney problem.

Age and SexNormal Serum Creatinine Level (mg/dL)Children between 1 and 160.2 to 0.9Adult people AMAB0.6 to 1.2Adult people AFAB0.5 to 1.1

What level of BUN indicates kidney failure?

Healthcare providers don’t use BUN to determine kidney failure. However, you likely have kidney failure if your BUN and creatinine numbers are higher than your baseline.

What other tests will be done to diagnose azotemia?

A healthcare provider may also order:

• Urinalysis. You’ll provide a pee sample to your provider, and they’ll send it to a lab to examine your pee’s chemical and other microscopic elements.
• Urine output. This test measures how much you pee over the course of 24 hours.
• Imaging tests. Your provider may order a computed tomography (CT) scan, ultrasound or other imaging tests to take a closer look at your kidneys.
• Kidney biopsy. Your provider will numb your skin and insert a needle to take a small kidney tissue sample. They’ll then send the sample to a lab for testing.

How is azotemia treated?

Azotemia treatment depends on which type you have, what’s causing it and its severity. A healthcare provider will conduct tests to determine its cause. Treatment options may include:

• IV fluids (fluids given intravenously, or through your vein) to treat dehydration.
• Medications, including diuretics (medications that make you pee), adrenergic drugs (drugs that have a similar effect as epinephrine), corticosteroids and plasma volume expanders (drugs that help replace blood plasma when you lose a lot of blood).
• Ureteral stents to allow pee to flow from your kidneys to your bladder.
• Dialysisto remove waste products from your blood.

Can azotemia be prevented?

The following tips can help you take care of your kidneys and prevent azotemia:

• Use certain medications sparingly. Some medications can damage your kidneys if you take them too often, including nonsteroidal anti-inflammatory drugs (NSAIDs), some antibiotics (penicillin, sulfonamides) and herbal supplements. Talk to a healthcare provider about what a safe dose is for you.
• Treat blood loss. A decrease in blood flow to your kidneys can cause prerenal azotemia. Make sure you apply pressure to and bandage any wounds. For a serious injury, seek medical attention.
• Get screened for kidney disease. If you have a biological family history of kidney disease, it’s a good idea to have a healthcare provider assess your risk.
• Prevent dehydration. Most adults need to drink about eight glasses of water per day. Your pee should be clear or pale yellow. If it’s darker than that, you should drink more water.
• Drink alcohol in moderation. Alcohol can damage your kidneys and affect how well they filter your blood. It can also cause dehydration. Women and people AFAB should limit their intake to one drink or less. Men and people AMAB should limit your intake to two drinks or less.
• Follow a diet that’s healthy for you. Eat lots of fruits, vegetables and whole grains. Limit the amount of salt you eat. You’re at a greater risk of developing stones if you eat a lot of salt (sodium).
• Exercise regularly. You should exercise for at least 30 minutes five to seven days per week.
• Quit smoking. Smoking damages blood vessels, which can affect blood flow to your kidneys.

What can I expect if I have azotemia?

With early diagnosis and treatment, the outlook for many people who have azotemia is good.

However, without treatment, azotemia increases your chances of developing other severe medical conditions, including chronic kidney disease. It can also cause death. Follow your healthcare provider’s treatment plan to reduce your chances of developing these or other conditions.

How do I take care of myself?

A healthcare provider will work with you to develop a treatment plan, which may include medications, changes to your lifestyle or a procedure. This may also include using medications sparingly, preventing dehydration and regular exercise.

When should I see a healthcare provider?

If a healthcare provider diagnoses you with azotemia, schedule regular follow-up appointments. You should also schedule a visit if you notice changes in your symptoms or new pain.

When should I go to the ER?

Go to the emergency room if you notice symptoms of acute kidney failure. Symptoms may include:

• Not peeing a lot.
• Swelling, especially in your ankles and feet.
• A metallic taste in your mouth.
• Fatigue.
• Nausea and vomiting.
• Diarrhea.
• Abdominal pain.
• Seizures.
• Coma.

What questions should I ask a healthcare provider?

• How do you know I have azotemia?
• If I don’t have azotemia, what other condition do I have?
• What tests will you order to diagnose azotemia?
• What type of azotemia do I have?
• What treatment do you recommend?
• What are the risks or side effects of your recommended treatment option?
• What follow-up care do I need after treatment?
• Is there permanent damage to my kidneys?
• Can you refer me to a nephrologist?

A note from Cleveland Clinic

Azotemia is a common condition that occurs when you have too many waste products in your blood. It develops after an injury or disease damages your kidneys and they’re not able to work as they should.

You may not realize you have azotemia because it often doesn’t cause any symptoms. It can be shocking to learn you have it. But healthcare workers will order tests to determine its cause and provide the best possible treatment. Talk to your providers about any questions or concerns you may have. They can answer your questions and provide support and advice on how you can best treat azotemia and take care of your kidneys.