AUA Summit - What is Kidney (Renal) Abscess?


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What is Kidney (Renal) Abscess?

An abscess is a pocket of pus in a hollow area of the body. A renal abscess is one that’s in the kidney.

Dealing with this problem quickly and properly is critical for the best results.

What are Kidneys?

The urinary tract is the body’s drainage system. It includes two kidneys, two ureters, a bladder, and a urethra.

Healthy kidneys work day and night to clean our blood. These 2 bean-shaped organs are found near the middle of the back, just below the ribs. One kidney sits on each side of the spine.

Our kidneys are our body’s main filter. They clean about 150 quarts of blood daily. Every day, they form about 1-2 quarts of urine by pulling extra water and waste from the blood. Urine normally travels from the kidneys down to the bladder and out through the urethra.

As a filter, the kidney controls many things to keep us healthy:

  • Fluid balance
  • Electrolyte levels (e.g., sodium, potassium, calcium, magnesium, acid)
  • Waste removal in the form of urine
  • The regulation of blood pressure and red blood cell counts

When the kidneys are damaged, they may not function well. In most cases, some damage won’t cause too many problems. But, major damage may require more treatment, like dialysis.


Some symptoms of a renal abscess are:

  • Fever
  • Chills
  • Pain in the belly
  • Weight loss
  • Vague feeling of bodily discomfort

You might also have pain when passing urine and the urine may be bloody.


A renal abscess can be caused by bacteria from an infection that’s gotten to the kidneys. The bacteria can travel through the blood or in urine backing up into the kidney. In the kidney, the bacteria can spread to the kidney tissue.

A renal abscess is not a common disease. It often occurs as a result of common problems such as:

A renal abscess can sometimes form from infection in other parts of the body. Abscesses in the skin and intravenous drug abuse can also lead to renal abscess.

Complicated urinary tract infections can also put a person at risk for renal abscess if linked to:

You can help prevent renal abscess by having any bacterial or urinary tract infections (UTI) treated right away.


It can sometimes take a while to notice a renal abscess. This is because the symptoms are vague and the disease isn’t common.

Lab Tests

A blood test may show a higher white blood cell count and bacteria. Bacteria are often found in the urine as well.

Imaging Tests

X-ray findings depend on how bad the infection is and how long it’s been there. Small renal abscesses can be hard to notice on an x-ray.

Ultrasound and computerized tomography (CT) scans are most helpful in recognizing a renal abscess. Ultrasound uses sound waves bouncing off organs in the body to make a picture of what’s inside. A CT scan takes many x-rays which are put together by a computer to show “slices” of parts of the body. CT scans are used more often for finding renal abscess. This can find a renal abscess about 96 times out of 100.


Renal abscess is treated with antibiotics given through the blood by IV (“intravenously”) and/or by draining the pus from the abscess.

The draining can be done with surgery or by putting a tube (“catheter”) through a needle in the skin over the kidney (“percutaneous drainage”). X-rays are used to help see that the needle is in the kidney. Percutaneous drainage is a recent technique and is the method being used more often.

Drainage has been the traditional treatment for renal abscess. But during the past 10 years treating with IV antibiotics and observation has worked well when the disease has been noticed early.

After Treatment

When imaging finds this disease early, recovery is common. Also, less invasive treatment makes recovery easier. Patients treated early without much damage to the kidney should have a good outcome.

When a patient with other illnesses, like diabetes mellitus, has advanced renal abscess, it can’t easily be treated. This might lead to serious disease and even death.

The factors that caused the abscess need to be treated to lower the chances of a renal abscess forming again. Some of these factors are:

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