Kidney (Renal) Abscess

What happens when bacteria invade a health kidney? The following information should help explain why timely evaluation and proper management are critical for best outcomes.

What is renal abscess?

An abscess is a localized collection of pus in a hollow area formed by the breaking up of tissues. A renal abscess is one that is confined to the kidney and is caused either by bacteria from an infection traveling to the kidneys through the bloodstream or by a urinary tract infection traveling to the kidney and then spreading to the kidney tissue.

A renal abscess is a very unusual disease, but generally occurs as a result of common problems such as kidney inflammation, stone disease and vesicoureteral reflux. Occasionally, a renal abscess can develop from a source of infection in any area of the body. Multiple skin abscesses and intravenous drug abuse can also be sources of renal abscess. Complicated urinary tract infections associated with stones, pregnancy, neurogenic bladder and diabetes mellitus also put a person at risk for renal abscess.

What are the symptoms of renal abscess?

The person may have fever, chills, abdominal pain, weight loss and a vague feeling of bodily discomfort. Urination may be painful and sometimes the urine is bloody. Occasionally the recognition of the disease might be delayed since the symptoms are vague and the disease is uncommon.

How is renal abscess diagnosed?

The patient often has an increased white blood cell count and bacteria often are present in the blood and urine.

X-ray findings depend on the extent and the duration of the infection. Small renal abscesses can be difficult to recognize. Ultrasounds and CT scans are most helpful in recognizing a renal abscess. CT scans appear to be the diagnostic procedure of choice with an accuracy of about 96 percent. These imaging techniques, which have been available for only two to three decades, have greatly improved the diagnostic ability for this disease.

How is renal abscess treated?

The treatment options for a renal abscess are intravenous antibiotics and drainage of the abscess by an open operation or by inserting a catheter through a needle in the skin overlying the kidney with X-ray guidance. This more recent technique, called percutaneous drainage, has become the more frequent method of drainage. Although drainage has been the traditional method of treatment, patients have been treated successfully during the past decade with intravenous antibiotics and observation when early diagnosis has been made.

What can be expected after treatment for renal abscess?

Earlier diagnoses with modern imaging techniques and less invasive treatment have produced better outcomes. However, occasionally a patient with other illnesses such as diabetes mellitus, will have advanced renal abscess that might lead to serious disease and even death. Patients treated early without much damage to the kidney should have a good outcome. It is necessary to treat the causative factors such as kidney stones, vesicoureteral reflux and other sources of infection to decrease the chances of recurrence of renal abscess.

Frequently asked question:

What can I do to prevent a renal abscess?

Prompt treatment of all urinary tract infections and bacterial infections is an important preventative measure.