Perirenal abscess is a pocket of pus around one or both kidneys. It is caused by an infection.
Most perirenal abscesses are caused by urinary tract infections that start in the bladder. They then spread to the kidney, and to the area around the kidney. Surgery in the urinary tract or reproductive system or a bloodstream infection can also lead to a perirenal abscess.
The biggest risk factor for a perirenal abscess is kidney stones, by blockage of urine flow. This provides a place for an infection to grow. Bacteria tend to stick to the stones and antibiotics cannot kill the bacteria there.
Stones are found in 20% to 60% of people with perirenal abscess. Other risk factors for perirenal abscess include:
- Having an abnormal urinary tract
- IV drug use
Symptoms of perirenal abscess include:
- Pain in the flank (side of the abdomen) or abdomen, which may extend to the groin or down the leg
Exams and Tests
The health care provider will examine you. You may have tenderness in the back or abdomen.
- Blood culture
- CT scan of the abdomen
- Ultrasound of the abdomen
- Urine culture
To treat perirenal abscess, the pus can be drained through a catheter that is placed through the skin or with surgery. Antibiotics should also be given, at first through a vein (IV), then can switch to pills when the infection starts improving.
In general, quick diagnosis and treatment of perirenal abscess should lead to a good outcome. Kidney stones must be treated to avoid further infections.
In rare cases, the infection can spread beyond the kidney area and into the bloodstream. This can be deadly.
If you have kidney stones, the infection may not go away.
You may need to have the infection surgically removed.
You may have to have the kidney removed if infection cannot be cleared or is recurrent. This is rare.
When to Contact a Medical Professional
Call your provider if you have a history of kidney stones and develop:
- Abdominal pain
- Burning with urination
- Urinary tract infection
If you have kidney stones, ask your provider about the best way to treat them to avoid a perirenal abscess. If you undergo urologic surgery, keep the surgical area as clean as possible.
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Schaeffer AJ, Matulewicz RS, Klumpp DJ. Infections of the urinary tract. In: Wein AJ, Kavoussi LR, Partin AW, Peters CA, eds. Campbell-Walsh Urology. 11th ed. Philadelphia, PA: Elsevier; 2016:chap 12.