Definition of Perirenal abscess:

Perirenal abscess is a pocket of pus caused by an infection around one or both kidneys.

Causes, incidence, and risk factors:

Most perirenal abscesses are caused by urinary tract infections that start in the bladder, spread to the kidney, and then spread to the area around the kidney. Other causes of perirenal abscess include surgery in the urinary tract or reproductive system and bloodstream infection.

The biggest risk factor for perirenal abscess is kidney stones that block the flow of urine and provide a place for an infection to grow. Bacteria tend to stick to the stones and antibiotics can't kill the bacteria there.

Stones are found in 20-60% of patients with perirenal abscess. Other risk factors for perirenal abscess include:

• Diabetes
• Having an abnormal urinary tract
• Trauma