Perinephric abscess

Background

  • An abscess of the perinephric fat that abuts the renal cortex
  • Can arise as a complication either a pre-existing pyelonephritis (majority) or from hematogenous seeding

Causative Organisms[1]

Perinephric vs renal abscess

Perinephric Renal
Necrotic Area perinephric fat between the renal cortex and Gerota's fascia renal parenchyma
Cause Pyelonephritis (majority) Pyelonephritis (vast majority)
Risk of morbidity Higher Lower

Clinical Features

  • Sign/symptoms similar to pyelo (fever, CVAT, dysuria)
  • Occurs in setting of ascending infection with obstructed pyelo

Differential Diagnosis

Dysuria

Evaluation

Laboratory Testing

  • CBC - Although it is a non-specific finding, a leukocytosis is typically seen.
  • Chemistry Panel - Lactic acidosis is a common finding and is seen earlier in the disease course in diabetic patients. Renal insufficiency is also commonly seen as well.
  • Urinalysis - Will often show evidence of pyelonephritis, however if the perinephric abscess is secondary to hematogenous spread, the urine could be sterile. Therefore a negative U/A does NOT rule out a perinephric abscess.
  • Blood and urine cultures

Imaging

  • CT
    • Imaging modality of choice
    • Sensitivity ~90%.
  • Renal ultrasound - A fluid filled mass extending from the renal cortex into the perinephric fat can be seen.

Management

Disposition

  • Admission

See Also

External Links

References

  1. Liu XQ, et al. Renal and perinephric abscesses in West China Hospital: 10-year retrospective-descriptive study. World Journal of Nephrology. 2016 Jan;5(1):108-14.