Renal abscess

Background

  • Rare clinical entity which can lead to delayed diagnosis
  • Usually a complication of a UTI or pyelonephritis
  • Less often can be due to hematogenous spread from other sources of infection
    • Most commonly due to Staph aureus

Risk Factors

Clinical Features

  • Costovertebral, flank, lumbar, lower chest, or back pain
    • Usually unilateral
  • Fever, especially if prolonged or after antibiotic initiation
  • Nausea, vomiting
  • UTI or pyelonephritis symptoms not improving with antibiotics

Differential Diagnosis

Diagnosis

  • Labs
    • CBC, BMP, UA, lactate
    • Urine culture, blood cultures
      • Some studies have shown up to 66% will have + blood cultures
  • Imaging
    • US
      • Well-defined hypoechoic lesion with thick walls and usually with internal debris
    • CT

Management

  • Antibiotics
  • Percutaneous drainage
  • Open surgical management if patient fails antibiotics/percutaneous drainage

Disposition

  • Admission for IV antibiotics and drainage
    • Especially if elderly or elevated BUN or creatinine

Complications

  • Need for open surgical management or nephrectomy
  • Renal failure
  • Sepsis, bacteremia
  • Emphysematous kidney
  • Cortical abscesses can rupture and form perinephric abscesses

References

  • Dembry LM, Andriole VT. “Renal and Perirenal Abscesses” Infectious Disease Clinics North America: 11, 3, (Sept 1997).
  • Getting GK, Shaikh N. “Renal Abscess” Journal of EM: 31, 1 (2006): 99-100.
  • Judith E, Stapczynski J. Stephan. "Urinary Tract Infections” Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. New York: McGraw-Hill, 2011. 632.
  • Yen DHT, et al. “Renal Abscess: Early Diagnosis and Treatment” Am J EM: 17, 2 (March 1999).
  • Shu T, Green JM, Orihuela E. “Renal and Perirenal Abscesses in Patients with Otherwise Anatomically Normal Urinary Tracts” Journal of Urology: 172 (July 2004): 148-150.
  • http://www.ncbi.nlm.nih.gov/pubmed/16798166