The role of emergency ultrasound for evaluating acute pyelonephritis in the ED

Am J Emerg Med. 2011 Sep;29(7):721-4. doi: 10.1016/j.ajem.2010.01.047. Epub 2010 May 1.


Background: Controversy remains over the imaging method of choice for evaluating acute pyelonephritis (APN) in the emergency department (ED).

Objective: The aim of the study was to determine the efficacy of ultrasound in the diagnosis and management of patients presented to the ED with APN.

Methods: This was a retrospective study of prospectively collected data. A cohort of ED patients diagnosed as APN were prospectively registered, and their medical records were then retrospectively reviewed for the presence of complications (admitted >14 days, admission to intensive care unit, or received invasive procedures), significant abnormalities (hydronephrosis, polycystic kidney diseases, renal abscess, emphysematous pyelonephritis), and mild abnormalities (cysts, stones, swelling).

Results: The study included 243 patients. Most of the patients received one or more renal imaging studies (n = 206) and 39.5% of which were considered abnormal. The rates of significant abnormalities on different imaging methods were Kidney-ureter-bladder (KUB), 16.3%; emergency ultrasound (EUS), 39.6%; combination of KUB and EUS, 56.6%; and computed tomography, 58.8%. Factors contributed to complicated APN were elderly, male, a history of preexisting renal diseases, current use of catheters, previous renal calculi, and diabetes mellitus. Significant abnormalities can be identified by EUS in 61% of patients with complicated APN. In fact, the presence of significant sonographic abnormalities effectively diverted 34.3% of patients to receive surgical interventions (percutaneous nephrostomy, abscess aspiration, ureteroscopic stone manipulation, lithotripsy, or nephrectomy).

Conclusion: Structural abnormalities are not uncommon in ED patients with APN. Early assessment of these patients with EUS is likely to have a great impact on their diagnosis and management.

MeSH terms

  • Acute Disease
  • Adult
  • Chi-Square Distribution
  • Emergency Service, Hospital
  • Female
  • Humans
  • Kidney / diagnostic imaging
  • Kidney Diseases / diagnosis
  • Kidney Diseases / diagnostic imaging
  • Kidney Diseases / therapy
  • Male
  • Middle Aged
  • Pyelonephritis / diagnosis
  • Pyelonephritis / diagnostic imaging*
  • Pyelonephritis / therapy
  • Retrospective Studies
  • Ultrasonography