SHM Converge Scientific Abstract ePoster Gallery-The Cold Abscess: A Large Retroperitoneal Abscess Masquerading as a Hematoma

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This case describes a 71-year-old woman with bilateral staghorn calculi and obesity who developed worsening left flank pain three weeks after bilateral ureteroscopy/lithotripsy and stent placement. Although she was afebrile, she had marked leukocytosis, elevated CRP, mild kidney injury, and urinalysis suggestive of infection. Initial non-contrast CT showed a 7.4 × 6.8 cm left retroperitoneal collection interpreted as a postoperative hematoma. However, repeat contrast CT 48 hours later showed interval enlargement to 9.0 × 7.2 cm without clear rim enhancement.<br /><br />Because her pain worsened and was out of proportion to a simple hematoma, clinicians suspected an occult infection despite the lack of fever or classic imaging findings. Interventional radiology drained the collection on hospital day 8 and found copious purulent material, confirming a retroperitoneal/perinephric abscess. The patient improved rapidly after drainage, and follow-up imaging one week later showed resolution.<br /><br />Cultures grew ESBL E. coli, Klebsiella pneumoniae, and Streptococcus anginosus. She was treated with a three-week course of IV meropenem.<br /><br />The case highlights that retroperitoneal or perinephric abscess can masquerade as a postoperative hematoma after ureteroscopy or lithotripsy. Absence of fever, modest procalcitonin elevation, and nondiagnostic imaging do not exclude serious infection. Clinical history and serial physical examinations were key to recognizing the evolving abscess and obtaining timely source control.

Asset Subtitle

Brian I. Wilhoit

Meta Tag

Author List Brian I. Wilhoit, Gregory Milburn, Hirotaka Kato, Rebekah B. Leach

Category Clinical Vignettes

Concept Retroperitoneal Abscess

Concept Drainage

Concept Antibiotics

Concept Ureteroscopy

Concept Lithotripsy

Distinguished Non-Finalist

Presenter Organization University of Kentucky College of Medicine

Presenting Author Brian I. Wilhoit

Track Adult

Keywords

retroperitoneal abscess

perinephric abscess

ureteroscopy

lithotripsy

staghorn calculi

postoperative hematoma

ESBL E. coli

meropenem

percutaneous drainage

kidney infection

Retroperitoneal Abscess

Drainage

Antibiotics

Ureteroscopy

Lithotripsy