{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T14:01:44Z","timestamp":1790863304635,"version":"4.1.0"},"reference-count":9,"publisher":"BMJ","issue":"10","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2026,9,17]]},"published-print":{"date-parts":[[2026,10]]},"abstract":"<jats:p>A woman in her late 40s presented with abdominal sepsis secondary to emphysematous pyelitis complicated by a retroperitoneal urinoma. Despite initial antimicrobial therapy, percutaneous drainage and ureteric stenting, she developed persistent thigh pain and a posterior knee sinus. Repeat cross-sectional imaging demonstrated caudal spread of infected retroperitoneal fluid and gas along the iliopsoas and fascial planes into the thigh. Subsequent imaging identified a fistulous communication involving the colon. The exact sequence of fistula formation could not be determined, and causation between the urinary pathology and colonic communication remains uncertain. Management required multidisciplinary input, broad-spectrum antimicrobial therapy, urinary decompression, radiological drainage, bowel diversion and repeated surgical debridement. The patient recovered with resolution of sepsis and restoration of mobility. This case highlights the importance of recognising atypical limb symptoms in retroperitoneal infection and repeating imaging when clinical progress is not as expected.<\/jats:p>","DOI":"10.1136\/bcr-2025-271084","type":"journal-article","created":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T13:25:23Z","timestamp":1790861123000},"page":"e271084","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Retroperitoneal urinoma presenting as a posterior knee sinus following emphysematous pyelitis"],"prefix":"10.1136","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-3822-4752","authenticated-orcid":false,"given":"Ibrahim","family":"Alshahwani","sequence":"first","affiliation":[{"name":"Orthopedic, Southern Health and Social Care Trust, Portadown, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin G","family":"Connolly","sequence":"additional","affiliation":[{"name":"Trauma and Orthopaedic, Craigavon Area Hospital, Lisburn, UK"},{"name":"Craigavon Area Hospital, Portadown, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Riad","family":"Al-Harfoushi","sequence":"additional","affiliation":[{"name":"Craigavon Area Hospital, Portadown, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,10,1]]},"reference":[{"key":"2026100106251486000_19.10.e271084.1","doi-asserted-by":"publisher","DOI":"10.1001\/archinte.160.6.797"},{"key":"2026100106251486000_19.10.e271084.2","first-page":"470","article-title":"Management of urinary extravasation in patients with obstructive uropathy","volume":"169","author":"Patil","year":"2003","journal-title":"J Urol"},{"key":"2026100106251486000_19.10.e271084.3","article-title":"Retroperitoneal abscess tracking to thigh: an unusual presentation","volume":"2018","author":"Chaudhry","year":"2018","journal-title":"BMJ Case Rep"},{"key":"2026100106251486000_19.10.e271084.4","article-title":"Emphysematous pyelonephritis with perinephric extension and fistulous communication to the descending colon: a rare CT imaging diagnosis","volume":"12","author":"Gaikwad","year":"2026","journal-title":"BJR Case Rep"},{"key":"2026100106251486000_19.10.e271084.5","doi-asserted-by":"crossref","first-page":"54","DOI":"10.1038\/s41585-018-0122-x","article-title":"Diagnosis and management of urinary extravasation after high-grade renal trauma","volume":"16","author":"Keihani","year":"2019","journal-title":"Nat Rev Urol"},{"key":"2026100106251486000_19.10.e271084.6","doi-asserted-by":"publisher","DOI":"10.1001\/jama.2016.0287"},{"key":"2026100106251486000_19.10.e271084.7","unstructured":"National Institute for Health and Care Excellence . 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