The role of ultrasound in detecting renal tract abnormalities following a single episode of epididymitis

Aim: The aim of the study was to establish the utility of ultrasound scan in detecting renal tract abnormalities following a single episode of epididymitis. Methods: A single-centre retrospective review of all boys diagnosed with epididymitis between October 2012 and 2017 including review of follow up imaging and clinical course was completed. Primary outcome was new diagnosis of renal tract abnormality by ultrasound. Main results: Eighty-four boys with a first diagnosis of epididymitis were identified. Sixty-four cases (76%) were diagnosed at scrotal exploration, the remaining twenty clinically. Median age was 7.30 years (range 0.08–15.83 years), and five had a positive urine culture at presentation. Forty-eight boys (57%) had a follow-up ultrasound scan (at median 4.57 weeks [range 1–31 weeks]). Only two renal tract abnormalities were identified by ultrasound scan, both in boys aged < 6 months, and neither was clinically relevant. Recurrent epididymitis occurred in 4 cases at median 26 days after initial presentation, of whom 3 had been followed up by ultrasound after initial presentation, all of which were normal. Further investigation revealed posterior urethral valves in 1 boy (age 6.5 months at initial presentation). Conclusion: Following a single episode of epididymitis, ultrasound was not helpful at detecting clinically relevant renal tract abnormalities, and furthermore did not identify the only patient with a clinically relevant abnormality. Based on these data, we propose follow-up imaging only in boys ≤ 6 months of age with a positive urine culture or a recurrent episode with consideration given to micturating cystogram even if ultrasound normal. Level of evidence: IV.