Acute Scrotum Syndrome in Children: Ultrasound Differentiation of Testicular Torsion, Torsion of the Appendix Testis, and Epididymitis

Acute scrotum syndrome requires urgent ultrasound evaluation to exclude surgical pathology, primarily testicular torsion. The main tool for differentiation is grayscale scanning combined with blood flow assessment (color/power Doppler).

Epididymitis and Orchitis

According to sources, epididymitis/orchitis is the most common cause of acute scrotal pain in adolescent boys and adults. The epididymis is primarily affected, with secondary orchitis developing in 20–40% of cases due to contact spread of infection. Echographically, there is an indistinct focal or diffuse heterogeneity of the testis, diffusely enlarged heterogeneous testis — in the absence of a true mass. A characteristic feature is relatively increased Doppler blood flow.

Primary mumps orchitis is distinguished separately: unilateral or bilateral enlarged heterogeneous hyperemic testis, with the epididymis often intact.

Testicular Torsion and the Role of Doppler

Assessment of testicular perfusion by Doppler is a central element of differential diagnosis. Sources note the phenomenon of "torsion-detorsion" as a rare mimic of inflammatory hyperemia. Specific Doppler criteria for torsion and perfusion threshold values are not provided in the given fragments [to be clarified].

Torsion of the Appendix Testis

Differential ultrasound and Doppler criteria for torsion of the appendix testis (appendix of the testis/epididymis) are not described in the provided fragments [to be clarified].

Additional Modalities

Within the framework of multiparametric scrotal ultrasound, methods with increased sensitivity to blood flow (ultrasensitive Doppler) and contrast enhancement (CEUS) are investigated for assessing intratesticular perfusion. Clinical thresholds and application algorithms for these methods in acute scrotum in children are not specified in the provided fragments [to be clarified].