Guidelines for Evaluation and Management of Testicular Swelling in Infants

Clinical Assessment

Scrotal ultrasound with color Doppler should be obtained immediately in any infant with testicular swelling when torsion cannot be excluded clinically. The American College of Radiology recommends this as the first‑line imaging modality. [1][2]
Diffuse testicular tenderness favors torsion, whereas focal upper‑pole tenderness suggests testicular appendage torsion. This distinction aids rapid triage. [1][2]
The “blue‑dot” sign—visible infarcted appendage through the scrotal skin—is pathognomonic for appendage torsion but is present in only about one‑fifth of cases. [1][2]
Fever and urinary symptoms point toward epididymitis/orchitis, which is uncommon in children under two years of age. [1][2]

Absent or markedly reduced intratesticular blood flow on color/power Doppler is the hallmark of torsion. Sensitivity ranges from 69 % to 96.8 % and specificity from 87 % to 100 %. 4
False‑negative Doppler results can occur in infants because baseline testicular flow is physiologically low; always compare with the contralateral testis as an internal control. [4][5]
The “whirlpool sign” (twisted spermatic cord) is the most specific sonographic indicator of torsion. 5
Torsion typically shows an enlarged, heterogeneous, hypoechoic testis often accompanied by an ipsilateral hydrocele. [4][5]
Testicular appendage torsion demonstrates a focal hyperechoic lesion at the upper pole with normal overall testicular perfusion. [1][2]
Epididymitis/orchitis is characterized by increased color Doppler flow (hyperemia) and an enlarged, hypoechoic epididymis. [4][5]

Immediate surgical exploration (within 6–8 hours of symptom onset) is mandatory for confirmed or highly suspected torsion to prevent irreversible testicular loss. [1][2]
Testicular salvage rates decline with longer torsion duration and greater degree of rotation. 4

Testicular appendage torsion is self‑limited; management consists of analgesia and observation. [1][2]
For epididymitis/orchitis, evaluate for urinary tract infection or underlying urogenital anomalies; administer antibiotics when infection is confirmed and provide supportive care. [1][2][4][3]

Do not rely on a normal Doppler flow pattern to exclude torsion in infants; reduced physiologic flow can mask pathology. [4][5]
Partial torsion may retain or even increase flow; therefore, seek the whirlpool sign and compare spectral waveforms between testes. 5
Reperfusion hyperemia after spontaneous detorsion can mimic epididymitis; correlate imaging with a history of intermittent pain. 4

Torsion has a bimodal age distribution (neonatal and post‑pubertal) but can occur at any age, including one year. [1][2]
Incarcerated inguinal hernia and idiopathic scrotal edema are additional differential diagnoses unique to infancy. [1][2]

All statements are supported by evidence from the American College of Radiology (2024) as indicated by the citation IDs.