| Testicular torsion | Torsion of appendage | Acute epididymitis |
Historical features |
Peak incidence | Perinatal and puberty | Prepubertal | <2 years and postpubertal |
Onset of pain | Usually sudden | Usually sudden | Usually gradual |
Duration of pain | Usually <12 hours | Usually >12 hours | Usually >24 hours |
Previous episodes | Typical | Unusual | If previous episode |
Nausea and vomiting | Common | Uncommon | Uncommon |
Fever | Unusual | Unusual | Common |
History of trauma | Occasional | Unusual | Unusual |
Dysuria or discharge | Rare | Rare | Common |
Physical findings |
Suggestive findings | Horizontal lie, high-riding testicle | Palpable nodule "blue dot" | None |
Cremasteric reflex | Usually absent | Usually present | Usually present |
Tenderness | Testicular initially, then diffuse | Appendage initially, then testis | Epididymis initially, then diffuse |
Scrotal erythema or edema | Common >12 hours | Common >12 hours | Common >12 hours |
Laboratory tests |
Pyuria | Unusual | Unusual | Common |
Positive smear, culture, rapid molecular testing, or NAAT for STD | No | No | Often |
Leukocytosis | Common | Uncommon | Common |
Imaging |
Color Doppler ultrasound¶ | Decreased blood flow, spermatic cord knot | Normal or increased | Normal or increased |