From the Guidelines
Unilateral testicular swelling is most commonly caused by epididymitis, testicular torsion, or torsion of the testicular appendage, and immediate medical evaluation is necessary to determine the exact cause and appropriate treatment. According to the most recent study 1, the three most common causes of acute scrotal pain, which includes unilateral testicular swelling, are torsion of a testicular appendage, epididymitis, and testicular torsion, accounting for approximately 85% to 90% of cases.
Common Causes
- Epididymitis, an inflammation of the epididymis, is often due to bacterial infection and can be diagnosed using ultrasound, which shows an enlarged and hypoechoic epididymis due to edema, as well as increased blood flow corresponding to hyperemia 1.
- Testicular torsion is a medical emergency requiring immediate surgical intervention, and ultrasound findings include an enlarged heterogeneous testis, ipsilateral hydrocele, skin thickening, and no color Doppler flow in the testis or spermatic cord 1.
- Torsion of the testicular appendage is the most common etiology in prepubertal boys, and clinical presentations such as focal tenderness over the upper pole of the testes and sudden onset of symptoms can overlap with the presentations of epididymitis and testicular torsion 1.
Diagnosis and Treatment
Diagnosis of unilateral testicular swelling should be made using a combination of clinical history, physical examination, and ultrasound imaging, which is the established first-line imaging modality for acute scrotal disease 1. Treatment typically involves antibiotics for epididymitis, immediate surgical intervention for testicular torsion, and supportive care for torsion of the testicular appendage. Prompt medical attention is crucial to prevent potential complications such as infertility or tissue death, and self-examination and awareness of testicular health can aid in early detection of issues.
From the Research
Causes of Unilateral Testicular Swelling
- Infections such as epididymitis and epididymo-orchitis, which can be caused by bacteria like Neisseria gonorrhoeae, Chlamydia trachomatis, or enteric bacteria 2
- Testicular torsion, a urologic emergency that requires rapid surgical exploration and orchidopexy to reduce the risk of testicular loss due to ischemia 2, 3
- Testicular cancer, which commonly manifests as a painless, incidentally discovered mass in a single testis 2
- Varicocele, a benign mass that can be associated with impaired fertility due to increased scrotal temperature, testicular hyperthermia, oxidative stress, and reduced spermatogenesis 2
- Hydrocele, a benign mass that can cause scrotal swelling, and in some cases, can be a "tension hydrocele" that compromises testicular perfusion 4
- Scrotal lymphangioma, a rare cause of scrotal swelling that can present with painful scrotal swelling and complex multicystic structure on ultrasound 5
- Intermittent testicular torsion, a condition characterized by recurrent scrotal pain, abnormal testicular lie, and resolution of symptoms following bilateral orchidopexy 6
Diagnostic Methods
- Scrotal ultrasound, a quick, noninvasive, and accurate method to diagnose scrotal pathological conditions, including testicular torsion, epididymitis, and hydrocele 3, 4
- Doppler ultrasonography, used to assess vascular flow and guide triage of patients who require urgent intervention 4
Management
- Antibiotics and supportive measures for epididymitis and epididymo-orchitis 2
- Surgical exploration and orchidopexy for testicular torsion 2, 3
- Radical inguinal orchiectomy for suspected malignant testicular tumor 2
- Surgical excision for scrotal lymphangioma 5
- Bilateral orchidopexy for intermittent testicular torsion 6