Can Asymptomatic Infection Cause Testicular Atrophy?
Yes, asymptomatic infections can cause testicular atrophy, though the mechanism and likelihood vary by pathogen. The most well-documented example is mumps orchitis, which can progress to testicular atrophy and sterility even when initial symptoms are mild or subclinical, and certain sexually transmitted infections like chlamydia can cause asymptomatic epididymitis that may lead to complications 1, 2.
Viral Infections and Testicular Atrophy
Mumps represents the clearest evidence that infection can cause testicular atrophy:
- Mumps orchitis occurs in 5-37% of post-pubertal males with mumps infection, with bilateral involvement in 16-65% of cases 2
- The most critical danger is testicular atrophy leading to sterility, which can occur even after seemingly mild infections 2
- Zika virus has been shown to cause progressive testicular atrophy in animal models, with persistent viral replication in Leydig cells and reduction in serum testosterone, suggesting male fertility can be affected long-term 3
Sexually Transmitted Infections and Asymptomatic Presentation
Chlamydia and gonorrhea frequently present asymptomatically in men but can still cause complications:
- Sexually transmitted epididymitis is usually accompanied by urethritis, which is often asymptomatic 1
- Men can be asymptomatically infected with chlamydia and other STDs while still harboring active infection 1
- The sensitivity of detecting asymptomatic chlamydial infection in males has varied from 46-100% depending on testing method 1
However, the direct link between asymptomatic STI and testicular atrophy is not well-established in the provided guidelines. The CDC guidelines emphasize that epididymitis treatment aims to achieve microbiologic cure, improvement of symptoms, prevention of transmission, and decrease in potential complications including infertility or chronic pain, but do not specifically quantify the risk of testicular atrophy from untreated asymptomatic infection 1.
Other Causes of Testicular Atrophy to Consider
Non-infectious causes are more commonly documented:
- Surgical trauma from inguinal hernioplasty causes testicular atrophy through thrombosis of spermatic cord veins, not infection 4, 5
- Idiopathic lymphocytic orchitis can manifest as testicular pain and atrophy, though this is rarely reported 6
- Varicocele, testicular torsion, and primary testicular dysfunction are more common causes of atrophy 1, 7
Clinical Implications and Screening Recommendations
For sexually active men at risk:
- The USPSTF recommends screening for chlamydia and gonorrhea in sexually active men who have sex with men, given median prevalence rates of 16% for gonorrhea and 12% for chlamydia in this population 1
- Treatment of sex partners is critical—all partners within 60 days for asymptomatic infections should be evaluated and treated 1
- Retesting 3 months after treatment is recommended due to high reinfection rates 1
Important Caveats
The evidence has significant limitations:
- Most guidelines focus on symptomatic disease and partner notification rather than long-term sequelae of truly asymptomatic infection 1
- The distinction between "asymptomatic" and "unrecognized mild symptoms" is often unclear in clinical practice 1
- Testicular atrophy from infection appears more strongly associated with clinically apparent orchitis (mumps, Zika) rather than isolated asymptomatic urethritis or epididymitis 3, 2
Bottom line: While asymptomatic infections—particularly viral orchitis and potentially untreated STIs—can theoretically progress to testicular complications, the strongest evidence exists for mumps causing atrophy even after mild infection 2. For STIs, the emphasis should be on screening high-risk populations and treating asymptomatic infections to prevent transmission and potential complications, though direct evidence linking asymptomatic chlamydia/gonorrhea to testicular atrophy is limited in the provided guidelines 1.