Could an asymptomatic STI be causing my testicular atrophy despite normal USS and sperm count?

Testicular Atrophy: Asymptomatic STIs Are Not the Cause

An asymptomatic STI is not causing your testicular atrophy, especially given your normal ultrasound and normal sperm count. STIs like chlamydia and gonorrhea do not cause testicular atrophy—they cause acute symptomatic conditions (epididymitis, orchitis) that you would notice, or they cause complications in women (pelvic inflammatory disease), not silent testicular shrinkage in men 1.

Why STIs Are Not Your Problem

STIs Don't Cause Silent Testicular Atrophy

• Chlamydia and gonorrhea cause acute, symptomatic infections in men—urethral discharge, dysuria, or painful testicular swelling from epididymo-orchitis—not gradual, asymptomatic testicular atrophy 1, 2.
• The major complications of untreated chlamydia and gonorrhea occur in women (pelvic inflammatory disease, infertility, ectopic pregnancy), not men with asymptomatic infection 1.
• Your normal ultrasound rules out acute inflammatory changes that would be present with active or recent infection causing testicular damage 3.
• Approximately 70% of chlamydia and trichomoniasis infections and 53-100% of extragenital gonorrhea/chlamydia are asymptomatic, but these asymptomatic infections don't cause testicular atrophy—they remain localized to mucosal surfaces 2.

Your Normal Test Results Are Reassuring

• Normal sperm count indicates preserved spermatogenesis, which would be impaired if you had significant testicular damage from any cause 1, 3.
• Normal ultrasound with homogeneous testicular architecture and normal vascularity indicates no structural damage from infection, infarction, or other pathology 3, 4.
• A slightly smaller testis with normal ultrasound structure and normal sperm production does not indicate pathology and should be reassuring rather than alarming 4.

What Actually Causes Testicular Atrophy

Common Etiologies to Consider

• Varicocele is the most common correctable cause of male infertility and can cause progressive testicular atrophy, though you mention yours is mild and unlikely the primary cause 1.
• Hormonal abnormalities, particularly elevated FSH (>7.6 IU/L) combined with testicular atrophy, indicate primary testicular failure and spermatogenic dysfunction 3, 4.
• Genetic conditions including Klinefelter syndrome (47,XXY), Y-chromosome microdeletions, or other chromosomal abnormalities are common causes of testicular atrophy with impaired spermatogenesis 3.
• Prior testicular trauma, torsion, or surgical complications (such as inguinal hernia repair) can cause testicular atrophy through vascular compromise 5.
• Cryptorchidism history (undescended testicle), even if corrected, commonly results in smaller testicular volume but often preserves fertility 4.

What You Should Do Next

Essential Workup for Testicular Atrophy

• Obtain hormonal evaluation: Measure serum FSH and testosterone levels—elevated FSH (>7.6 IU/L) with atrophy indicates spermatogenic failure, while low testosterone suggests hypogonadism 1, 3.
• Complete two properly performed semen analyses at least one month apart with 2-3 days abstinence before collection to definitively assess fertility status 1, 4.
• Consider genetic testing if you have severe oligospermia (<5-10 million/mL) or elevated FSH: karyotype and Y-chromosome microdeletion analysis should be offered 1, 3.
• Review your medical history for cryptorchidism, prior testicular trauma, mumps orchitis, chemotherapy, radiation, or inguinal/scrotal surgery 3, 5.

STI Testing (If You Insist)

• If you remain concerned about STIs despite the evidence against them as a cause, get tested with nucleic acid amplification tests (NAATs) for chlamydia and gonorrhea from urine or urethral swab, plus syphilis serology and HIV testing 6, 2.
• Testing should be performed regardless of symptoms if you have risk factors: age <25 years, new or multiple partners, inconsistent condom use, or MSM status 1, 7.
• A negative STI screen will definitively rule out this concern and allow you to focus on the actual causes of testicular atrophy 6, 2.

Critical Pitfalls to Avoid

• Don't assume normal sperm count means everything is fine—you can have unilateral atrophy with compensatory function from the other testicle, but you should still investigate the cause 4.
• Don't ignore testicular atrophy even with normal fertility—atrophic testes (<12 mL) are a risk factor for testicular cancer and require monitoring with regular self-examination 3.
• Don't delay hormonal evaluation—if FSH is elevated, this indicates irreversible testicular damage and you need counseling about fertility preservation options 3, 4.
• Don't confuse asymptomatic STI carriage with testicular pathology—asymptomatic infections remain mucosal and don't invade testicular tissue to cause atrophy 2, 8.