I'm a male of reproductive age with a history of sudden erectile dysfunction, low libido, and yellow semen that resolved, but now I've noticed a decrease in testicular size over the last 6 months, could I have had orchitis or mumps, what's causing my testicular atrophy?

Testicular Atrophy Following Resolved Sexual Dysfunction

You likely experienced orchitis (testicular inflammation) that has resulted in testicular atrophy and impaired testicular function, which explains both your resolved symptoms and current testicular shrinkage. The combination of sudden erectile dysfunction, low libido, yellow semen (suggesting infection/inflammation), followed by progressive testicular atrophy over 6 months strongly indicates post-inflammatory testicular damage 1.

Understanding What Likely Happened

Orchitis causes permanent testicular damage in a significant proportion of cases, leading to testicular atrophy and impaired spermatogenesis even after the acute infection resolves 1, 2. The pattern you describe—acute sexual dysfunction with yellow semen (indicating infection) followed by gradual testicular shrinkage—is classic for post-infectious orchitis 1.

Key Clinical Features Supporting Orchitis:

• Yellow semen indicates infection or inflammation of the reproductive tract, consistent with orchitis or epididymo-orchitis 1
• Sudden onset of erectile dysfunction and low libido during the acute phase suggests systemic inflammatory response affecting the hypothalamic-pituitary-gonadal axis 1
• Progressive testicular atrophy over 6 months after symptom resolution indicates irreversible damage to the seminiferous tubules from the inflammatory process 3, 1
• Asymptomatic or subclinical orchitis is common and often goes undiagnosed, but systematic histopathological analyses show high prevalence of inflammatory reactions in testicular biopsies from men with fertility problems 1

Mumps Orchitis Specifically:

While mumps orchitis is a well-known cause of testicular atrophy, it typically presents with obvious systemic symptoms (fever, parotid gland swelling) that you would have noticed 3, 2. However, other viral and bacterial infections can cause identical testicular damage without the classic mumps presentation 1.

• Mumps orchitis causes testicular atrophy in a significant proportion of bilateral cases, with atrophy developing weeks to months after the acute infection 3, 2
• Post-mumps testicular atrophy results in severely impaired testosterone production (mean production rate only 20% of normal elderly men) and elevated gonadotropins 3
• Interferon-alpha 2B treatment during acute bilateral mumps orchitis can prevent testicular atrophy, but this is only effective if given during the acute phase, not after atrophy has developed 2

Essential Immediate Actions

1. Confirm Testicular Atrophy and Assess Function:

Measure morning serum total testosterone, FSH, and LH on two separate occasions to determine the extent of testicular damage 4, 5. This hormone profile will reveal:

• Elevated FSH (>7.6 IU/L) with testicular atrophy indicates non-obstructive azoospermia or severe oligospermia from primary testicular failure 5
• Low testosterone with elevated LH and FSH confirms primary testicular failure from the orchitis 5
• Normal testosterone with elevated FSH suggests isolated damage to the seminiferous tubules with preserved Leydig cell function 3

2. Obtain Semen Analysis:

Perform at least two semen analyses separated by 2-3 months to assess the impact on sperm production 5, 6. Post-orchitis testicular atrophy commonly results in:

• Severe oligospermia or azoospermia depending on the extent of seminiferous tubule damage 1, 2
• Testicular atrophy on physical examination is characteristic of non-obstructive azoospermia 5

3. Physical Examination:

Assess testicular volume using a Prader orchidometer (normal volume 15-25 mL; volumes <12 mL indicate atrophy) and evaluate testicular consistency 5. Post-orchitis atrophy typically presents with:

• Firm, small testes due to fibrosis and loss of seminiferous tubule volume 1
• Bilateral involvement is common but asymmetric atrophy can occur 3, 2

Fertility Preservation and Treatment Options

If Sperm Are Still Present:

Immediately cryopreserve sperm if any are found on semen analysis, as progressive testicular atrophy may lead to complete azoospermia 5, 6. Banking 2-3 ejaculates provides insurance against further decline 5.

If Azoospermia Has Developed:

Microsurgical testicular sperm extraction (micro-TESE) offers 40-50% sperm retrieval rates even with elevated FSH and testicular atrophy 5. However, complete AZFa and AZFb Y-chromosome microdeletions predict near-zero sperm retrieval success, so genetic testing is mandatory before attempting TESE 5.

Genetic Testing Requirements:

• Karyotype analysis to exclude Klinefelter syndrome (47,XXY) if azoospermia or severe oligospermia (<5 million/mL) is confirmed 5, 7
• Y-chromosome microdeletion testing (AZFa, AZFb, AZFc regions) if sperm concentration is <1 million/mL 5, 7

Testosterone Replacement Considerations

If testosterone is low and you have completed fertility goals or sperm have been cryopreserved, testosterone replacement therapy normalizes libido, improves erectile function, and enhances quality of life 7. However:

• Never start testosterone therapy if current or future fertility is desired, as it completely suppresses spermatogenesis through negative feedback on the hypothalamus and pituitary, causing azoospermia that can take months to years to recover 5, 7, 6
• Testosterone deficiency may worsen after micro-TESE, requiring subsequent testosterone replacement once fertility goals are abandoned 5

Critical Pitfalls to Avoid

• Do not assume testicular atrophy means zero sperm production—up to 50% of men with non-obstructive azoospermia and elevated FSH have retrievable sperm with micro-TESE 5
• Do not delay sperm banking if any sperm are present, as progressive atrophy may eliminate this option 5, 6
• Do not start testosterone replacement without first confirming fertility status and banking sperm if desired, as testosterone will eliminate any remaining sperm production 5, 7, 6
• Chronic asymptomatic orchitis is underestimated as a cause of male infertility because noninvasive diagnostic techniques are not yet available 1

What This Means for Your Health

Men with abnormal semen parameters have higher rates of testicular cancer and increased mortality rates compared to fertile men 5. This evaluation is important for overall health screening, not just fertility 5.