What could be causing my sudden testicular atrophy and yellow semen over the past year, given my low testosterone levels and elevated Follicle-Stimulating Hormone (FSH) levels?

Sudden Testicular Atrophy with Yellow Semen: Diagnostic Approach

Your sudden testicular atrophy over the past year with elevated FSH most likely represents primary testicular failure (hypergonadotropic hypogonadism), and the yellow semen is typically benign and unrelated to the atrophy. 1

Understanding Your Condition

Your combination of low testosterone and elevated FSH indicates primary hypogonadism - meaning your testicles themselves are failing rather than a problem with your brain's hormone signals. 1 The elevated FSH represents your pituitary gland's attempt to compensate for reduced testicular function by producing more stimulating hormone. 2

What Causes Sudden Testicular Atrophy

The most common causes of sudden-onset primary testicular failure include:

Infectious/Inflammatory Causes:

• Viral orchitis (mumps, COVID-19) causing direct testicular damage 1
• Bacterial epididymo-orchitis with secondary testicular injury 1

Vascular Events:

• Testicular torsion (even partial/intermittent) causing ischemic damage 1
• Testicular infarction from vascular compromise 1

Toxic/Medication-Induced:

• Anabolic steroids or testosterone use - this is critical to exclude, as exogenous testosterone completely suppresses spermatogenesis and causes testicular atrophy that takes 14-38 months to recover after cessation 3
• Opioid medications causing secondary suppression 1
• Chemotherapy or radiation exposure 1

Autoimmune:

• Autoimmune orchitis causing rapid testicular destruction 1

Systemic Disease:

• Chronic liver disease causing hormonal disruption and testicular atrophy 1
• Hemochromatosis (iron overload) affecting testicular function 1
• Sickle cell disease 1

About the Yellow Semen

Yellow semen is typically benign and unrelated to testicular atrophy. 1 Common causes include:

• Prolonged abstinence causing concentrated semen 1
• Dietary factors (high vitamin B intake, certain foods) 1
• Mild infection or inflammation 1
• Presence of urine in ejaculate 1

Yellow semen alone does not indicate serious pathology in men under 40 years. 1 However, if accompanied by pain, fever, or foul odor, infection should be excluded. 1

Essential Diagnostic Workup

Immediate Laboratory Testing:

• Complete hormonal panel: FSH, LH, total testosterone, and sex hormone-binding globulin (SHBG) to calculate free testosterone 1
• Prolactin level to exclude pituitary adenoma 1
• Complete semen analysis (two samples, 2-3 months apart after 2-7 days abstinence) to assess actual sperm production 4
• Thyroid function tests 1

Genetic Testing Indications:

• If semen analysis shows severe oligospermia (<5 million/mL) or azoospermia: karyotype analysis for Klinefelter syndrome (47,XXY) and Y-chromosome microdeletion testing 5, 4
• Chromosomal abnormalities occur in 10% of men with severe oligospermia 6

Imaging Studies:

• Scrotal ultrasound with Doppler to assess testicular volume, blood flow, masses, varicocele, and structural abnormalities 1, 6
• Testicular volumes <12 mL are definitively considered atrophic 6

Critical History Elements:

• Any use of testosterone, anabolic steroids, or performance-enhancing drugs - this is the most important reversible cause 3
• History of testicular trauma, torsion, or infection 1
• Medication history (opioids, glucocorticoids, chemotherapy) 1
• Systemic illness (liver disease, diabetes, HIV) 1
• History of cryptorchidism (undescended testicles) 1
• Occupational or environmental toxin exposures 1

Prognosis and Fertility Implications

The outlook depends on your current sperm production:

• Even with elevated FSH and testicular atrophy, 30-50% of men still have retrievable sperm for assisted reproduction 7
• FSH levels >7.6 IU/L indicate impaired spermatogenesis but not necessarily complete absence of sperm 5, 2
• Men with FSH >7.5 IU/L have 5-13 fold higher risk of abnormal semen parameters compared to men with FSH <2.8 IU/L 2

If you desire future fertility:

• Never start testosterone replacement therapy - it will completely suppress remaining sperm production through negative feedback, potentially causing azoospermia that takes months to years to recover 5, 3
• Consider sperm banking immediately if any sperm are found on semen analysis 6
• Microsurgical testicular sperm extraction (micro-TESE) offers 40-50% sperm retrieval rates even with elevated FSH for use with IVF/ICSI 5

Treatment Approach

Address Reversible Causes First:

• Stop any testosterone, anabolic steroids, or opioids immediately 1, 3
• Treat underlying infections with appropriate antibiotics 1
• Optimize metabolic health: weight loss if obese, as obesity-associated hypogonadism can be reversed 5
• Manage chronic diseases (diabetes, liver disease) 1

Fertility-Preserving Hormonal Therapy (if appropriate):

• FSH analogue treatment may improve sperm concentration and pregnancy rates in men with idiopathic infertility and FSH <12 IU/L 5, 4
• Selective estrogen receptor modulators (clomiphene) or aromatase inhibitors for low testosterone scenarios, though benefits are limited compared to assisted reproductive technology 5, 4
• Avoid testosterone monotherapy - it worsens spermatogenesis 4, 3

Monitoring:

• Repeat semen analysis every 6-12 months to detect early decline in sperm parameters 6
• Serial hormonal testing after addressing metabolic stressors 5
• Teach testicular self-examination given increased cancer risk with testicular atrophy 6

Critical Red Flags Requiring Urgent Urology Referral

• Palpable testicular mass develops 5
• Rapid progressive testicular atrophy 5
• Testicular volume <12 mL with age <30 years and history of cryptorchidism (>34% risk of intratubular germ cell neoplasia) 6
• Severe oligospermia or azoospermia confirmed on semen analysis 4

Common Pitfalls to Avoid

• Do not assume yellow semen indicates serious pathology - it is usually benign and unrelated to testicular atrophy 1
• Do not prescribe testosterone for low libido or energy if fertility is a concern - it will worsen spermatogenesis 5, 4
• Do not delay semen analysis - FSH levels alone cannot predict fertility status 4, 2
• Do not overlook anabolic steroid use - patients may not volunteer this information, but it is the most common reversible cause of sudden testicular atrophy in young men 3