What could cause rapid bilateral testicular atrophy in an adult male with a normal scrotal ultrasound, a subclinical left varicocele, no pain, and a normal sperm concentration (~60 million/mL)?

Rapid Bilateral Testicular Atrophy: Urgent Evaluation Beyond Varicocele

Your subclinical varicocele is not causing your rapid bilateral testicular atrophy—this requires immediate investigation for systemic causes including hypogonadotropic hypogonadism, anabolic steroid use, medication effects, or primary testicular disease.

Why Your Varicocele Is Not the Culprit

• Subclinical varicoceles do not cause testicular atrophy and should not be treated, as they are not associated with improvements in semen parameters or fertility outcomes 1, 2, 3
• Your sperm concentration of 60 million/mL is completely normal (normal is >15 million/mL), which is inconsistent with clinically significant varicocele-related testicular dysfunction 1
• Varicocele-related atrophy is typically unilateral (affecting the left side where the varicocele exists), not bilateral 4, 5
• The European Association of Urology only recommends treating varicoceles when there is a persistent testicular size difference >2 mL or 20% confirmed on two visits 6 months apart, and this applies to clinical (palpable) varicoceles, not subclinical ones 1

Critical Differential Diagnoses to Investigate Immediately

You need urgent hormonal and systemic evaluation for:

• Hypogonadotropic hypogonadism: Check serum testosterone (total and free), LH, FSH, and prolactin 1
• Exogenous testosterone or anabolic steroid use: Even if denied, this is the most common cause of rapid bilateral testicular atrophy with preserved sperm counts initially
• Medication-induced atrophy: Opioids, glucocorticoids, GnRH agonists/antagonists, or 5-alpha reductase inhibitors
• Primary testicular disease: Klinefelter syndrome (obtain karyotype if sperm count drops below 5 million/mL) 1, testicular tumors, or infiltrative diseases
• Systemic illness: Chronic liver disease, chronic kidney disease, or severe malnutrition

Specific Hormonal Evaluation Required

• FSH levels are the key marker: Normal FSH (<7.6 IU/L) with bilateral atrophy suggests secondary (central) hypogonadism, while elevated FSH suggests primary testicular failure 1
• Testosterone levels: Low testosterone with low/normal LH and FSH indicates hypogonadotropic hypogonadism
• If FSH is elevated (>7.6 IU/L), this indicates spermatogenic failure independent of your varicocele 1

Common Pitfalls to Avoid

• Do not attribute bilateral atrophy to a unilateral subclinical varicocele—this is a diagnostic error that will delay finding the true cause 1, 3
• Do not pursue varicocele repair for your subclinical varicocele, as guidelines explicitly discourage treatment of non-palpable varicoceles regardless of ultrasound findings 1, 2, 3
• Do not assume normal ultrasound excludes all pathology—many causes of testicular atrophy (hormonal, medication-induced) will not show structural abnormalities on ultrasound
• The absence of pain is irrelevant—most causes of testicular atrophy are painless 1, 2

Immediate Action Plan

1. Obtain comprehensive hormonal panel: Total testosterone, free testosterone, LH, FSH, prolactin, SHBG (morning fasting sample) 1
2. Detailed medication and supplement history: Specifically ask about testosterone, anabolic steroids, prohormones, opioids, and bodybuilding supplements
3. Serial testicular volume measurements: Use ultrasound or orchidometer to objectively document rate of atrophy over 3-6 months 4, 5
4. Repeat semen analysis in 3 months: Monitor for declining parameters that would indicate progressive testicular dysfunction 1
5. Consider endocrinology referral if hormonal abnormalities are identified

The rapid bilateral nature of your atrophy, combined with normal sperm count and only a subclinical varicocele, strongly suggests a systemic hormonal or medication-related cause rather than a local scrotal pathology 1, 5.