What are the potential causes and treatments for low semen volume, hypolibidinemia (low libido), and erectile dysfunction?

Evaluation and Management of Low Semen Volume with Low Libido and Erectile Dysfunction

Begin by measuring morning total testosterone, FSH, and prolactin levels, as this triad of symptoms strongly suggests hypogonadism, which requires biochemical confirmation before treatment. 1

Initial Diagnostic Workup

Essential Laboratory Testing

• Measure morning total testosterone (before 10 AM) on two separate occasions if initial value is low, as testosterone levels fluctuate and diagnosis requires persistent deficiency 1
• Measure FSH levels to distinguish primary (elevated FSH) from secondary hypogonadism (low/normal FSH) 1
• Measure serum prolactin in all men with reduced libido and erectile dysfunction combined with low testosterone, as hyperprolactinemia can cause this exact symptom constellation 1
• Check SHBG levels if total testosterone is borderline, since elevated SHBG reduces bioavailable testosterone and can cause functional hypogonadism despite normal total testosterone 1
• Obtain fasting glucose and lipid profile to identify metabolic syndrome, diabetes, and cardiovascular risk factors that commonly coexist with and exacerbate sexual dysfunction 1, 2

Critical Physical Examination Elements

• Palpate bilaterally for vas deferens to rule out congenital bilateral absence of vas deferens (CBAVD), which presents with low semen volume 3, 4
• Assess testicular size and consistency: normal-sized testes suggest obstruction while atrophic testes indicate primary testicular failure 3, 5, 4
• Perform digital rectal examination to assess prostate size and consistency 1, 4
• Measure BMI and waist circumference as obesity decreases SHBG and is associated with functional hypogonadism 1

Semen Analysis Requirements

• Obtain at least one semen analysis with 2-3 days abstinence, examining volume, pH, and sperm parameters 5
• Check semen pH: acidic semen (pH <7.0) with low volume strongly suggests ejaculatory duct obstruction or CBAVD 4
• Perform post-ejaculatory urinalysis if semen volume is <1 mL (except in bilateral vasal agenesis or hypogonadism) to diagnose retrograde ejaculation 5, 4

Distinguishing Primary Causes Based on Hormone Patterns

Secondary Hypogonadism (Low Testosterone with Low/Normal FSH)

• This pattern indicates hypothalamic-pituitary dysfunction and is potentially reversible with appropriate treatment while preserving fertility 1
• If prolactin is elevated, obtain MRI of pituitary to evaluate for prolactinoma or other pituitary masses 1
• Review all medications for drugs that suppress the HPG axis: opiates, glucocorticoids, anabolic steroids, GnRH agonists/antagonists 1
• Assess for systemic conditions: type 2 diabetes, metabolic syndrome, chronic organ failure, HIV infection, which cause functional hypogonadism 1

Primary Hypogonadism (Low Testosterone with Elevated FSH)

• This pattern indicates testicular failure and requires testosterone replacement therapy, which will suppress spermatogenesis 1
• Fertility preservation requires sperm banking before initiating testosterone therapy if future fertility is desired 1

Hyperprolactinemia

• Treat the underlying cause: discontinue prolactin-elevating medications (antipsychotics, metoclopramide) or treat prolactinoma with dopamine agonists 1
• Hyperprolactinemia directly suppresses libido and causes erectile dysfunction independent of testosterone levels 1

Addressing Elevated SHBG

Common Causes to Investigate

• Medications: anticonvulsants, estrogens, thyroid hormone 1, 3
• Medical conditions: hyperthyroidism, hepatic disease, HIV/AIDS 1, 3
• Lifestyle factors: aging, smoking 1, 3

Management Strategy

• Treat underlying conditions first (e.g., hyperthyroidism) or discontinue SHBG-elevating medications when possible 3
• Calculate free or bioavailable testosterone using total testosterone and SHBG to determine true androgen status 1

Evaluating Low Semen Volume Specifically

Structural Causes Requiring Imaging

• Ejaculatory duct obstruction (EDO) presents with: acidic semen (pH <7.0), volume <1.4 mL, azoospermia or severe oligospermia, normal testosterone, and palpable vas deferens 4
• Order TRUS or pelvic MRI only when clinical criteria for EDO are met: do not routinely order these studies 3, 4
• Transurethral resection of ejaculatory ducts (TURED) is the definitive treatment for confirmed EDO showing dilated seminal vesicles and ejaculatory ducts on imaging 3, 4

Congenital Bilateral Absence of Vas Deferens

• CBAVD requires no medical or surgical treatment to restore ejaculatory volume; proceed directly to testicular sperm extraction (TESE) or microsurgical epididymal sperm aspiration (MESA) with ICSI for fertility 3, 4
• CFTR gene testing for the female partner is mandatory before proceeding with assisted reproduction 3, 4

Retrograde Ejaculation

• Diagnosed by finding sperm in post-ejaculatory urine when semen volume is <1 mL 5, 4
• Common causes: diabetes with autonomic neuropathy, medications (alpha-blockers, antipsychotics), prior bladder neck or prostate surgery 4

Treatment Algorithm Based on Etiology

For Secondary Hypogonadism Without Fertility Concerns

• Testosterone replacement therapy normalizes libido, improves erectile function, and enhances quality of life 1
• Avoid testosterone if fertility is desired, as it suppresses spermatogenesis and can cause azoospermia 1, 3, 4

For Secondary Hypogonadism With Fertility Concerns

• Refer to reproductive endocrinologist or urologist for gonadotropin therapy (hCG with or without FSH) or pulsatile GnRH to restore both testosterone and spermatogenesis 1
• SERMs (clomiphene) or aromatase inhibitors may be considered off-label to increase endogenous testosterone while maintaining fertility, though benefits are modest 1

For Erectile Dysfunction Management

• PDE5 inhibitors (sildenafil, tadalafil, vardenafil, avanafil) are first-line therapy and effective in 60-65% of men, including those with hypertension, diabetes, and spinal cord injury 1, 2
• Screen for cardiovascular contraindications: recent myocardial infarction (<90 days), unstable angina, NYHA Class 2+ heart failure, uncontrolled hypertension/hypotension, recent stroke (<6 months) 6
• Absolute contraindication: concurrent nitrate use (must wait 48 hours after last tadalafil dose before nitrate administration) 6
• Common adverse effects: headache (4.1%), dyspepsia (2.4%), back pain (2.4%), myalgia (1.2%) 6
• If PDE5 inhibitors fail, consider intracavernosal alprostadil injection therapy 1, 2

For Reduced Libido Specifically

• Normalize testosterone levels as the primary intervention for hypogonadism-related low libido 1
• Treat hyperprolactinemia with dopamine agonists if present 1
• Review and modify medications that reduce libido: SSRIs, antipsychotics, opiates, finasteride 1, 4
• Address psychosocial factors: relationship disturbances, depression, anxiety require referral to mental health professional with sexual health expertise 4, 7

Lifestyle and Risk Factor Modification

Modifiable Factors That Worsen Sexual Function

• Obesity: decreases testosterone and SHBG, worsens erectile function 1, 2
• Smoking: associated with reduced fertility and erectile dysfunction 4, 2
• Alcohol: reduces semen volume and sperm morphology 4
• Anabolic steroid use: must be discontinued as it suppresses endogenous testosterone production and spermatogenesis 4
• Poor diet and lack of exercise: independently associated with reduced fertility and erectile dysfunction 4, 2

Genetic Testing Before Assisted Reproduction

Mandatory Testing

• Karyotype analysis for azoospermia or severe oligospermia (<5 million/mL) 3, 5, 4
• Y-chromosome microdeletion analysis for azoospermia or sperm concentration <1 million/mL 3, 5, 4
• CFTR gene testing for female partner if male has CBAVD 3, 4
• Genetic counseling before ICSI as genetic abnormalities may be transmitted to offspring 3, 4

Critical Pitfalls to Avoid

• Never initiate testosterone replacement in men desiring fertility without first discussing permanent suppression of spermatogenesis and offering sperm banking 1, 3, 4
• Do not attribute low semen volume to stress alone; stress affects sperm motility but not semen volume 4
• Do not routinely order TRUS or pelvic MRI as part of initial evaluation—reserve for cases meeting specific clinical criteria for EDO 3, 4
• Do not prescribe PDE5 inhibitors to men taking nitrates or those with recent cardiovascular events 6, 8
• Do not delay prolactin measurement in men with the triad of low libido, erectile dysfunction, and low testosterone 1
• Do not overlook medication-induced causes: review all current medications for HPG axis suppression or sexual side effects 1, 4