How to evaluate a patient with decreased libido?

Assessment of Decreased Libido

Begin by obtaining a comprehensive sexual, medical, and psychosocial history, followed by targeted physical examination, validated screening questionnaires, and selective laboratory testing based on clinical findings—testosterone measurement is mandatory in all men with decreased libido, while additional hormonal studies depend on initial results.

History Taking

A detailed history is the cornerstone of evaluation and should systematically explore multiple domains 1:

Sexual History

• Duration and onset of decreased libido (sudden vs. gradual onset helps distinguish psychogenic from organic causes) 1
• Severity of the problem using validated instruments like the Sexual Desire Inventory-2 2
• Degree of distress associated with lack of sexual desire (essential for diagnosis) 2
• Quality of erections (spontaneous, self-stimulated, or nocturnal erections suggest psychogenic etiology if preserved) 1
• Other sexual dysfunctions: erectile dysfunction, premature ejaculation, delayed ejaculation, or orgasmic difficulties 1, 3
• Partner-related factors: vaginal dryness in female partners, partner's erectile dysfunction, relationship satisfaction 1

Medical History

• Chronic conditions: diabetes, hypertension, cardiovascular disease, depression, anxiety, chronic stress 1
• Endocrine disorders: symptoms of hypogonadism (reduced energy, reduced endurance, diminished work/physical performance, fatigue) 1
• Hyperprolactinemia symptoms: visual field changes (bitemporal hemianopsia), anosmia 1
• Cancer treatment history: chemotherapy, pelvic radiation, surgery for rectal/cervical cancers 1
• Other conditions: HIV, chronic narcotic use, pituitary disorders, chronic corticosteroid use 1

Medication Review

Critical medications associated with decreased libido include 1:

• Antidepressants: tricyclics, selective serotonin reuptake inhibitors 1
• Antihypertensives: β-blockers, vasodilators, central sympathomimetics, ganglion blockers, diuretics, ACE inhibitors 1
• Hormonal agents: tamoxifen, aromatase inhibitors (cause vasomotor symptoms, sleep disturbance, vaginal dryness, mood changes) 1
• Other: tranquilizers, alcohol, marijuana, cocaine, recreational or body-building drugs 1

Psychosocial Assessment

• Psychiatric conditions: generalized anxiety, depressive illness, psychosis, body dysmorphic disorder, gender identity problems, alcoholism 1
• Relationship factors: problems or changes in relationship, marital conflicts, major life events 1, 4
• Domestic and dyadic disturbances (particularly relevant in primary reduced libido) 3

Physical Examination

Conduct a targeted examination focusing on signs of hypogonadism and cardiovascular risk 1:

• General assessment: body habitus, body mass index or waist circumference 1
• Virilization status: body hair patterns and amounts in androgen-dependent areas 1
• Breast examination: gynecomastia 1
• Genital examination: testicular size, consistency, masses, presence of varicocele, penile abnormalities (fibrosis, retractable foreskin) 1
• Prostate examination: size and morphology 1
• Cardiovascular assessment: blood pressure, fundal arterial changes, cardiac auscultation, carotid bruits, femoral and pedal pulses 1

Note: A history of decreased libido and/or testicular atrophy on physical examination cannot reliably predict hypogonadism, making laboratory testing essential 5.

Validated Screening Questionnaires

Use structured instruments to quantify severity and facilitate discussion 1, 2:

• Sexual Desire Inventory-2: initiates discussion and assesses libido 2
• Brief Sexual Symptom Checklist for Women: includes question about desire to discuss sexual function with healthcare professional 1
• International Index of Erectile Function (IIEF): covers 5 domains including sexual desire (refers to past 4 weeks) 1
• Sexual Health Inventory for Men (SHIM): addresses sexual activity over past 6 months 1

Important caveat: Screening questionnaires should not replace full patient evaluation and laboratory testing; they have variable specificity and sensitivity 1.

Laboratory Testing

Mandatory Initial Testing

Measure total testosterone in all men with decreased libido 1, 5:

• Timing: Morning measurement preferred 1
• Free testosterone or androgen index is preferred over total testosterone alone and prevents unnecessary endocrine investigation in up to 50% of men with low total testosterone 1, 5
• Repeat if abnormal: Confirm with second measurement 1

Additional Hormonal Studies

If testosterone is low 1:

• Luteinizing hormone (LH): Measure to establish etiology of testosterone deficiency 1
  • Low or low-normal LH with low testosterone suggests central hypogonadism 1
• Prolactin: Mandatory if testosterone low with low/normal LH, or if loss of libido present 1
  • Repeat if elevated to exclude spurious result 1
  • Persistently elevated prolactin requires endocrinology referral for possible prolactinoma 1
• Pituitary MRI: For men with total testosterone <150 ng/dL combined with low/normal LH, regardless of prolactin levels (to identify non-secreting adenomas) 1

Prolactin measurement is necessary only in patients with hypogonadism and/or history of decreased libido 5.

Baseline Metabolic Testing

• Fasting glucose or HbA1c: Screen for diabetes 1
• Lipid profile: Assess cardiovascular risk 1
• Complete blood count: Rule out anemia, hematologic abnormalities 1

Selective Testing Based on Clinical Suspicion

• Estradiol: Only if breast symptoms or gynecomastia present prior to testosterone therapy 1
• Creatinine and electrolytes: If renal impairment suspected 1
• Liver function tests: If liver disorder suspected 1
• Thyroid function: If clinically indicated 1

Distinguishing Primary vs. Secondary Reduced Libido

This distinction guides treatment approach 3:

Primary Reduced Libido (Not Associated with Underlying Conditions)

• Higher educational level 3
• More disturbances in domestic and dyadic relationships 3
• Overall healthier metabolic profile (lower glycemia, triglycerides) 3
• Lower cardiovascular risk 3

Secondary Reduced Libido (Associated with Underlying Conditions)

• Hypogonadism: substantially increases reduced libido prevalence 3
• Psychopathology: nearly doubles prevalence 3
• Hyperprolactinemia: universally present 3
• Features reflect underlying conditions 3

Common Pitfalls to Avoid

• Do not rely on history alone: Decreased libido by questionnaire and testicular atrophy cannot predict hypogonadism—laboratory confirmation is essential 5
• Do not skip testosterone measurement: Even in absence of classic symptoms, measure testosterone in high-risk patients (diabetes, HIV, chronic narcotics, chemotherapy, pelvic radiation, infertility, pituitary disorders, chronic corticosteroids) 1
• Do not measure prolactin routinely: Only indicated with low testosterone plus low/normal LH, or with loss of libido 1, 5
• Do not overlook medication review: Many commonly prescribed drugs cause decreased libido and should be optimized when possible 1
• Do not ignore partner evaluation: Interview with partner confirms problem and may reveal other causes (e.g., vaginal dryness, partner erectile dysfunction) 1
• Do not forget cardiovascular assessment: Organic sexual dysfunction identifies increased cardiovascular risk requiring evaluation 1