Management of Hypogonadism with Normal FSH and LH Levels
For patients with low testosterone (100 ng/dL) and normal FSH and LH levels, testosterone replacement therapy is the recommended first-line treatment to restore testosterone levels and alleviate symptoms. 1
Diagnostic Confirmation
- Confirm the diagnosis of hypogonadism with a second morning total testosterone measurement, as a single low reading is insufficient for diagnosis 1
- Ensure symptoms consistent with testosterone deficiency are present (reduced energy, diminished physical performance, fatigue, depression, reduced motivation, poor concentration, impaired memory, reduced sex drive, erectile dysfunction) 1
- Normal FSH and LH with low testosterone indicates secondary (hypogonadotropic) hypogonadism, suggesting a hypothalamic-pituitary issue rather than primary testicular failure 1
Additional Evaluation
- Measure serum prolactin levels to screen for hyperprolactinemia, which is particularly important in secondary hypogonadism 1
- Consider pituitary MRI if total testosterone is <150 ng/dL with low/normal LH levels, as non-secreting adenomas may be present 1
- Evaluate for conditions that may cause secondary hypogonadism: obesity, diabetes, pituitary dysfunction, HIV/AIDS, chronic narcotic use, chronic corticosteroid use 1
- Measure serum estradiol if breast symptoms or gynecomastia are present 1
Treatment Approach
- For patients not concerned with fertility: Testosterone replacement therapy to achieve levels in the mid-normal range 2
- For patients wishing to preserve fertility: Consider gonadotropin therapy (combination of hCG and FSH) rather than testosterone therapy 1, 3
- Selective estrogen receptor modulators may be considered for patients with low/normal LH who wish to preserve fertility 1
Testosterone Therapy Options
- Intramuscular testosterone enanthate: 50-400 mg every 2-4 weeks 2
- Aim for testosterone levels in the mid-normal range during treatment 1
- Choice of formulation should consider pharmacokinetics, treatment burden, and cost 1
- Short-acting testosterone preparations may have less suppression of FSH and LH compared to longer-acting formulations, which may be important if fertility is a concern 4
Contraindications to Testosterone Therapy
- Patients planning fertility in the near term 5
- Breast or prostate cancer 5
- Palpable prostate nodule or induration 5
- PSA >4 ng/mL or >3 ng/mL in high-risk patients 5
- Elevated hematocrit 5
- Untreated severe obstructive sleep apnea 5
- Severe lower urinary tract symptoms 5
- Uncontrolled heart failure, recent MI or stroke 5
Monitoring
- Evaluate symptoms, adverse effects, and compliance 5
- Measure serum testosterone and hematocrit levels 5
- Evaluate prostate cancer risk during the first year of therapy 5
- Monitor for gynecomastia, which can occur due to increased estradiol from testosterone aromatization 3
Lifestyle Modifications
- Weight loss through low-calorie diets can improve testosterone levels in obese patients with secondary hypogonadism 1
- Regular physical activity shows similar benefits, though testosterone increases are typically modest (1-2 nmol/L) 1
- Consider combining lifestyle modifications with testosterone therapy for better outcomes in symptomatic patients 1