Male Hypogonadism (Low Testosterone)

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Presentation :

• Decreased morning and spontaneous erections, Decreased libido, Infertility, Gynecomastia, Decreased male-pattern hair growth

Pathophysiology :

• Elevated LH and FSH values indicate primary hypogonadism. Common causes include:
  • Klinefelter syndrome (check karyotype)
  • atrophy secondary to mumps orchitis
  • autoimmune destruction
  • previous chemotherapy or pelvic irradiation
  • hemochromatosis
• Low or normal LH and FSH levels indicate secondary hypogonadism. Important causes include:
  • sleep apnea
  • hyperprolactinemia
  • hypothalamic or pituitary disorders (hemochromatosis, pituitary/hypothalamic tumor)
  • use of opioids, anabolic steroids, or glucocorticoids

Diagnostic Testing:

• Testosterone deficiency is diagnosed with two 8:00 AM total testosterone levels below the reference range.
  • If the testosterone measurement is equivocal, measure free testosterone.
• If the testosterone level is low, measure LH, FSH, and prolactin levels.
• If secondary hypogonadism is confirmed (low/normal FSH/LH), check iron studies to rule out hemochromatosis and obtain an MRI to evaluate for hypothalamic or pituitary lesions.

Treatment :

• Supplemental Testosterone
• Before initiation of testosterone replacement and during therapy, routinely monitor hematocrit (for erythrocytosis) and PSA (for prostate cancer)

Prognosis:

References: