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secondary hypogonadism

Failure of adequate hypothalamic or pituitary gonadotropin stimulation. Etiology: 1) initial manifestation at the time of puberty a) generally results from isolated failure of GnRH secretion b) may be caused by structural pituitary or hypothalamic lesion c) if accompanied by anosmia -> Kallmann's syndrome 2) post-pubertal manifestation a) intracranial neoplasm 1] prolactinoma 2] craniopharyngioma b) hemochromatosis 3) ostructive sleep apnea [2,3] 4) opioids, anabolic steroids, glucocorticoids 3) hypogonadotropic hypogonadism Laboratory: 1) 8 AM serum testosterone* < 150 ng/dL (male) - MSKAP17 problem with serum testosterone 178 ng/dL [1] 2) diminished serum luteinizing hormone (serum LH) & serum follicle-stimulating hormone (serum FSH) 3) evidence of other pituitary hormone abnormalities a) serum prolactin b) serum thyroid-stimulating hormone (serum TSH) c) serum ACTH d) serum growth hormone (GH) e) serum FSH & serum LH may be inappropriately low 4) serum iron, serum ferritin & transferrin saturation if hemochromatosis suspected 5) anabolic steroids in urine * do not measure serum testosterone if patient has regular morning erections, no gynecomastia & normal genitals Special laboratory: - sleep study if suspected obstructive sleep apnea [3] Radiology: - MRI of pituitary & hypothalamus Management: - see testosterone replacement therapy - testosterone replacement therapy does not treat infertility - it impairs spermatogenesis

Related

Kallmann syndrome; hypogonadotropic hypogonadism & anosmia

Specific

hypogonadotropic hypogonadism; gonadotropin deficiency

General

hypogonadism

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 17, 19. American College of Physicians, Philadelphia 1998, 2012, 2015, 2022 - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  2. Kim SD, Cho KS Obstructive Sleep Apnea and Testosterone Deficiency. World J Mens Health. 2019 Jan;37(1):12-18. PMID: 29774669 PMCID: PMC6305865 Free PMC article
  3. NEJM Knowledge+ Endocrinology