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E46 Endocrinology
Male Reproductive Endocrinology
Toronto Notes 2019
Two Distinct Features of Primary Hypogonadism
• The decrease in sperm count is affected to
a greater extent than the decrease in serum
testosterone level
• Likely to be associated with gynecomastia
Two Features of Secondary Hypogonadism
• Associated with an equivalent decrease in sperm count and serum testosterone
• Less likely to be associated with gynecomastia
Hypogonadism and Infertility
• seeUrology,U35
• deficiencyingametogenesisortestosteroneproduction
Etiology
• causesincludeprimary(testicularfailure),secondary(hypothalamic-pituitaryfailure),andidiopathic • primaryhypogonadismismorecommonthansecondary
Diagnosis of Testosterone Deficiency Syndrome (aka adult onset primary hypogonadism) • requiresclinicalmanifestationsoftestosteronedeficiency(seesidebar)ANDdocumentedtestosterone
levels below local lab ranges (confirmed on x2 separate analyses, test needs to be done at 8-9am) • ruleoutsecondarycauses
Table 37. Classification and Features of Hypogonadism
Approach to Male Infertility
Infertility: failure of a couple to conceive after 12 mo of regular intercourse without use of contraception in women <35 yr of age; after 6 mo of regular intercourse without use of contraception in women ≥35 yr
History
• Partner status re: infertility
• Length of time for attempt to conceive
• Prior successes with other partners
• Ejaculation problems
• Frequency of intercourse
• Prev Surg, Med Hx, STI Hx
• Hx orchitis? Cryptorchidism?
• Hx toxic exposure?
• Medications
• Alcohol and illicit drug use
• Heat exposure: bath, sauna, whirlpool
• Smoking
P/E
• General (height, weight, gynecomastia,
masculine)
• Testicular size and consistency
• Varicocele?
• Pituitary disease?
• Thyroid disease?
Investigations
Should be considered for couples unable to conceive after 12 mo of unprotected and frequent intercourse. Consider earlier evaluation if suggestive medical Hx and physical, and in women ≥35 yr of age
• Semen analysis x 2 (sperm count,
morphology, motility)
• Scrotal/testicular U/S (look for varicocele)
• Blood work: LH, FSH, testosterone,
prolactin, thyroid function tests, DNA fragmentation of sperm, karyotype, Y chromosome deletion
• Test female partner (see Gynecology, GY23) Treatment
• No specific therapy for majority of cases
• Treat specific causes
• Consider: intrauterine insemination, IVF, therapeutic donor insemination, testicular aspiration of sperm, adoption
Diagnosis
Definition Etiology
Hypergonadotropic Hypogonadism (Primary Hypogonadism)
Primary testicular failure
 LH and FSH
 testosterone and sperm count
Congenital
Chromosomal defects (Klinefelter’s, Noonan) Cryptorchidism
Disorders of sexual development (DSD) Bilateral anorchia (vanishing testicle syndrome) Myotonic dystrophy
Mutation of FSH or LH receptor gene
Disorders of androgen synthesis
Germ cell defects
Sertoli cell only syndrome Leydig cell aplasia/failure
Infection/Inflammation
Orchitis – TB, lymphoma, mumps, leprosy Genital tract infection
Physical factors
Trauma, heat, irradiation, testicular torsion, varicocele
Drugs
Marijuana, alcohol, chemotherapy, ketoconazole, glucocorticoid, spironolactone
Testicular size and consistency (soft/firm)
Sperm count
LH, FSH, total, and/or bioavailable testosterone hCG stimulation (mainly used in pediatrics) Karyotype
Hypogonadotropic Hypogonadism (Secondary Hypogonadism)
Hypothalamic-pituitary axis failure
 LH + FSH (LH sometimes inappropriately normal)  testosterone and sperm count
Congenital
Kallman’s syndrome Prader-Willi syndrome Abnormal subunit of LH or FSH
Infection
Tuberculosis, meningitis
Endocrine
Adrenal androgen excess
Cushing’s syndrome
Hypo or hyperthyroidism
Hypothalamic-pituitary disease (tumour, hyperprolactinemia, hypopituitarism)
Drugs
Alcohol, marijuana, spironolactone, ketoconazole, GnRH agonists, androgen/estrogen/progestin use, chronic narcotic use
Chronic illness
Cirrhosis, chronic renal failure, AIDS
Sarcoidosis, Langerhan’s cell histiocytosis hemochromatosis
Critical illness
Surgery, MI, head trauma
Obesity Idiopathic
Testicular size and consistency (soft/firm)
Sperm count
LH, FSH, total, and/or bioavailable testosterone Prolactin levels (and pituitary panel - T4/8am cortisol) Fe, Transferrin
MRI of hypothalamic-pituitary region
Treatment
• goal:testosteronereplacement(improvelibido,musclemass,strength,bodyhairgrowth,bonemass) ■ IM injection, transdermal testosterone patch/gel, oral
■ side effects: acne, fluid retention, erythrocytosis, sleep apnea, benign prostatic hypertrophy,
uncertain effects on cardiac events/mortality in older men
■ contraindicated if history of metastatic prostate cancer, breast cancer, severe LUTS associated with
BPH, uncontrolled or poorly controlled CHF, PSA>4, hematocrit >50%
■ testosterone therapy only to treat symptoms of hypogonadism, often results in decreased
spermatogenesis by further suppression of hypothalamic-pituitary-gonad axis • goal: fertility
■ treat underlying cause
■ GnRH agonist if hypothalamic dysfunction with intact pituitary, administered SC in pulsatile
fashion using an external pump
■ hCG ± recombinant follicular stimulating hormone (rFSH) in cases of either hypothalamic or
pituitary lesions
■ dopamine agonist (e.g. bromocriptine, cabergoline) if prolactinoma
■ testicular sperm extraction (TESE) or microscopic sperm extraction (MICROTESE) – only if
testicular tissues are not functioning
Other Causes of Male Infertility
• hereditarydisorders:Kartagenersyndrome(primaryciliarydyskinesia),cysticfibrosis(absenceofthe vas deferens)
• anatomy:hypospadias,retrogradeejaculation
• obstruction:vasalocclusion,vasalaplasia,vasectomy,seminalvesicledisease
• sexual dysfunction: erectile dysfunction, premature ejaculation, infrequent coitus • surgery: TURP, radical prostatectomy, orchiectomy