Male hypogonadism/Androgens Flashcards
Tests have 2 major functions…
1) testosterone produced by leydig cells, under control of LH
2) sperm production by seminferous tubules, under control of FSH
Male hypogonadism
Def:
primary vs secondary:
Def: failure of tests to produce testosterone or sperm or both
Primary: problem with testes
- low serum testosterone
- HIGH FSH/LH
Secondary: problem with pituitary/hypothalamus
- low serum testosterone
- LOW (or normal) FSH/LH
Causes of primary hypogonadism
1) congenital abnormalites (Eg. klinefelter syndrome, chromosomal abnormalities, mutation in FSH receptor, cryptochidism, varicocele, d/o androgen synthesis, myotonic dystrophy)
2) acquired disease (infection–esp. mumps, radiation, akylating agents, suramin, ketoconazole, glucocorticoids, toxins, trauma, testicular torsion, autoimmune damage, cirrhosis, renal failure, AIDS, idoipathic)
Causes of secondary hypogonadism…
hypopituiarism due do…
- pituitary tumors
- trauma or XRT
- infiltrative diseases (sarcoidosis)
- infection
- kallman syndrome
- Idiopathic
Testosterone deficiency in utero in first trimester…
- incomplete male sexual differentiation–>pseudohermaphroditism
- complete lack testosterone=female external genitalia
- incomplete deficiency= partial virilization with amibuous genitalia
male with micropenis/crytorchidism at birth
testosterone deficiency in utero AFTER first trimester
(normal male sexual differentiation)
10yo boy presents with delayed puberty.
PE:
- small testes (<2.5cm, normal 4-7cm)
- short phallus
- high voice
- decreased muscle mass
- decreased body hair
- delayed bone age
- eunuchoidal skeletal proportions
Dx?
Tests?
Tx/follow-up?
Dx: Testosterone deficiency BEFORE puberty resulting in delayed and incomplete puberty.
Tests:
- low serum testosterone
- serum FSH/LH (high in primary, low in secondary hypo)
- serum prolactin (if secondary)
- pituitary MRI (if secondary)
Tx/follow-up:
- transdermal or IM testosterone replacement
- Check CBC
Sx: teenage male with delayed puberty
PE:
- arm span is more than 5cm greater than height
- heel to pubis is 5cm greater than pubis to crown length
Tests?
Dx?
Tx/follow-up?
-Enuchoidism: Lack of testosterone during puberty causes a delay in epiphyseal closure so that continued presence of growth hormone results in increased length of the long bones
Tests:
- sperm analysis: low sperm count
- low testosterone
- serum FSH/LH (high in primary, low in secondary)
- serum prolactin (if secondary hypo)
- pituitary MRI (if secondary hypo)
Tx/Follow-up:
- transdermal or IM testosterone replacement (unless want fertility then use gonadotropins)
- annual CBC (erythrocytosis)
25 yo male presents with decreased libido and infertility. He also reports having to shave less and feeling easily fatigued.
Dx?
Sx?
Tests?
Tx/follow-up?
Dx: hypogonadism, testosterone deficiency beginning AFTER puberty
Sx:
- decreased libido, soft testes, infertility,
- fatigue, decreased strength and muscle mass
- decreased rate of hair growth (facial, pubic axillary)
- gynecomastia
- osteoporosis if chronic hypogonadism
Tests:
- sperm analysis: low sperm count
- low testosterone
- serum FSH/LH (high in primary, low in secondary)
- serum prolactin (if secondary hypo)
- pituitary MRI (if secondary hypo)
Tx/Follow-up:
- transdermal or IM testosterone replacement (unless want fertility then use gonadotropins)
- annual CBC (erythrocytosis) and PSA (exacerbation of BPH in men >50)
Work-up of hypogonadism in males
-Semen analysis: Low sperm count
-Low serum testosterone (8am—at highest level)
-Serum FSH / LH: (High in primary hypogonadism,
Low or “normal” in secondary hypogonadism)
-Serum prolactin: all patients with secondary hypogonadism
-Pituitary MRI in secondary hypogonadism
KLINEFELTER SYNDROME
- Most common congenital abnormality causing primary hypogonadism
- 1:1000 live male births
- Genotype is 47XXY; may be mosaics (46XY/47XXY)
- Classically: small (<3cm) firm testes, infertility, eunuchoidism and gynecomastia
- Low testosterone with high FSH/LH
- Anti-social personality disorder can be associated
30yo male presents with infertility and gynecomastia.
Hx: antisocial personality d/o
PE: small (<3cm) firm testes, tall–arm span 5cm greater than height
Dx?
Tests?
Tx?
Dx: Klinefelter syndrome (primary hypogonadism)
Tests:
- chromosomal analysis 47XXY (possibly mosaic)
- low testosterone and high FSH
Tx: testosterone replacement
kallman syndrome
- Congenital secondary hypogonadism, caused by deficient secretion of GnRH (Gonadotropin Releasing Hormone)
- Most cases are sporadic but can be inherited as X-linked (usually), or autosomal (dominant or recessive); affects males and females (4:1)
- Associated with anosmia (lack of smell), color blindness, cleft palate, urogenital tract abnormalities and neurosensory hearing loss
- Low testosterone/estradiol & low-normal FSH/LH
13yo male presents with delayed puberty. Also has hearing loss and loss of smell.
hx: cleft palate repair
Tests?
Dx?
Tx?
Dx: kallman syndrome (deficient secretion GnRH–secondary hypogonadism)
Tests:
- low testosterone and high FSH/LH
- serum prolactin
- pituitary MRI
Tx: testosterone replacement
TREATMENT OF HYPOGONADISM
-Testosterone replacement:
- Transdermal (mostly gel, occasionally patches)
- IM injections of testosterone enanthate or cypionate (every 2 weeks)
- Scrotal patches: not used anymore
- Oral forms are not effective and potentially dangerous (hepatic dysfunction)
-All men on testosterone should have regular testing: CBC (erythrocytosis) and PSA (exacerbation of benign prostatic hyperplasia and prostate cancer in men over 50 years)
