Male Hypogonadism Flashcards
how is the majority of testosterone transported and how much is ‘free’
majority is bound to SHBG and albumin, only 0.5-2% is free
what is testosterone converted to
dihydrotestosterone and oestradiol
what is testosterone converted to dihydrotestosterone and oestradiol by
dihydrotestosterone by 5alpha reductase
oestradiol by aromatase
what is the definition of hypogonaadism
clinical syndrome comprising of signs, symptoms and biochemical evidence of testosterone deficiency
how does hypogonadism relate to age
incidence increases with age
2-5% in men 40-79y/o
what is the difference between primary and secondary hypogonadism
primary = caused by testes pathology secondary = caused by something external to testes(eg hypothalamus or pituitary
what affect does decreased testosterone in primary hypogonadism have on the anterior pituitary and what does this lead to
decreases -ve feedback, so increases LH and FSH release, resulting in hypergonadotrophic hypogonadism
how are spermatogenesis and testosterone production affected in primary hypogonadism
both decreased, but spermatogenesis affected more
how are FSH, LH and testosterone affected in secondary hypogonadism and what does this lead to
FSH and LH low due to hypothalamic/pituitary dysfunction, testosterone low as result, leads to hypogonadotrophic hypogonadism
how are spermatogenesis and testosterone affected in secondary hypogonadism
both decreased and affected equally
what are some congenital causes of primary hypogonadism
Klinefelter’s syndrome, cryptorchidism, Y-chromosome microdeletion
what are some acquired causes of primary hypogonadism
testicular trauma/torsion, chemo/radiation, varicocele, orchitis, infiltrative disease, medications
what is the most common congenital/genetic cause of hypogonadism and how is it diagnosed
Klinefelter’s syndrome, diagnosed by karyotyping
what is the inheritance pattern seen in Klinefelter’s syndrome
not inherited, caused by nondisjunction
how is fertility and the testes affected in men with Klinefelter’s syndrome
typically infertile and testes are small and firm
what is there increased risk of in Klinefelter’s syndrome
increased incidence learning disability, crytporchidism, psychosocial issues
increased risk breast cancer and non-Hodgkin lymphoma
what are some of the congenital causes of secondary hypogonadism
Kallmann’s syndrome Prader-Willi syndrome
what are some of the acquired causes of secondary hypogonadism
pituitary damage, hyperprolactinaemia, obesity, DM, medications, acute systemic illness, eating disorders
describe what Kallmann’s syndrome is
genetic syndrome characterised by isolated GnRH deficiency and hyposmia or anosmia
what are the symptoms and signs associated with pre-pubertal onset of hypogonadism
small sexual organs, decreased body hair, high-pitched voice, low libido, gynaecomastia, ‘eunochoidal’ habitus, decreased bone/muscle mass
what are the symptoms and signs associated with post-pubertal onset of hypogonadism
normal skeletal and sexual organ size, decreased libido and erections, decreased hair growth, decreased testicular volume, gynaecomastia, decreased muscle/bone mass, decreased energy/motivation
