Male Hypogonadism

Question 1

how is the majority of testosterone transported and how much is ‘free’

Answer 1

majority is bound to SHBG and albumin, only 0.5-2% is free

Question 2

what is testosterone converted to

Answer 2

dihydrotestosterone and oestradiol

Question 3

what is testosterone converted to dihydrotestosterone and oestradiol by

Answer 3

dihydrotestosterone by 5alpha reductase

oestradiol by aromatase

Question 4

what is the definition of hypogonaadism

Answer 4

clinical syndrome comprising of signs, symptoms and biochemical evidence of testosterone deficiency

Question 5

how does hypogonadism relate to age

Answer 5

incidence increases with age

2-5% in men 40-79y/o

Question 6

what is the difference between primary and secondary hypogonadism

Answer 6

primary = caused by testes pathology
secondary = caused by something external to testes(eg hypothalamus or pituitary

Question 7

what affect does decreased testosterone in primary hypogonadism have on the anterior pituitary and what does this lead to

Answer 7

decreases -ve feedback, so increases LH and FSH release, resulting in hypergonadotrophic hypogonadism

Question 8

how are spermatogenesis and testosterone production affected in primary hypogonadism

Answer 8

both decreased, but spermatogenesis affected more

Question 9

how are FSH, LH and testosterone affected in secondary hypogonadism and what does this lead to

Answer 9

FSH and LH low due to hypothalamic/pituitary dysfunction, testosterone low as result, leads to hypogonadotrophic hypogonadism

Question 10

how are spermatogenesis and testosterone affected in secondary hypogonadism

Answer 10

both decreased and affected equally

Question 11

what are some congenital causes of primary hypogonadism

Answer 11

Klinefelter’s syndrome, cryptorchidism, Y-chromosome microdeletion

Question 12

what are some acquired causes of primary hypogonadism

Answer 12

testicular trauma/torsion, chemo/radiation, varicocele, orchitis, infiltrative disease, medications

Question 13

what is the most common congenital/genetic cause of hypogonadism and how is it diagnosed

Answer 13

Klinefelter’s syndrome, diagnosed by karyotyping

Question 14

what is the inheritance pattern seen in Klinefelter’s syndrome

Answer 14

not inherited, caused by nondisjunction

Question 15

how is fertility and the testes affected in men with Klinefelter’s syndrome

Answer 15

typically infertile and testes are small and firm

Question 16

what is there increased risk of in Klinefelter’s syndrome

Answer 16

increased incidence learning disability, crytporchidism, psychosocial issues
increased risk breast cancer and non-Hodgkin lymphoma

Question 17

what are some of the congenital causes of secondary hypogonadism

Answer 17

Kallmann’s syndrome Prader-Willi syndrome

Question 18

what are some of the acquired causes of secondary hypogonadism

Answer 18

pituitary damage, hyperprolactinaemia, obesity, DM, medications, acute systemic illness, eating disorders

Question 19

describe what Kallmann’s syndrome is

Answer 19

genetic syndrome characterised by isolated GnRH deficiency and hyposmia or anosmia

Question 20

what are the symptoms and signs associated with pre-pubertal onset of hypogonadism

Answer 20

small sexual organs, decreased body hair, high-pitched voice, low libido, gynaecomastia, ‘eunochoidal’ habitus, decreased bone/muscle mass

Question 21

what are the symptoms and signs associated with post-pubertal onset of hypogonadism

Answer 21

normal skeletal and sexual organ size, decreased libido and erections, decreased hair growth, decreased testicular volume, gynaecomastia, decreased muscle/bone mass, decreased energy/motivation