Male hypogonadism

Question 1

what is the hypothalamus stimulates by

Answer 1

kisspeptin to release pulses of gonadotropin releasing hormone- GnRH

Question 2

what is the anterior pituitary stimulated by to release

Answer 2

GnRH to release LH and FSH

Question 3

what are the gonads stimulated by

Answer 3

LH/FSH to produce testosterone

Question 4

what provides negative feedback to hypothalamus and pituitary

Answer 4

testosterone

Question 5

what is testosterone produced by

Answer 5

leydig cells under control of LH

Question 6

what is testosterone converted to

Answer 6

dihydrotestosterone - highly active form and oestradiol

Question 7

what is male hypogonadism

Answer 7

low/ reduced gonadal testicular function

Question 8

primary hypogonadism

Answer 8

problem with testes

decreased testosterone - decreased negative feedback

anterior pituitary secretes higher amunts of lH/FSH

spermatogenesis affected more than testosterone production

Question 9

secondary hypogonadism

Answer 9

problem with hypothalamus/ anterior pituitary

spermatogenesis and testosterone production affected equally

LH/FSH low despite low testosterone

Question 10

causes of primary hypogonadism

Answer 10

Klinefelter’s syndrome

Cryptorchidism

Y-chromosome microdeletions

Testicular trauma/torsion

Chemotherapy/radiation

Varicocele

Orchitis (mumps infection)

Infiltrative diseases (e.g. haemochromatosis)

Medications (glucocorticoids, ketoconazole)

Question 11

most common genetic cause of hypogonadism

Answer 11

klinefelters syndrome
non disjunction
usually 47,XXY

affected men are typically infeertile

Question 12

signs in klinefelters syndrom

Answer 12

breast development
female type hair pubic pattern
long arms and legs
wide hips
narrow shoulders
poor beard growth
frontal baldness/ absent
fewer chest hairs

Question 13

causes of secondary hypogonadism

Answer 13

Kallmann’s syndrome (“isolated hypogonadotrophic hypogonadism”)

Prader-Willi syndrome

Pituitary damage
Tumours
Infiltrative disease
Infection (TB)
Apoplexy
Head trauma

Hyperprolactinaemia
Obesity, diabetes
Medications (steroids, opioids)
Acute systemic illness
Eating disorders, excessive exercise

Question 14

kallmans syndrome

Answer 14

geentc disorder characterised by gnrh def and hyposmia or anosmia

Question 15

pre pubertal onset symptoms and signs of hypogonadism

Answer 15

Small male sexual organs e.g. small testes (volume <5 mL), penis and prostate
Decreased body hair, high-pitched voice, low libido
Gynaecomastia
‘Eunuchoidal’ habitus (tall, slim, long arms and legs)
Decreased bone and muscle mass

Question 16

post pubertal symptoms and signs

Answer 16

Normal skeletal proportions, penis/prostate size and voice
Decreased libido, decreased spontaneous erections
Decreased pubic/axillary hair, reduced shaving frequency
Decreased testicular volume
Gynaecomastia
Decreased muscle and bone mass
Decreased energy and motivation

Question 17

diagnosis of hypogonadism

Answer 17

measure AM testosterone

measure LH/FSH

Question 18

if lH/FSH elevated

Answer 18

primary

Question 19

if LH/FSH low/ inappropritely normal

Answer 19

secondary

Question 20

when should testosterone be measured

Answer 20

between 8am -11am

Question 21

what can cause increased concentrations of SHBG

Answer 21

ageing
hyperthyroidism
liver disease
HIV
use of anticonvulsants

Question 22

what can cause decreased concentrations of SHBG

Answer 22

obesity
insulin resistance and diabetes
hypothyroidism
growth hormone excess
glucocorticoids
androgens
progestins
nephortic syndrome

Question 23

management if fertility is important

Answer 23

GnRH or gonadotrophin therapy

Question 24

management if fertility not important

Answer 24

Establish/maintain secondary sexual characteristics
Maintain sexual function
Improve body composition
Improve quality of life

by giving testosterone replacement therapy

Question 25

what is testosterone replacement therapy contraindicated in

Answer 25

Confirmed hormone responsive cancer (e.g. prostate/breast)

• Possible prostate cancer (e.g. raised PSA, suspicious prostate on DRE)
• Haematocrit >50%
• Severe sleep apnoea/heart failure

Question 26

monitoring of testostrone replacement therapy

Answer 26

3-6 monthly whilst starting treatment then annually