male hypogonadism Flashcards
what does FSH do in males?
- act on Sertoli cells for spermatogenesis
- Sertoli cells release inhibin for negative feedback (turn off FSH)
what does LH do in males?
- LH works on Leydig cells to secrete testosterone
- Leydig cells produce free testosterone which works for negative feedback
what produces testosterone?
Leydig cells
what is the majority of testosterone bound to?
SHBG
what is testosterone converted into?
dihydrotestosterone and oestradiol
what is male hypogonadism?
a clinical syndrome compromising of signs, symptoms and biochemical evidence of testosterone deficiency
who is male hypogonadism more common in?
men aged 40-79
what is primary hypogonadism?
-hypogonadism caused by the testes being primarily affected
what occurs to testosterone and negative feedback in primary hypogonadism?
- decreased testosterone
- decreased negative feedback
what occurs to FSH levels and LH levels in primary hypogonadism and why?
-decreased testosterone production so decreased negative feedback and so higher amounts of FSH and LH
what is hypergonadotrophic hypogonadism?
primary hypogonadism
its when the testes aren’t working well so there is decreased testosterone but there are increased amounts of LH and FSH
how does primary hypogonadism tend to affect testosterone production and spermatogenesis?
spermatogenesis is more affected than testosterone production
what is secondary hypogonadism?
-the hypothalamus/pituitary is affected but the testes can still function normally
what are the testosterone, FSH and LH levels like in secondary hypogonadism?
LH/FSH levels are low/ inappropriately normal (should be high)
testosterone is low
what is hypogonadotrophic hypogonadism?
secondary hypogonadism
- testosterone low
- FSHLH low or inappropriately normal
how does secondary hypogonadism tend to affect testosterone production and spermatogenesis?
they seem to be equally effected
what are some congenital causes of primary hypogonadism?
Klinefelter’s syndrome
Cryptorchidism
Y-chromosome micro deletions
what are some acquired causes of primary hypogonadism?
- testicular trauma/torsion
- chemotherapy/radiation
- varicocele
- orchitis (mumps infection)
- infiltrative disease (e.g. haemochromatosis)
- medications (glucocorticoids, ketoconazole)
what is the most common genetic cause of hypogonadism?
Klinefelter’s syndrome
what causes Klinefelter’s syndrome?
- genetic
- not inherited caused by nondisjunction
How is Klinefelter’s syndrome diagnosed?
by Karyotyping
how does Klinefelter’s syndrome present in men?
- affected men are typically infertile due to tubular damage and have small, firm testes
- wide hips
- long arms and legs
- female type pubic hair pattern
- breast development
- tendancy to grow fewer chest hairs
- narrow shoulders
- poor beard growth
- absent frontal baldness
- learning difficulties
- psychosocial issues
- cryptochordism
what does Klinefelter’s syndrome increase your chances of developing?
- breast cancer
- non Hodgkin lymphoma
what are some congenital causes secondary hypogonadism?
- Kallmann’s syndrome (isolated hypogonadotrophic hypogonadism)
- Prader Willi syndrome
what are some acquired causes of secondary hypogonadism?
- pituitary disease (tumours, infiltrative disease, infection, apoplexy, head trauma)
- hyperprolactinaemia
- obesity
- diabetes
- medication (steroids, opiates)
- acute systemic illness
- eating disorders, excessive exercise
what is Kallmann’s syndrome?
-genetic disorder characterised by isolated GnRH deficiency and hyposmia or anosmia
what is isolated GnRH deficiency associated with?
- unilateral renal agenesis (missing kidney)
- red green colour blindness
- cleft lip/palate
- bimanual synkenesis
who does Kallmanns syndrome tend to affect?
males but less commonly can affect females
what are some pre pubertal onset signs/symptoms of hypogonadism?
Pre pubertal onset:
- small male sexual organs, penis and prostate
- decreased body hair, low libido, high pitched voice
- gynaecomasyia
- tall, slim, long arms and legs
- decreased bone mass and muscle mass
+/- symptoms due to cause
what are some post pubertal signs/symptoms of hypogonadism?
- normal skeletal proportion, 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
+/- symptoms due to cause
how is hypogonadism diagnosed?
- signs/symptoms of low testosterone
- measure AM testosterone
- if low repeat AM testosterone test
- measure LH/FSH
- if elevated could be primary hypogonadism (hypergonadrotrophic hypogonadism) so do karyotypic and iron studies
- if FSH or LH decreased/inappropriately normal then it could be secondary hypogonadism (hypogonadotrophic hypogonadism) so exclude medications, measure prolactin and pituitary hormones, MRI and iron studies
what type of testosterone is active?
free testosterone
what can increase SHBG (sex hormone binding globulin)?
- ageing
- hyperthyroidism
- hyperoestrogenaemia
- liver disease
- HIV
- use of anticonvulsants
what are some advantages of testogel?
- fast onset
- convenient
- mimics circadian rhythm
what are some disadvantages of testogel?
- skin irritation is possible
- interpersonal transfer
- non compliance long term
what are some advantages of testosterone undecanoate (oral testosterone)?
-conveniant
what are some disadvantages of testosterone undecanoate (oral testosterone)?
- variable testosterone levels
- daily or twice daily commitment
- many people experience nausea
what are advantages of testosterone undecanoate e.g. Nebido (intra-muscular injection)?
- steady testosterone levels
- conveniant
- lower frequency administration improves complicance
what are the disadvantages of testosterone undecanoate e.g. Nebiso (intra muscular injection)?
- difficult to withdraw if side effects experiecnes
- local pain at injection side
- coughing following injection
- contraindicated in blood disorders
what are some advantages of testosterone enanthate/proprionate.cipionate e.g. sustain (intra muscular injection)?
- easy to withdraw if side effects experienced
- can be self administered
what are some disadvantages of testosterone enanthate/proprionate.cipionate e.g. sustain (intra muscular injection)?
- variable testosterone levels
- coughing following injection
- local pain at injection site
- contraindicated if bleeding disorders
what are contraindications for testosterone replacement therapy?
- 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
what is done to monitor testosterone replacement therapy?
3-6 monthly whilst starting treatment, annually thereafter
- general health and testosterone concentration
- DRE and PSA
- Haematocrit
- symptoms of sleep apnoea
