Male hypogonadism Flashcards
Recap the male HPG axis
Define what male hypogonadism is
A clinical syndrome comprising of signs, symptoms and biochemical evidence of testosterone deficiency i.e. there is low/reduced gondal (testicular) function
What are the 2 classifications of male hypogonadism ?
- Primary
- Secondary
Define primary male hypogonadism
- This is where the testis are primarily affected, resulting in decreased testosterone production ==> decreased neg feedback (refer to HPG axis)
- In turn Anterior pituitary secretes higher amounts of LH/FSH to try to combat the low testosterone production
- Spermatogenesis is affected more than testosterone production
It is also known as hypergonadotrophic hypogonadism
Define secondary male hypogonadism
- The Hypothalamus/pituitary is primarily affected resulting in LH/FSH low (or inappropriately normal)
- Whereas the testes are capable of normal function
- This results in LH/FSH low (or inappropriately normal) despite low testosterone
- Spermatogenesis & testosterone production are equally affected
It is also known as hypogonadotrophic hypogonadism
List the causes of primary male hypogonadism
Congenital:
- Klinefelter’s syndrome
- Cryptorchidism
- Y-chromosome microdeletions
Acquired:
- Testicular trauma/torsion
- Chemotherapy/radiation
- Varicocele
- Orchitis (mumps infection)
- Infiltrative diseases (e.g. haemochromatosis)
- Medications (glucocorticoids, ketoconazole)
What is Klinefelter’s syndrome?
- It is the most common genetic cause of primary male hypogonadism
- It is not inherited but is caused by 47, XXY
What are the clinical features of Kleinfelter’s syndrome ?
Classically:
- Infertility; small firm testes; decreased facial and pubic hair; loss of libido; impotence.
- Tall and slender, with long legs, narrow shoulders and wide hips.
- Gynaecomastia or history of gynaecomastia during puberty; decreased libido; history of undescended testes.
- Learning disability; delayed speech development; behavioural problems; psychosocial disturbances.
Other features may include tiredness, reduced muscle power and stamina, and truncal obesity (which may be associated with metabolic syndrome).
Increased risk of breast cancer and non-Hodgkin lymphoma
How is Kleinfelter’s syndrome diagnosed ?
Chromosomal analysis - Karotyping
List the causes of secondary male hypogonadism
Congenital
- Kallmann’s syndrome (“isolated hypogonadotrophic hypogonadism”)
- Prader-Willi syndrome
Acquired:
- Pituitary damage
- Tumours
- Infiltrative disease
- Infection (TB)
- Apoplexy
- Head trauma
- Hyperprolactinaemia
- Obesity, diabetes
- Medications (steroids, opioids)
- Acute systemic illness
- Eating disorders, excessive exercise
What is kallmans syndrome
It is an X-linked recessive trait which is inherited resulting in hypogonadotrophic hypogonadism
What are the clinical features of kallmans syndrome ?
Features
- ‘delayed puberty’
- hypogonadism, cryptorchidism
- anosmia
- sex hormone levels are low
- LH, FSH levels are inappropriately low/normal
- patients are typically of normal or above average height
Cleft lip/palate and visual/hearing defects are also seen in some patients
Note - this condition can affect girls but most commonly boys
In questions what would make kallmans syndrome likely ?
The clue given in many questions is lack of smell (anosmia) in a boy with delayed puberty
What are the general signs of hypogonadism in pre-pubertal males ?
- 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
+/- symptoms due to cause (e.g. anosmia with Kallmann’s syndrome)
What are the general signs/symptoms of post-pubertal hypogonadism ?
- 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
+/- symptoms due to cause (e.g. pituitary lesion causing visual field defect)
How is male hypogonadism diagnosed and the underlying cause specified
How is male hypogonadism treated?
Testosterone replacement therapy - multiple different variations available
