Male Hypogonadism Flashcards
How is testosterone made?
Leydig cells
What kind of hormone is testosterone?
Sterois
How does Testosterone circulate in the blood?
Bound to SHBG or albumin
What enzyme reaction activates testesterone?
Testosterone -> dihydrotestosterone by 5-alpha reductase.
Where is testosterone activated?
In target tissues once it is free.
What is the role of testosterone?
- Growth: sex organs, muscle, epiphyseal plates, larynx, secondary sex characteristics.
- Other: Erythropoiesis, behaviour
- Adults: Muscle mass, mood, bone mass, libido, body shape.
- Fertility: Libido, erection and spermatogenesis.
What is the role of sertoli cells?
Maintain blood-testes barrier.
Remove damaged spermatocytes
Secrete androgen binding protein which locks testosterone in the tested.
What are the child symptoms of hypogonadism?
- Slow growth in teens
- No pubertal growth spurt
- Lack of secondary sexual development
- Small testes and phallus
What are the adult symptoms of hypogondadism?
- Small testes and short phallus low mood - poor libido - erectile dysfunction - low muscle bulk/power - poor energy - sparse body/facial hair - gynacomastia - lots of hair on head.
What size of testes would be seen on an orchidometer in early puberty?
Mid puberty?
Late puberty?
Adult?
Early: 4-6
Mid: 8-10
Late: 12-15
Adult: 20-25
How do you test for hypogonadism?
- Early morning testosterone (should be surge in the morning)
- Free testosterone (normally >200)
- Total testosterone (normally >16)
- SHBG
- LH/FSH (is it pituitary cause?
How would you test fertility in males?
- Semen analysis: 1-3 days after last ejaculation, should be 2-5ml volume.
- Check count, motility and morphology.
In hypogonadotrophic hypogonadism where is the problem?
Hypothalamus or pituitary.
In primary gonadal failure, where is the problem?
Testicles.
Give examples of causes of hypogonadotrophic hypogonadism?
- pituitary surgery
- radiotherapy
- pituitary tumour
- prolactinoma (high prolactin supresses LH and FSH)
- ead injury
- Kallmans syndrome,
What causes Kallmans syndrome?
Failure of cell migration of GnRH cells to the hypohlamus from the olfactory placode.
How is Kallmans syndrome inerited?
Most commonly X-linked. Absence of KAL1 gene. Autosomal dominant (KAL2) Autosomal recessive (KAL3)
What are the symptoms of kallmans syndrome?
Same as hypogonadotropic hypogonadism with added symptom of anosmia or hyponosmia.
- small penis and testes, lack of 2ndry sex characteristics, poor libido, erectile dysfunction, low muscle bulk, gynacomastia etc.
- may have cryptorchidism, deafness, renal agenesis and cleft lip/palate.
Describe testosterone, FSH, LH and prolactin in primary gonadal failure?
low testosterone
normal FSH, LH and prolactin.
List causes of primary gonadal failure?
- Trauma
- Chemotherapy
- Radiotherapy
- Multisystem disorders
- Kleinfelters
- Myotonic dystrophy
What is the gnetic abnormality in Kleinfelters?
XXY
When does gonadal failure manifest in Kleinfelters?
At puberty
How is primary gondalal failure managed?
- Androgen replacement: HypoG treatment: oral, IM or topical. BUT this wont concentrate enough in the testes to regain fertility.
- Physcological support and fertility councilling.
List problems with androgen replacement therapy?
- Mood issues (aggression or behaviour change)
- Libido increased
- Increased haematocrit (increased risk of stroke and heart disease)
- Prostate enlargement (increased chance of BPH or cancer)
- Gynacomastia due to increased aromatase increasing oestrogen.
