Hypogonadism-male

Question 1

Define:

Answer 1

A syndrome of decreased testosterone and/or sperm production

Question 2

Aetiology/risk factors of primary hypogonadism:

Answer 2

o Gonadal dysgenesis (e.g. Klinefelter’s syndrome, undescended testicles)
o Gonadal damage (e.g. infection, torsion, trauma, autoimmune, iatrogenic)
o Rare causes (e.g. defects in enzymes involved in testosterone synthesis)
o Post orchitis: mumps, HIV, brucellosis, leprosy
o Renal failure, liver cirrhosis or alcohol excess (toxic to Leydig cells)

Question 3

Aetiology/risk factors of secondary hypogonadism:

Answer 3

o Pituitary/Hypothalamic lesions
o GnRH deficiency (Kallmann’s syndrome)
o Hyperprolactinaemia
o Systemic/chronic diseases e.g. COPD, HIV, DM
o Rare causes: genetic mutations
o Prader-Willi syndrome (short, small hands, almond-shaped eyes, learning difficulty, postnatal hypotonia)
o Laurence-Moon-Biedl syndrome (obesity, polydactyly, retinitis pigmentosa, learning difficulty)
o Age

Question 4

Epidemiology:

Answer 4

Primary is the cause 30-40% male infertility

Secondary - 1-2% of cases

Question 5

Symptoms:

Answer 5

Delayed puberty

Decreased libido

Impotence

Infertility

Signs of Klinefelter’s - intellectual dysfunction , behavioural abnormalities, poor muscle bulk, tall stature and small testes.

Question 6

Signs pre-pubertal:

Answer 6

o	Signs of delayed puberty 
•	High pitched voice 
•	Decreased pubic/axillary/facial hair
•	Small or undescended testicles 
•	Small penis 
o	Gynaecomastia 
o	Eunuchoid proportions (arm span > height)
o	Features of underlying cause (e.g. undescended testicle, anosmia in Kallmann's syndrome)

Question 7

Signs post-pubertal:

Answer 7

o	Decreased pubic/axillary/facial hair 
o	Soft and small eyes 
o	Gynaecomastia 
o	Fine perioral wrinkles 
o	Features of underlying cause (e.g. visual defects if pituitary cause)

Question 8

Investigations:

Answer 8

•	Serum total testosterone
•	Sex hormone binding globulin (SHBG)
•	Albumin
•	LH and FSH 
•	Primary Hypogonadism:
o	Low testosterone 
o	High LH and FSH 
•	Secondary Hypogonadism:
o	Low testosterone 
o	Inappropriately normal/low LH and FSH
•	Primary - can be investigated using karyotyping (check for Klinefelter's syndrome)
•	Secondary
o	Pituitary function tests 
o	MRI of the hypothalamic/pituitary area
o	Visual field testing 
o	Smell testing (for anosmia)
o	Iron testing (for hereditary haemochromatosis)
•	Assess bone age (risk of fracture)