Male Hypogonadism

Question 1

What is male hypogonadism?

Answer 1

Syndrome of decreased testosterone production, sperm production or both

Question 2

Give 3 causes of primary male Hypogonadism

Answer 2

Gonadal dysgenesis (e.g. Klinefelter's syndrome, undescended testicles) 
Gonadal damage (e.g. infection, torsion, trauma, AI, iatrogenic)  
Rare causes (e.g. defects in enzymes involved in testosterone synthesis)

Question 3

Give 5 causes of secondary male Hypogonadism

Answer 3

Pituitary/ Hypothalamic lesions  
GnRH deficiency (Kallmann's syndrome)  
Hyperprolactinaemia  
Systemic/ chronic diseases  
Rare genetic mutations: Prader-Willi +
Laurence-Moon-Biedl syndrome

Question 4

Describe the epidemiology of male Hypogonadism

Answer 4

Primary hypogonadism accounts for 30-40% of male infertility
Most common cause: Klinefelter’s Syndrome (XXY)
Secondary hypogonadism accounts for 1-2%

Question 5

List 5 symptoms of male Hypogonadism

Answer 5

Delayed puberty  
Decreased libido  
Erectile dysfunction 
Infertility  
Symptoms of underlying cause (e.g. Klinefelters --> intellectual dysfunction low IQ, behavioural abnormalities)

Question 6

What may be used to measure testicular volume?

Answer 6

Prader’s orchidometer (normal adult vol = 15-25 mL)

Question 7

List 4 signs of pre pubertal male hypogonadism

Answer 7

Signs of delayed puberty
Gynaecomastia
Eunuchoid proportions (arm span > height)
Features of underlying cause (e.g. undescended testicle, anosmia in Kallmann’s)

Question 8

List 5 signs of post pubertal male hypogonadism

Answer 8

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

Question 9

What can be measured in the blood in suspected male Hypogonadism?

Answer 9

Serum total testosterone
Sex hormone binding globulin (SHBG): check this is not the reason for low free testosterone
Albumin
LH + FSH

Question 10

What are the levels of testosterone, LH and FSH in primary Male Hypogonadism?

Answer 10

Low testosterone

High LH + FSH

Question 11

What are the levels of testosterone, LH and FSH in secondary Male Hypogonadism?

Answer 11

Low testosterone

Inappropriately normal/ low LH + FSH

Question 12

What investigation can be used in primary male Hypogonadism?

Answer 12

Karyotyping (check for Klinefelter’s syndrome)

Question 13

What investigations can be used in secondary male Hypogonadism?

Answer 13

Pituitary function tests  
MRI of the hypothalamic/pituitary area  
Visual field testing  
Smell testing (for anosmia)  
Iron testing (for hereditary haemochromatosis)  
Assess bone age (risk of fracture)

Question 14

List 4 signs of delayed puberty in males

Answer 14

High pitched voice
Decreased pubic/ axillary/ facial hair
Small or undescended testicles
Small penis

Question 15

List 5 signs of Prader-Willi syndrome

Answer 15

Short
Small hands
Almond-shaped eyes
Learning difficulty
Postnatal hypotonia

Question 16

List 4 signs of Laurence-Moon-Biedl syndrome

Answer 16

Obesity
Polydactyly
Retinitis pigmentosa
Learning difficulty