Hypogonadism (MALE)

Question 1

Define Hypogonadism?

Answer 1

A syndrome of decreased testosterone production, sperm production or both

Question 2

What is the aetiology of Primary Hypogonadism?

Answer 2

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

Question 3

What is the aetiology of Secondary Hypogonadism?

Answer 3

Pituitary/Hypothalamic Lesions
GnRH deficiency (Kallmann's Syndrome)
Hyperprolactinaemia 
Systemic/Chronic Diseases 
Rare causes: genetic mutations 
Prader-Willi Syndrome 
Laurence-Moon-Biedl Syndrome

Question 4

What are some of the symptoms and signs of Prader-Willi syndrome?

Answer 4

Short 
Slow Hands 
Almond-shaped eyes 
Learning difficulty 
Postnatal Hypotonia

Question 5

What are some of the symptoms and signs of Laurence-Moon-Biedl Syndrome?

Answer 5

Obesity
Polydactyly
Retinitis Pigmentosa
Learning difficulty

Question 6

What is the epidemiology of Hypogonadism?

Answer 6

Primary Hypogonadism accounts for 30-40% of male infertility
Secondary Hypogonadism accounts for 1-2%

Question 7

What is the most common cause of Primary Hypogonadism?

Answer 7

Klinefelter’s Syndrome (XXY)

Question 8

What are the presenting symptoms of Hypogonadism?

Answer 8

Delayed Puberty 
Decreased Libido
Impotence 
Infertility 
Symptoms of underlying cause (e.g. Klinefelters leads to intellectual dysfunction, behavioural abnormalities)

Question 9

What do we do for Hypogonadism on physical examination?

Answer 9

Measure testicular volume using Prader’s orchidometer (normal adult volume = 15-25 mL)

Question 10

What are the signs of Prepubertal Hypogonadism on physical examination?

Answer 10

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

Question 11

What are the signs of delayed puberty?

Answer 11

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

Question 12

What are the signs of Postpubertal Hypogonadism?

Answer 12

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

Question 13

What investigations would you do for Hypogonadism?

Answer 13

Serum Total Testosterone 
Sex Hormone Binding Globulin (SHBG)
Albumin 
Lh and FSH 
Assess bone age

Question 14

What would you see for Testosterone in the different type of Hypogonadism?

Answer 14

Primary and Secondary - LOW

Question 15

What would you say for LH and FSH for the different types of Hypogonadism?

Answer 15

Primary - HIGH LH and FSH

Secondary - Inappropriately normal/low LH and FSH

Question 16

How can Primary Hypogonadism be investigated?

Answer 16

Can be investigated using karyotyping (check for Klinefelter’s Syndrome)

Question 17

How can Secondary Hypogonadism be investigated?

Answer 17

Pituitary function tests 
MRI of the hypothalamic/pituitary area 
Visual Field Testing 
Smell testing (for anosmia)
Iron testing (for hereditary haemochromatosis)

Question 18

Why do we assess bone age for Hypogonadism?

Answer 18

Risk of Fracture