Male hypogonadism

Question 1

Synthesis of testosterone

Answer 1

Derived from cholesterol
- LH required to convert into pregenolone

Pregnenolone into

• Progesterone
• DHEA

Both progesterone and DHEA can be converted to testosterone

TESTO—> DHT and estradiol (requires LH)

Question 2

Testosterone is secreted from the…

Answer 2

Testes

Ovaries

Adrenal glands

Question 3

Normal testosterone levels in men

Answer 3

7mg/ day

- 5 % from adrenal glands

Question 4

Testosterone transport

Answer 4

Mainly albumin
- >50%

SHBG
- 44%

Around 2 % free

Question 5

Testosterone secretion from testes

Answer 5

Secreted by Leydig cells, adjacent to semniferous tubules.

Question 6

Inhibin B

• Function
• Secretion

Answer 6

Hormone secreted by sertoli cells in seminiferous tubules

Negatively inhibits FSH, LH secretion.

Question 7

Anti-mullerian hormone

• Function
• Secretion

Answer 7

Inhibits development of female genital tract in male embryo.

Regulates sex hormone product

Secreted and synthesised by sertoli cells

Question 8

Control of testosterone secretion

Answer 8

GnRH from hypothalamus secreted in a pulsatile fashion
- Stimulates LH and FSH secretion

LH stimulates testosterone secretion from Leydig cells.

FSH stimulates spermatogenesis and inhibin B secretion

Question 9

Testosterone mechanism of action

Answer 9

Steroid hormone–> Passes through plasma membrane

1. Enters into cell and is converted into dihydrotestosterone [DHT]
   - 5-alpha reductase
   - DHT binds to androgen receptor in nucleus
   OR
2. Directly binds to nuclear androgen receptor

Question 10

Testosterone effects

Answer 10

Spermatogenesis

Male phenotype in embryogenesis

Male pattern sexual maturation in puberty and adulthood.

Increases lean body mass, decreases fat mass.

Sexual behaviour

Linear bone growth, prostate and larynx development.

Question 11

Causes of primary hypogonadism

Answer 11

Klinefelter syndrome

Cryptorchidism

Infection: mumps

Radiation

Trauma

Torsion

Idiopathic

Question 12

Causes of secondary hypogonadism

Answer 12

Congenital deficiencies of GnRH

Hyperprolactinoma

Head trauma

Pituitary disorder

GnRH analog

Opioids

Illness

Anorexia

Question 13

Clinical features of male hypogonadism

• First trimester
• Third trimester
• Prepubertal

Answer 13

First trimester

• Female/ ambiguous genitalia
• Partial virilization

Third trimester
- Micropenis

Prepubertal
- Does not undergo or complete puberty

Question 14

Clinical features of male hypogonadism

Answer 14

Incomplete sexual development
- Eunuchodisim

Decreased sexual desire

Decreased spontaenous erections

Breast discomfort/ gynaecomastia

Decreased body hair

Infertility/ low sperm count

Short height

Low trauma fracture/ bone mineral density

Decreased muscle bulk/ strength

Hot flushes/ sweats

Question 15

Less specific signs/ symptoms of hypogonadism

Answer 15

Decrease in:
Energy, motivation, aggressiveness

Depression, dysthymia

Poor concentration/ memory

Mild anaemia- normocytic

Increased body fat/ BMI

Decreased physical performance

Question 16

Conditions with high prevalence of hypogonadism

Answer 16

HIV with weight loss

Sellar disease

Infertility

Osteoporosis

T2 DM

End stage Kidney disease

Meds that affect T cells

• Glucos
• Ketoconazole
• Opioids

COPD

Question 17

Examination [6]

Answer 17

Body hair

Breast

Testicular and penis size

Muscle bulk and strenght

BMD

Arm spna

Question 18

Investigations [9]

Answer 18

Serum testosterone

LH/ FSH

SHBG

Liver function tests

Semen

Karyotyping

Pituitary function

MRI

DEXA

Question 19

Screening guideline

Answer 19

Initial
- Morning testo [highest]

Confirmatory
- Repeat morning total testo

DO NOT SCREEN WHEN
- Acute or subacute illness

If testo is low
- Exluded illness, drugs, nutritional deficiency

If SHBG suspected to be altered
- Free Testso

Question 20

Factors that lower SHBG

Answer 20

Moderate obesity

Nephrotic syndrome

Hypothyroidism

Drugs

• Glucocorticoids
• Progestins
• Androgenic steroids

Question 21

Factors that raises SHBG

Answer 21

Ageing

Hepatic cirrhosis

Hyperthyroidis

Anticonvulsants

Estrogens

HIV

Question 22

Investigations if testo is low

- Normal/ Low LH, FSH

Answer 22

Suggestive of secondary hypogonadism

Check

• Prolactin
• Iron
• Pituitary hormones
• Possible pituitary MRi

Question 23

Investigations for primary hypogonadism

Answer 23

Testosterone
- Low

LH and FSH high

Karyotype [Klinefelter]

Testicular examination

Question 24

Treatment

Answer 24

Testosterone

• Gel
• Injection
• Buccal/ patch, pellet

Question 25

Contraindications of testosterone

Answer 25

Breast/ prostate cancer

DRE showing lump/ hard prostate

PSA> 3ng/ml

Severe, untreated BPH

Erythrocytosis

Hyper-viscosity

Untreated OSA

Severe heart failure

Question 26

Gynaecomastia

• Description
• Epidemiology

Answer 26

Benign proliferation of glandular male breast tissue

• Unilateral or bilateral
• at least 0.5cm in diameter

Common

• 60% of boys in puberty
• 30-70% men

Question 27

Causes of gynaecomastia

Answer 27

Persistent pubertal gynaecomastia

Drugs

Idiopathtic

Cirrhosis

Malnutrition

Hypogonadism

Testicular tumour

Chronic renal insufficiency

Hyperthyroidism

Question 28

Evaluation of male breaststissue

Answer 28

Onset of enlargement

Associated pain/ tenderness?

Is the increase in size glandular or adipose?

Breast cancer?

Testicular tumour?

Question 29

Gynaecomastia investigations

Answer 29

Testo
LH/FSH

Prolactin

LFT< U+Es

B-hCG

Thyroid

Oestrogen

Mamogram

Question 30

Gynaecomastia treatment

Answer 30

Reassurance

Treat cause

Tamoxifen [breast cancer]

Surgery