Male hypogonadism Flashcards Preview

203: The endocrine system > Male hypogonadism > Flashcards

Flashcards in Male hypogonadism Deck (30)
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1

Synthesis of testosterone

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)

2

Testosterone is secreted from the...

Testes

Ovaries

Adrenal glands

3

Normal testosterone levels in men

7mg/ day
- 5 % from adrenal glands

4

Testosterone transport

Mainly albumin
- >50%

SHBG
- 44%

Around 2 % free

5

Testosterone secretion from testes

Secreted by Leydig cells, adjacent to semniferous tubules.

6

Inhibin B
- Function
- Secretion

Hormone secreted by sertoli cells in seminiferous tubules

Negatively inhibits FSH, LH secretion.

7

Anti-mullerian hormone
- Function
- Secretion

Inhibits development of female genital tract in male embryo.

Regulates sex hormone product

Secreted and synthesised by sertoli cells

8

Control of testosterone secretion

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

9

Testosterone mechanism of action

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

10

Testosterone effects

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.

11

Causes of primary hypogonadism

Klinefelter syndrome

Cryptorchidism

Infection: mumps

Radiation

Trauma

Torsion

Idiopathic

12

Causes of secondary hypogonadism

Congenital deficiencies of GnRH

Hyperprolactinoma

Head trauma

Pituitary disorder

GnRH analog

Opioids

Illness

Anorexia

13

Clinical features of male hypogonadism
- First trimester
- Third trimester
- Prepubertal

First trimester
- Female/ ambiguous genitalia
- Partial virilization

Third trimester
- Micropenis

Prepubertal
- Does not undergo or complete puberty

14

Clinical features of male hypogonadism

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

15

Less specific signs/ symptoms of hypogonadism

Decrease in:
Energy, motivation, aggressiveness

Depression, dysthymia

Poor concentration/ memory

Mild anaemia- normocytic

Increased body fat/ BMI

Decreased physical performance

16

Conditions with high prevalence of hypogonadism

HIV with weight loss

Sellar disease

Infertility

Osteoporosis

T2 DM

End stage Kidney disease

Meds that affect T cells
- Glucos
- Ketoconazole
- Opioids

COPD

17

Examination [6]

Body hair

Breast

Testicular and penis size

Muscle bulk and strenght

BMD

Arm spna

18

Investigations [9]

Serum testosterone

LH/ FSH

SHBG

Liver function tests

Semen

Karyotyping

Pituitary function

MRI

DEXA

19

Screening guideline

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

20

Factors that lower SHBG

Moderate obesity

Nephrotic syndrome

Hypothyroidism

Drugs
- Glucocorticoids
- Progestins
- Androgenic steroids

21

Factors that raises SHBG

Ageing

Hepatic cirrhosis

Hyperthyroidis

Anticonvulsants

Estrogens

HIV

22

Investigations if testo is low
- Normal/ Low LH, FSH

Suggestive of secondary hypogonadism

Check
- Prolactin
- Iron
- Pituitary hormones
- Possible pituitary MRi

23

Investigations for primary hypogonadism

Testosterone
- Low

LH and FSH high

Karyotype [Klinefelter]

Testicular examination

24

Treatment

Testosterone
- Gel
- Injection
- Buccal/ patch, pellet

25

Contraindications of testosterone

Breast/ prostate cancer

DRE showing lump/ hard prostate

PSA> 3ng/ml

Severe, untreated BPH

Erythrocytosis

Hyper-viscosity

Untreated OSA

Severe heart failure

26

Gynaecomastia
- Description
- Epidemiology

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

27

Causes of gynaecomastia

Persistent pubertal gynaecomastia

Drugs

Idiopathtic

Cirrhosis

Malnutrition

Hypogonadism

Testicular tumour

Chronic renal insufficiency

Hyperthyroidism

28

Evaluation of male breaststissue

Onset of enlargement

Associated pain/ tenderness?

Is the increase in size glandular or adipose?

Breast cancer?

Testicular tumour?

29

Gynaecomastia investigations

Testo
LH/FSH

Prolactin

LFT< U+Es

B-hCG

Thyroid

Oestrogen

Mamogram

30

Gynaecomastia treatment

Reassurance

Treat cause

Tamoxifen [breast cancer]

Surgery