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REPRODUCTION & GYNAECOLOGY > Male Infertility > Flashcards

Male Infertility Flashcards

1
Q

What 3 things can define our sex?

A
  • Chromosomes (XX/ XY)
  • Gonads (ovaries/ testes)
  • External Genitalia (Vagina/Penis etc)
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2
Q

What are the two primitive reproductive tracts and how do they differentiate into Male and Female?

A
  • Wolffian (mesonephric) and Mullerian (paramesonephric) ducts
  • Testosterone and AMH cause the development of the male reproductive tract
  • Absence of AMH in females causes the mullerian duct to persist and form the female reproductive tract
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3
Q

What does the hormone Dihydrotestosterone (DHT) stimulate?

A

Formation of external genitalia

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4
Q

When do the external genitalia of the foetus begin to differentiate and when are the 2 different sexes recognisable on a scan?

A
  • differentiate from 9 weeks

- able to recognise sex of foetus on scan from 16 weeks

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5
Q

What abnormalities occur during reproductive development if a patient has Androgen insensitivity syndrome?

A
  • X linked insensitivity to androgens
  • Chromosomal Male 46XY
  • Testis develop (but do not descend)
  • AMH present => female internal tract regresses
  • BUT born with female external genitalia
    => Present at puberty with Primary Amenorrhoea/ absent pubic hair
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6
Q

What is the purpose of the corpus spongiosum layer in the penis?

A

Maintains patency of urethra during erection to allow for ejaculation of sperm to pass through

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7
Q

Where do the testis descend from before birth and why is it important that they do this?

A
  • from posterior abdominal wall

- temperature regulation to facilitate spermatogenesis

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8
Q

What is cryptorchidism?

A
  • Patient has reached adulthood and testes have not descended
  • Reduces sperm count
  • If unilateral then patient is usually fertile
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9
Q

What surgical procedures can be used to treat undescended testes?

A

Orchidopexy
- performed below age 14 years to minimise risk of testicular germ cell cancer

Orchidectomy
- consider if undescended as adult (As risk of cancer increases 6X)

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10
Q

What cells are found INSIDE the seminiferous tubules of the testes and what is their role?

A

Sertoli cells

Spermatogenesis

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11
Q

What cells make up the interstitium between the seminiferous tubules of the testes and what is their role?

A

Leydig cells

Secrete testosterone

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12
Q

What covers the head of the sperm to aid entrance into the egg?

A

Acrosome

- filled with enzymes which help to degrade the outer layers of oocyte

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13
Q

What is contained in the neck of the sperm cell?

A

Lots of mitochondria

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14
Q

What are the various roles of the sertoli cells?

A
  • Forms blood-testes barrier (protects sperm from Ab)
  • Provide nutrients for the developing cells
  • Phagocytosis
  • Secrete seminiferous tubule fluid (to carry cells to epididymis)
  • Secrete androgen binding globulin
  • Secrete inhibin and activin hormones (regulates FSH and spermatogenesis)
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15
Q

Explain how GnRH is released from the hypothalamus in males

A
  • Released in bursts every 2-3 hours (begins age 8-12 years) => NON-CYCLICAL unlike females
  • Stimulates anterior pituitary to produce FSH/LH
  • Under negative feedback from testosterone
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16
Q

What effect does testosterone have on a male before birth?

A
  • masculinises reproductive tract

- promotes descent of testes

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17
Q

What effect does testosterone have on a male during puberty?

A

promotes puberty and male characteristics

=> growth and maturation

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18
Q

What effect does testosterone have on a male during adulthood?

A
  • controls spermatogenesis
  • secondary sexual characteristics (male body shape, deep voice, thickens skin)
  • libido, penile erection?
  • SOMETIMES - Aggressive behaviour
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19
Q

What is the role of the inhibin and activin peptides secreted by the sertoli cells?

A

Activin - stimulates FSH production

Inhibin - inhibits FSH production

20
Q

What is meant by Capacitation of the sperm?

A
  • series of biochemical events before fertilisation
    e. g.
  • Chemoattraction to oocyte to bind to zona pellucida
  • Acrosome reaction
  • Hyperactivated motility
21
Q

Where in the fallopian tube does fertilisation normally occur?

A

Ampulla

22
Q

What structures are known as the accessory tissues of the male reproductive tract?

A
  • Epididymis and Vas Deferens
  • Seminal vesicles
  • Prostate Gland
  • Bulbourethral Glands
23
Q

Why do sperm pause in the epididiymis before continuing through the male reproductive tract?

A

concentrates and matures the sperm

24
Q

Describe the route of the sperm during erection, emission and ejaculation from male to female.

A

Erection : blood fills corpora cavernosa

Emission: contraction of accessory sex glands and vas deferens => semen expelled to urethra

Ejaculation: contraction of smooth muscles of urethra and erectile muscles (shoot = sympathetic control)

25
Q

When can problems with premature or retrograde ejaculation occur?

A

neuropathy
prostate surgery
anticholinergic drugs

26
Q

What percentage of infertility is due to male factor?

A

around 30% => 1/3

27
Q

As sperm count is decreasing, the incidence of what other conditions relating to male infertility are increasing?

A

Hypospadias

Testicular cancer

28
Q

What are the 3 groups of causes of Male Infertility?

A

Idiopathic: most common (>50%)
Obstructive: (CF, vasectomy, infection)
Non-Obstructive (MANY causes)

29
Q

Name some non-obstructive causes of male infertility

A
  • Congenital (undescended testes) Cryoptorchadism
  • Infection: mumps
  • Iatrogenic: chemo
  • Pathological: tumour
  • Genetic: XXY, Y microdeletions
  • Semen abnormality
  • Endocrine problem
30
Q

What endocrine disorders cause male infertility

A

Pituitary tumours:

  • acromegaly
  • cushings
  • hyperprolactin

Hypothalmic:

  • idiopathic
  • tumours
  • Kallman’s

Thyroid Disorders
- hyper/hypothyriodism

Diabetes
- decreased sexual function and testosterone

Congenital Adrenal Hyperplasia
- increased testosterone

Androgen insensitivity

Steroid abuse (decreased LH/ FSH/ testosterone)

31
Q

How should male infertility be assessed?

A
  • See patient in their couple
  • History (including andrology hx)
  • Examination (general and genital)
  • Investigations (semen analysis + others depending on results)
32
Q

What is involved in a genital examination for investigation of male infertility?

A
  • testicular volume
  • presence of vas deferens and epididymis
  • penis (urethral orifice)
  • presence of any varicocele/other scrotal swelling
33
Q

What is a normal testicular volume (pre-pubertal and adult)?

A

pre-pubertal: 1-3mls

adults: 12-25mls

34
Q

What testicular volume would indicate infertility?

A

below 5ml unlikely to be fertile

35
Q

What should be analysed in a semen sample?

A 
Volume
Density - numbers of  sperm
Motility - what  proportion  are  moving
Progression - how  well  they  move 
Morphology
36
Q

What factors can affect a semen analysis sample?

A
  • Completeness of sample (1st part of ejaculate is best for sample)
  • Abstinence e.g. <3 days
  • Kept warm during transport (sperm immobile if too cold)
  • Health of man 3 months before production
37
Q

What further investigations can be done after a semen analysis?

A
  • repeat semen analysis 6 weeks later
  • endocrine profile (LH, FSH, testosterone, PRL, TSH)
  • chromosome analysis (including karyoptype, Y microdeletions) CF screen
  • Testicular biopsy
  • Scrotal US scan
38
Q

What features may be relevant on examination if a patient has obstructive male infertility?

A
  • normal testicular volume
  • normal secondary sexual characteristics
  • vas deferens may be absent
  • endocrine profile will also be normal
39
Q

What features may be relevant on examination if a patient has non-obstructive male infertility?

A
  • low testicular volume
  • reduced secondary sexual characteristics
  • vas deferens present

Endocrine = High LH, FSH +/- low testosterone

40
Q

Give examples of specific types of male infertility that can be treated

A
  • reversal of vasectomy if present (75% success rate if reversed within 3 years)
  • carbegoline tx if hyperprolactinamia
  • psychosexual tx if erectile dysfunction (e.g. Sildenafil)
41
Q

What forms of ACT are commonly used for patients with male infertility?

A
  • Intracytoplasmic sperm injection ICSI (may require surgical sperm aspiration)
  • Donor Insemination (DI)
42
Q

What general advice is given to help with male infertility?

A
  • Frequency sexual intercourse: 2-3 X per week
  • Avoid lubricants toxic to sperm
  • Alcohol: < 4 units per day
  • Stop smoking
  • BMI: < 30
  • Avoid tight fitting underwear
  • Avoid prolonged hot baths/sauna
  • Warn about occupations: overheating/exposure to chemicals
43
Q

When is donor sperm insemination indicated?

A
  • azoospermia or very low count
  • failed ICSI treatment
  • genetic conditions
  • infective conditions
44
Q

Describe the procedure of donor sperm insemination

A
  • Sperm donors (not anonymous) matched for recipient characteristics
  • ALSO screened for genetic conditions and STIs
  • Sperm quarantined
  • Prepared semen sample inserted intrauterine at time of ovulation
45
Q

What is the pregnancy rate after donor insemination?

A

15%

REPRODUCTION & GYNAECOLOGY (58 decks)

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