Male Infertility Flashcards
What 3 things can define our sex?
- Chromosomes (XX/ XY)
- Gonads (ovaries/ testes)
- External Genitalia (Vagina/Penis etc)
What are the two primitive reproductive tracts and how do they differentiate into Male and Female?
- 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
What does the hormone Dihydrotestosterone (DHT) stimulate?
Formation of external genitalia
When do the external genitalia of the foetus begin to differentiate and when are the 2 different sexes recognisable on a scan?
- differentiate from 9 weeks
- able to recognise sex of foetus on scan from 16 weeks
What abnormalities occur during reproductive development if a patient has Androgen insensitivity syndrome?
- 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
What is the purpose of the corpus spongiosum layer in the penis?
Maintains patency of urethra during erection to allow for ejaculation of sperm to pass through
Where do the testis descend from before birth and why is it important that they do this?
- from posterior abdominal wall
- temperature regulation to facilitate spermatogenesis
What is cryptorchidism?
- Patient has reached adulthood and testes have not descended
- Reduces sperm count
- If unilateral then patient is usually fertile
What surgical procedures can be used to treat undescended testes?
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)
What cells are found INSIDE the seminiferous tubules of the testes and what is their role?
Sertoli cells
Spermatogenesis
What cells make up the interstitium between the seminiferous tubules of the testes and what is their role?
Leydig cells
Secrete testosterone
What covers the head of the sperm to aid entrance into the egg?
Acrosome
- filled with enzymes which help to degrade the outer layers of oocyte
What is contained in the neck of the sperm cell?
Lots of mitochondria
What are the various roles of the sertoli cells?
- 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)
Explain how GnRH is released from the hypothalamus in males
- 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
What effect does testosterone have on a male before birth?
- masculinises reproductive tract
- promotes descent of testes
What effect does testosterone have on a male during puberty?
promotes puberty and male characteristics
=> growth and maturation
What effect does testosterone have on a male during adulthood?
- controls spermatogenesis
- secondary sexual characteristics (male body shape, deep voice, thickens skin)
- libido, penile erection?
- SOMETIMES - Aggressive behaviour
What is the role of the inhibin and activin peptides secreted by the sertoli cells?
Activin - stimulates FSH production
Inhibin - inhibits FSH production
What is meant by Capacitation of the sperm?
- series of biochemical events before fertilisation
e. g. - Chemoattraction to oocyte to bind to zona pellucida
- Acrosome reaction
- Hyperactivated motility
Where in the fallopian tube does fertilisation normally occur?
Ampulla
What structures are known as the accessory tissues of the male reproductive tract?
- Epididymis and Vas Deferens
- Seminal vesicles
- Prostate Gland
- Bulbourethral Glands
Why do sperm pause in the epididiymis before continuing through the male reproductive tract?
concentrates and matures the sperm
Describe the route of the sperm during erection, emission and ejaculation from male to female.
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)
When can problems with premature or retrograde ejaculation occur?
neuropathy
prostate surgery
anticholinergic drugs
What percentage of infertility is due to male factor?
around 30% => 1/3
As sperm count is decreasing, the incidence of what other conditions relating to male infertility are increasing?
Hypospadias
Testicular cancer
What are the 3 groups of causes of Male Infertility?
Idiopathic: most common (>50%)
Obstructive: (CF, vasectomy, infection)
Non-Obstructive (MANY causes)
Name some non-obstructive causes of male infertility
- Congenital (undescended testes) Cryoptorchadism
- Infection: mumps
- Iatrogenic: chemo
- Pathological: tumour
- Genetic: XXY, Y microdeletions
- Semen abnormality
- Endocrine problem
What endocrine disorders cause male infertility
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)
How should male infertility be assessed?
- See patient in their couple
- History (including andrology hx)
- Examination (general and genital)
- Investigations (semen analysis + others depending on results)
What is involved in a genital examination for investigation of male infertility?
- testicular volume
- presence of vas deferens and epididymis
- penis (urethral orifice)
- presence of any varicocele/other scrotal swelling
What is a normal testicular volume (pre-pubertal and adult)?
pre-pubertal: 1-3mls
adults: 12-25mls
What testicular volume would indicate infertility?
below 5ml unlikely to be fertile
What should be analysed in a semen sample?
Volume Density - numbers of sperm Motility - what proportion are moving Progression - how well they move Morphology
What factors can affect a semen analysis sample?
- 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
What further investigations can be done after a semen analysis?
- 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
What features may be relevant on examination if a patient has obstructive male infertility?
- normal testicular volume
- normal secondary sexual characteristics
- vas deferens may be absent
- endocrine profile will also be normal
What features may be relevant on examination if a patient has non-obstructive male infertility?
- low testicular volume
- reduced secondary sexual characteristics
- vas deferens present
Endocrine = High LH, FSH +/- low testosterone
Give examples of specific types of male infertility that can be treated
- 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)
What forms of ACT are commonly used for patients with male infertility?
- Intracytoplasmic sperm injection ICSI (may require surgical sperm aspiration)
- Donor Insemination (DI)
What general advice is given to help with male infertility?
- 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
When is donor sperm insemination indicated?
- azoospermia or very low count
- failed ICSI treatment
- genetic conditions
- infective conditions
Describe the procedure of donor sperm insemination
- 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
What is the pregnancy rate after donor insemination?
15%
