male infertility Flashcards
Infertility definition
nability of a couple to conceive after 12 months of continuous unprotected sexual intercourse. Affects around 15% of couples worldwide.
Does not mean that a couple could not conceive naturally later on down the line.
Half of the couples which do not conceive during the first year will do so during the second year.
Male infertility
Diagnosed when after testing both partners, reproductive problems have been found in the male. Implicated in 50% of infertility cases.
What is the first step in a male infertility investigation
Semen analysis
Usually the first diagnostic step in male fertility investigations.
Analysis of seminal fluid and sperm parameters as an indicator of male fertility potential.
Remains the gold standard.
WHO criteria for normal semen parameters.
Can be manual semen analysis or computer assisted semen analysis
what are the WHO reference values for normal semen analysis range
Volume 1.5 – 6.0 ml Appearance/Colour Grey-opalescent appearance Liquefaction <30 minutes Sperm concentration >15million/ml Motility >40% Progressive motility >32% Morphology (normal forms) >4% Vitality (live) >58% pH 7.2 - 8.0 Leucocytes <1 million/ml
Key terms for semen analysis abnormalities
Normozoospermia (Normal) – All sperm parameters within normal range.
Azoospermia – No spermatozoa found in semen sample.
Cryptozoozpermia – Virtually no spermatozoa present – only found after extensive search (centrifugation).
Oligozoospermia – Sperm count/conc. <15million/ml.
Asthenozoospermia – Sperm motility <40% (or progressive <32%).
Teratozoospermia – Normal morphology <4%.
Leucospermia – Leucocytes >1million/ml.
Necrozoospermia – Proportion of dead spermatozoa outside normal range.
State the 5 potential causes of male infertility
Sperm production problems
Sperm transport problems (obstruction)
Erectile and ejaculatory problems
Sperm antibodies
Sperm DNA fragmentation
What are 5 potential causes for problems with sperm production
Sperm production problems
Chromosomal/genetic
Hypogonadotrophic hypogonadism
Cyrptorchisdism (a condition in which one or both of the testes fail to descend from the abdomen into the scrotum) and varicocoele (enlarged veins in scrotum)
Torsion and orchitis
Chemo and radiotherapy
Medicined and anabolic steroids
Sperm transport problems (obstruction)
CABVD ( and other obstructions.
Erectile and ejaculatory problems
Retrograde ejaculation and other conditions.
Sperm antibodies
Sperm DNA fragmentation
Describe 2 examples of diseases that can cause sperm production problems on a chromosomal/genetic level
KALLMANS SYNDROME-
Hypergonadotrphic hypogonadism
Azoospermia/severe oligospermia
Sexual dysfunction
1 in 1000 males.
Most show normal sexual development.
JACOBS SYNDROME-
Increased incidence of chromosomally abnormal spermatozoa.
Sperm ranging from normal to azoospermic.
Parental nondisjunction at meiosis II resulting in an extra Y chromosome produces a 47,XYY karyotype in the affected offspring
XX MALE SYNDROME- Happens due to SRY transolcation
1 in 20,000 – 30,000 males
Testosterone deficiency, impaired spermatogenesis
Azoospermia
Y CHROMOSOME DELETIONS
Deletions of genetic material in regions of the Y chromosome called azoospermia factor (AZF) A, B, or C
5-10% of azoospermia or severe oligospermia cases.
How does hypogonadotrophic hypogonadism affect sperm production
Diseases causing congenital hypogonadotropic hypogonadism Kallmann syndrome HH – KAL1, KAL2, PROK2/PROK2R, FGF8
Normosmic IHH – GnRH1/GnRHR, KISS1/GPR54, TAC3/TAC3R
Prader-Willi syndrome – Chr 15
Isolated FSH or LH deficiency – FSH/LR
Laurence-Moon-Bardet-Biedl Syndrome – multiple BBS genes
Diseases causing acquired hypogonadotropic hypogonadism:
Brain tumours – Pituitary adenomas, hypothalamic gliomas, craniopharyngiomas
Prolatin-secreting pituitary adenoma = prolactinoma
Describe cryptorchidism and varicocele
Unilateral or bilateral
Higher testicular temperatures compromise sperm production/quality.
Azoospermia/severe oligospermia (untreated)
The testicular blood vessels originate in the abdomen and course down through the inguinal canal as part of the spermatic cord on their way to the testis. The inguinal canal is the tube down which the testes pass during their descent into the scrotum during foetal life.
The blood, lymph and nervous supply pass through with it and form part of the spermatic chord. Upward flow of blood in the veins from the testis is ensured by small one-way valves that prevent backflow down into the testis, therefore any defect in the valves, or compression of the vein by a nearby structure, can cause of the veins near the testis dilatation, leading to the formation of a varicocele
Varicocele: Unilateral or bilateral
Higher testicular temperatures compromise sperm production/quality.
10-15% of general population; 30-40% of male infertility cases.
Describe sperm production torsion (orchitis)
Rare condition - Twisting of the testis inside the scrotum. This cuts off blood supply to the testis.
Most common in teenagers and young men.
Torsion is a medical emergency and intervention (orchidopexy) within 6hrs gives best chance of avoiding permanent damage.
Orchitis: Inflammation of one or both testes resulting from an infection (bacterial or viral).
Risk of damage to seminiferous tubules.
1 in 10 males experience drop in sperm counts but rarely large enough to cause infertility.
Mumps orchitis used to be the most common cause of orchitis but now less common due to vaccination.
Effect of radiation on sperm production
Radiotherapy: Uses high energy X-rays to kill cancer cells in a specific area while limiting damage to normal cells.
Testicular cancers: Potential damage to the testis, problems with spermatogenesis.
Brain/rest of the body: Could affect glands that produce reproductive hormones e.g. anterior pituitary
Chemotherapy: Attacks cells in the seminiferous epithelium, temporarily or permanently damaging sperm/germ cells.
Return to normal fertility depends on type and duration of chemo.
Effect of certain medicines on sperm production
Medications:
Salazopyrin®: used to treat inflammatory
bowel disease & rheumatoid arthritis. Causes short-term infertility, but reversible after 2-3 months of stopping treatment.
Testosterone (tablets/injections): used to treat androgen deficiency. Can result in a sustained decline in sperm production via –ve feedback on the hypothalamus and anterior pituitary
Effect of certain anabolic steroids on sperm production
Drug formulations that contain natural androgens like testosterone or synthetic androgens that are similar in chemical structure.
Side effects: testicular shrinkage, sustained decline in sperm production via –ve feedback on the hypothalamus and anterior pituitary
Describe sperm transport problems- specifically CABVD
Congenital absence of the bas deferens
Mutations in the cystic fibrosis transmembrane regulator gene (CFTR).
or
Abnormalities in the differentiation of the mesonephric duct.
Up to 5% of azoospermic men.
Obstruction of the vas deferens, epididymis or ejaculatory duct.
Caused by infections, hernias or scarring from corrective surgeries around the male reproductive tract.
Describe erectile and ejaculatory problems
Erectile dysfunction
Premature ejaculation
Delayed ejaculation
Retrograde ejaculation: Semen makes its way into the bladder.
Prostate gland surgery most common cause.
Other causes: diabetes, multiple sclerosis, alpha blockers.
Physical and psychological causes
Physical – diabetes, spinal cord injuries, multiple sclerosis, prostate/bladder surgery, thyroid (overactive or underactive), anti-depressants, beta-blockers, antipsychotics, muscle relaxants, recreational drugs.
Psychological – depression, stress
