lecture 33: diseases and disorders 5: male infertility Flashcards
1
Q
What is the incidence of male infertility?
A
- 40-50% of infertile couples have some degree of male factor problems contributing to their reproductive issues
- world distribution
- increasing?
2
Q
What is history based diagnosis?
A
- family:
- your age!!, relatives (male or female)
- medical:
- childhood disease (mumps, cryptorchidism)
- acute infections
- fevers
- cancer
- diabetes
- neurological disorders
- current medications
- surgical
- bladder, prostate, groin, pelvis, hernia, genitalia, cancer
- social
- occupation, toxicant and radiation exposure, drug use (tobacco, alcohol, caffeine, cocaine, marijuana, androgenic steroids), hot baths or sauna usage
- reproductive
- duration of infertility, earlier pregnancies
- sexual
- STDs, timing and frequency, lubricants
3
Q
What are physical aspects of diagnosis?
A
- phenotypic measures (e.g. BMI, blood pressure)
- sexual development
- hair distribution, gynaecomastia
- penis, urethra
- testis - size, consistency, masses
- epididymis - fullness, discomfort
- spermatic cord - vas deferens, varococeles
- rectal - midline cysts (if suspect obstruction)
- peripheral syndromes, diseases and other abnormalities
4
Q
How can male infertility be diagnosed in a lab test?
A
- semen analysis
- 48-72 hours of sexual abstinence
- WHO criteria - volume and sperm characteristics
- repeat if abnormal in 30 days
- seminal fluid
- fructose: derived from the seminal vesicle (3mg/ml normal)
- post-ejaculatory urine analysis
- semen present
- hormone assessment
- testosterone, oestradiol, FSH
- prolactin, LH
- repeat if abnormal
5
Q
What are the WHO criteria for normal human sperm?
A
- volume: 1.5-5.5mL
- sperm concentration: more than 20 mill/mL
- motility: more than 50% forward progression
- morphology: more than 15% of normal forms
- viscosity: less than 2 on a 1-3 scale
- pH: 7.2 to 7.8
- immune cells: less than 1 million/mL
- aggultination: none
- volume, concentration comparisons:
- ram 0.2-2mL, 3.0 Bill/mL
- bull 8-10mL, 1.5 bill/mL
- stallion 50-100mL, 0.15 bill/mL
- boar 200-400mL, 0.25 bill/mL
- blue whale 7500mL
6
Q
What are causes of abnormal semen analysis?
A
- morphology
- varicocele
- stress
- infection (mumps)
- motility
- immunologic factors
- infections
- defect in sperm structure
- poor liquefaction
- varicocele
- exposure to environmental contaminants
- no ejaculate
- ductal obstruction
- retrograde ejaculation
- ejaculation failure
- hypogonadism
- low volume
- obstruction of ducts
- impaired seminal vesicles
- partial retrograde ejaculation
- infection
7
Q
What are additional semen tests?
A
- semen immune (leukocyte) analysis
- anti-sperm antibody test (both males and females can produce)
- hypo-osmotic swelling test
- sperm penetration assay
- sperm chromatin structure
- sperm DNA damage (TUNEL, COMET, sperm chromatin dispersal)
8
Q
What are additional diagnostic tests?
A
- chromosomal and genetic analysis
- 30-100x risk of genetic abnormalities in infertile men
- karyotyping
- Y chromosome microdeletions (15% of men)
- cystic fibrosis mutation
- radiologic testing (contrast dyes)
- scrotal ultrasound, transrectal ultrasound
- CT scan or MRI of the pelvis
- testis biopsy and vasography
- fine-needle aspiration ‘mapping’ of the testes
- semen culture-bacteria
9
Q
What are causes of male infertility?
A
- if alien scientists were to study the human male’s reproductive system they would probably conclude that he is destined for rapid extinction. Compared to other mammals, humans produce relatively low numbers of viable sperm - Steve Connor
- causes:
- pre-testicular
- testicular
- post-testicular
10
Q
What are pre-testicular causes of male infertility?
A
- hypothalamic disease
- gonadotrophin deficiency (Kallmann syndrome)
- LH deficiency
- FSH deficiency
- congenital hypogonadotrophic syndromes
- pituitary disease
- pituitary insufficiency (tumours, operations, radiation)
- hyperprolactinaemia
- growth hormone deficiency
- exogenous hormones
- oestrogen, androgen, glucocorticoid, thyroid hormones
- medications, supplements
- environmental chemicals
11
Q
What is hypogonadotrophic hypogonadism?
A
- definition
- diminished functional activity and response of the HPG axis due to incomplete development at puberty
- symptoms
- absent virilisation, hypotrophic testes, azoospermia
- low FSH, LH and testosterone
- low libido
- causes
- congenital - Kallman, Klinefelter, and Prader-Willi syndrome
- acquired-pituitary tumour, steroid abuse, testosterone replacement therapy
- mumps
- DES exposure in utero
- treatment
- daily hCG to increase spermatogenesis and androgens
- clomiphene
- HRT with androgens
12
Q
What is hyperprolactinaemia?
A
- definition:
- excessive production of prolactin (milk production and ovulation)
- in men, increased prolactin levels can lead to sexual dysfunction
- symptoms:
- associated with impotence, visual disturbances, sudden weight loss or gain, fatigue or depression
- causes:
- tumours on the pituitary gland (called prolactinomas)
- thyroid gland disorder)
- surgical scars on the chest wall and other chest wall irritations (such as shingles)
- medications including some tranquilizers, high blood pressure medications, and anti-nausea drugs
- oral contraceptives and recreational drugs (e.g. marijuana)
- treatment
- drug - bromocriptine is used to reduce excessive prolactin levels
- surgery is used to remove tumours ( a more risky procedure)
13
Q
What are testicular causes of male infertility?
A
- chromosomal
- klinefelter syndrome (XXY)
- Y chromosome microdeletions
- sertoli-cell-only syndrome (germ cell aplasia)
- gonadotoxins
- radiation and drugs
- systemic disease
- renal or liver failure
- sickle cell anaemia
- defective androgen activity
- malnourishment
- cancer (prostate, testes)
- testis injury
- orchitis, torsion, trauma
- cryptorchidism
- varicocele
- idiopathic (40% of all infertility)
14
Q
What is cryptorchidism?
A
- definition:
- absence of one or both testes to descend in to the scrotum
- most common birth defect of male genetalia esp. premature boys (30%)
- symptoms:
- visually apparent with reduced reproductive function
- impaired fertility
- permanent damage if not corrected quickly
- causes
- unknown
- genetic some evidence (dogs and other species)
- endocrine chemicals?
- maternal diet and alcohol intake. Obesity all risk factors
- treatment
- self-resolving mostly
- surgery to aid testes descent, usually in childhood
- chance surgery can lead to impaired fertility in later life
15
Q
What is varicocele?
A
- definition:
- enlargement of the pampiniform venous plexus within the scrotum
- likely due to defective valves inside the testicle
- occur in 15-20% of men before 30 years old
- symptoms
- usually in left testicle
- visual or palpable reduced size of testicle
- aching pain in scrotum
- altered blood flow
- low testosterone
- increased testis temperature
- impaired sperm production
- causes
- unknown
- left testicular vein connects to renal vein, potential issue
- treatment
- microsurgery - ligation
- embolisation - reduces pressure from abdomen on testis
- limited evidence surgery improves fertility, mainly to stop atrophy
