Male Infertility

Question 1

Male infertility can be divided into what 3 major categories?

-which is most common?

Answer 1

1. pre testicular
2. testicular–most common
3. post testicular

Question 2

Pre testicular causes of male infertility

-general description

Answer 2

• typically endocrinopathies (eg pituitary tumors)
• highly treatable

Question 3

Testicular causes of male infertility

-general description

Answer 3

• most common cause of male infertility and usually reversible
• eg varicoceles, gonadotoxins

Question 4

Post testicular causes of male infertility

-general description

Answer 4

Problem in delivering semen to ejaculate.

eg obstruction, ejaculation disorders.

Question 5

Evaluation of infertile male:

-what initial tests to do (4)

Answer 5

1. full history/physical exam
2. semen analysis (at least 2 samples)
3. hormone studies (HPG axis–T, FSH, LH, estradiol, prolactin)
4. Ultrasound of scrotum if testicular abnormality identified (beware of testicular cancer in young men)

Question 6

You start treatment today on an infertile male that affects spermatogenesis.

How long to wait before doing a new semen analysis to look at changes?

Answer 6

Wait 90 days:

It takes 70 days for stem cells to become mature sperm. 20 days for sperm to transit epididymis.

Question 7

Infertile male:

1. For hormone testing, what are the first 2 hormones levels to test?
2. What hormones to look at next?

Answer 7

1. FSH and Testosterone.

this is to measure the integrity of the HPG axis.

2. If T is low, repeat in the early morning. Also order LH, prolactin, estradiol

Question 8

Semen analysis

-measures levels of what? (4 things)

Answer 8

1. semen volume
2. sperm concentration
3. sperm motility
4. total motile sperm/ejaculate ratio

Question 9

What are the top 2 causes of male infertility?

Answer 9

1. varicocele (40%)
2. idiopathic (25%)

Question 10

Why does varicocele lead to infertility?

Answer 10

Buildup of blood from vein congestion reduces the countercurrent heat exchange system.

Heat results in low sperm

Question 11

How is cystic fibrosis associated with male infertility?

Answer 11

CRTR gene mutations (cystic fibrosis transmembrane-conductance regulator) cause involution of the genital ducts during embryogenesis.

This is CBAVD (Congenital Bilateral Absence of Vas Deferens)

Question 12

CBAVD

• what is it
• divided into what 2 main types?

Answer 12

Congenital Bilateral Absence of Vas Deferens

-1-2% of male infertility

Divided into:

1. CFTR mutations (80-90%)
2. Renal agenesis

Question 13

CBAVD

-genetic inheritance pattern?

Answer 13

Most cases are associated with CFTR mutations, auto recessive.

Genetic counseling essential for both partners.

Question 14

CBAVD assoc with cystic fibrosis

-mechanism

Answer 14

-80-90% are assoc with mutations in the CFTR (cystic fibrosis transmembrane conductance regulator) gene. Mutations result in involution of the genital ducts during embryogenesis.

Question 15

CBAVD not associated with cystic fibrosis

-mechanism

Answer 15

CBAVD not associated with cystic fibrosis is probably due to Renal agenesis during embryonic development.

(defects in mesonephric duct devo leads to agenesis of genital ducts and ipsilateral kidney.)

Question 16

CBAVD:

-you look for CFTR mutation but it is negative. Do what next?

Answer 16

Do a renal ultrasound to look for Renal agenesis. Defect in mesonephric duct devo causes agenesis of genital ducts and ipsilateral kidney.

80-90% of CBAVD are due to CFTR mutations, but some are due to renal agenesis.

Question 17

Why do at least 2 semen samples for semen analaysis?

Answer 17

Fluctuations in the levels measured by semen analysis are very normal.