Azoospermia

Azoospermia is the medical condition of a man not having any measurable level of sperm in his semen. It is associated with very low levels of fertility or even sterility,

Azoospermia can be classified into three major types 

1. Pretesticular azoospermia

2. Testicular azoospermia

3. Posttesticular azoospermia

 

1. Pretesticular azoospermia

Pretesticular azospermia is characterized by inadequate stimulation of otherwise normal testicles and genital tract. Typically,follicle-stimulating hormone (FSH) levels are low (hypogonadotropic) commensurate with inadequate stimulation of the testes to produce sperm. Examples include hypopituitarism , hyperprolactinemia, and exogenous FSH suppression by testosterone. Chemotherapy may suppress spermatogenesis  Pretesticular azoospermia is seen in about 2% of azoospermia.

2. Testicular azoospermia

In this situation the testes are abnormal, atrophic, or absent, and sperm production severely disturbed to absent. FSH levels tend to be elevated (hypergonadotropic) as the feedback loop is interrupted( Testicular failure). The condition is seen in 49-93% of men with azoospermia. Testicular failure includes absence of failure production as well as low production and maturation arrest during the process of spermatogenesis.

Causes for testicular failure include congenital issues such as in certain genetic conditions (e.g. Klinefelter syndrome), some cases of cryptorchidism or Sertoli cell-only syndrome as well as acquired conditions by infection (orchitis), surgery (trauma, cancer), radiation, or other causes. Mast cells releasing inflammatory mediators appear to directly suppress sperm motilityin a potentially reversible manner, and may be a common pathophysiological mechanism for many causes leading to inflammation

Generally, men with unexplained hypergonadotropic azoospermia need to undergo a chromosomal evaluation.

3. Posttesticular azoospermia

In posttesticular azoospermia sperm are produced but not ejaculated, a condition that affects 7-51% of azoospermic men.The main cause is a physical obstruction (obstructive azoospermia) of the posttesticular genital tracts. The most common reason is a vasectomy done to induce contraceptive sterility.[5] Other obstructions can be congenital (example agenesis of the vas deferens as seen in certain cases of cystic fibrosis) or acquired, such as ejaculatory duct obstruction for instance by infection.

Ejaculatory disorders include retrograde ejaculation and anejaculation; in these conditions sperm are produced but not expelled.