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
Pretesticular azoospermia 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.
In post testicular 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 post testicular 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 is produced but not expelled.
In this situation, the testes are abnormal, atrophic, or absent, and sperm production severely disturbed to absent. FSH levels tend to be elevated (hyper-gonadotropic) as the feedback loop is interrupted( Testicular failure). The condition is seen in 49-93% of men with azoospermia. Testicular failure includes the 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 motility in a potentially reversible manner and maybe a common pathophysiological mechanism for many causes leading to inflammation
Generally, men with unexplained hyper-gonadotropic azoospermia need to undergo a chromosomal evaluation.
