Obstructive Azoospermia Causes

Complications with the delivery of sperm are generally either due to ejaculatory duct obstruction – a problem with the ductal system that carries the sperm – or problems with ejaculation; in this case, the ducts that carry the sperm may be blocked or missing. Depending on the obstruction, obstructive azoospermia is described as either congenital or acquired:

Congenital-obstructive azoospermia caused by:

  • Congenital-obstructive azoospermia caused by geneticGenetic: The patient may have been born with genes that cause infertility characterized by congenital absence of the vas deferens (CAVD). This condition may be both bilateral (both sides) and congenital (from birth).
  • Idiopathic epididymal obstruction: The obstruction may be at the level of the epididymis – the delicate tubular structure that drains the testes – or even higher up in the more muscular vas deferens. The obstruction of the epididymis may arise due to a mechanical blockage following hydrocele or hernia repairs.

Acquired-obstructive azoospermia caused by:

  • Vasectomy: A vasectomy is a surgical procedure that is performed on males as a technique of birth control. During this procedure, the vas deferens – the tubes responsible for carrying sperm to the seminal vesicles from the testicles are cut, tied or burned. The ejaculated semen will no longer contain sperm.
  • Infections: Infections of the male reproductive system such as the prostate or testicles may impact fertility in males.
  • Scrotal surgery: Surgery on the scrotum, or an inguinal (groin) hernia or on other male sex organs may result in damage to the male reproductive system.
  • Trauma: Previous injury or surgery to the pelvis, spine, lower abdomen (stomach); as well as other iatrogenic injuries to the reproductive tractmay damage the male reproductive system. Trauma may negatively impact the production of sperm or result in an obstruction in the transportation or flow of sperm.
  • Ejaculation Problems: Before a man ejaculates, the sperm will need to first be deposited in the urethra in a process referred to as emission. Emission may be hindered by neurological damage stemming from diabetes, surgery or spinal cord injury. In addition, the bladder must be closed down for the sperm to be pushed out the tip of the penis. Failure to close down will force the sperm into the bladder which will be washed out later when the patient is urinating.

Non-Obstructive Azoospermia Causes

There are 3 major reasons behind the lack of sperm production in non-obstructive azoospermia patients: hormonal problems, testicular failure and varicocele.

  • Hormones: Testicular disorders may result in pituitary suppression, which may lead to abnormal hormonal levels that affect sperm production.
  • Drugs: In order to make sperm, the testicles require the stimulation of the pituitary hormones. In the absence or severe decrease of these hormones, the testes are unable to maximally generate sperm. Men who take androgens, anabolic steroids or glucocorticoidseither orally or by injection for body building tend to shut down the production of hormones necessary for the production of sperm. Other drugs such as antibiotics and those used for the treatment of cancer or inflammation may also affect fertility in males by causing abnormal levels of hormones, which impacts sperm production. Drinking alcohol, smoking and the use of illegal drugs may also result in sperm production problems.
  • Testicular Failure: This refers to the inability of the seminiferous epithelium – the part of the testicle that produces sperm – to produce a sufficient number of mature sperm. This failure may take place at any stage in sperm production for various reasons. For one, the testicle may be completely lacking the cells that undergo divisions to become sperm in a condition referred to as Sertoli cell-only syndrome. Another reason could be the inability of the sperm to complete their development, in a condition termed as “maturation arrest”. The patient should be screened for genetic abnormalities which could be the cause of the latter condition.
  • varicoceleVaricocele effect: A varicocele is a condition characterized by dilated veins (blood vessels) in the scrotum, not very different from having varicose veins in the legs. The veins become dilated (widened) and enlarged due to the failure of the blood to properly drain from them. The dilated veins allow additional blood to pool in the scrotum which negatively impacts the production of sperm.
  • Genetic: The patient may have been born with genes that affect sperm production such as in the case of men suffering from Klinefelter’s syndrome. The genes may similarly affect the formation of the reproductive sex organs, as in the case of Kallmann’s syndrome.
  • Radiation: Radiation such as that used in the treatment of cancer may also affect the production of sperm.
  • Retrograde Ejaculation: This is characterized by a condition in which semen travels into the bladder instead of going outside the body. This is usually due to a problem with the neck of the bladder which may be as a result of diabetes, medicines or spinal cord injuries. In cases of azoospermic males with a low ejaculatory volume of less than 1ml, retrograde ejaculation may be ruled out as the cause of the condition.
  • Other factors: Heat, heavy metals, pesticides and undescended testes (testicles that failed to move from the abdomen into the scrotum) may also impact the production of sperm.

Conditions That Cause Azoospermia

  • Primary testicular failure, Klinefelter’s syndrome
  • Genetic infertility due to abnormal chromosomes (karyotype)
  • Y chromosome microdeletions
  • Unexplained genetic infertility
  • Unexplained gonadotropin deficiency
  • Secondary testicular failure, Kallman’s syndrome
  • Hypothalamic/pituitary tumor
  • Cancer treatment (chemotherapy, radiation, surgery)
  • Hyperprolactinemia
  • Varicocele effect
  • Testosterone supplements
  • Pituitary suppression, drug induced (anabolic steroids, alcohol, glucocorticoids)
  • Congenital adrenal hyperplasia
  • Diabetes mellitus
  • Severe illness (cancer, kidney or liver failure)
  • Sickle cell anemia
  • Sperm autoimmunity
  • Hemachromatosis
  • Pesticide/toxin exposure (including hot tubs and baths)
  • Obstruction, congenital absence of the vas deferens (CAVD)
  • Undescended testicles at birth
  • Ejaculatory duct obstruction
  • Scrotal trauma or surgery
  • Vasectomy
  • Epididymitis
  • Young syndrome