During a fertility assessment of the couple, a spermogram is systematically performed in humans. By evaluating different sperm parameters, this biological examination allows to update different spermatic anomalies, such as azoospermia, a total absence of spermatozoa.
What is azoospermia?
Azoospermia is a sperm abnormality characterized by the total absence of spermatozoa in the ejaculate. It obviously leads to the infertility of man, because in the absence of spermatozoa there can be fertilization.
Azoospermia affects less than 1% of men in the general population, ie 5 to 15% of infertile men .
The causes of Azoospermia
Depending on the cause, there are two types of azoospermia:
Secretory azoospermia (or NOA, for non-obstructive azoospermia)
Spermatogenesis is impaired or nil and the testes do not produce spermatozoa. The cause of this spermatogenic defect can be:
- hormonal, with hypogonadism (absence or abnormality of secretion of sex hormones) that can be congenital (Kallmann-Morsier syndrome for example) or acquired, especially because of pituitary tumors that alter the functioning of the hypothalamic-pituitary axis or after a treatment (chemotherapy for example);
- Genetics: Klinefelter syndrome (presence of an extra X chromosome), affecting 1 in 1200 , chromosome structure abnormality, (microdeletion, ie loss of a fragment, Y chromosome in particular), translocation (one chromosome segment detaches and attaches to another). These chromosomal abnormalities account for 5.8% of male infertility problems ;
- bilateral cryptorchidism: the two testicles did not descend into the bursa, which alters the process of spermatogenesis;
- an infection: prostatitis, orchitis.
Obstructive or excretory azoospermia (OA, obstructive azoospermia)
The testes produce many spermatozoa but they can not be externalized because of a closing of the channels (epididymis, vas deferens or ejaculatory ducts). The cause may be of origin:
- congenital: the seminal pathways have been altered since embryogenesis, leading to absence of vas deferens. In men with cystic fibrosis, a mutation of the CFTR gene can cause a lack of vas deferens;
- Infectious: the pathways were blocked following an infection (epididymitis, prostatectesitis, prostatic utricle).
Symptoms of Azoospermia
The main symptom of azoospermia is infertility.
The diagnosis of azoospermia is made during a consultation of infertility, which includes in humans systematically a spermogram. This examination consists of analyzing the contents of the ejaculate (sperm), evaluating different parameters and comparing the results to the standards established by the WHO.
In the case of azoospermia, no spermatozoa are found after centrifugation of the entire ejaculate. To make the diagnosis, however, it is necessary to perform one or even two other spermograms, 3 months apart each, because spermatogenesis (production cycle of sperm) lasts about 72 days. In the absence of 2 to 3 consecutive sperm production, the diagnosis of azoospermia will be made.
Various complementary examinations will be carried out to refine the diagnosis and attempt to identify the cause of this azoospermia:
- clinical examination with palpation of the testes, measurement of testicular volume, palpation of the epididymis, vas deferens;
- a seminal biochemistry (or biochemical study of sperm), to analyze various secretions (zinc, citrate, fructose, carnitine, acid phosphatases …) contained in the seminal plasma and from different glands of the genital tract (seminal vesicle, prostate, epididymis ). In case of obstruction of the channels, these secretions can be disturbed and biochemical analysis can help locate the level of the obstacle;
- a hormonal assessment by blood test, including an assay of FSH (follicle stimulating hormone). High FSH levels indicate testicular involvement; a low FSH level of high involvement (at the hypothalamic-pituitary axis);
- a blood test serology, to search for an infection, such as chlamydia, that may or may have caused excretory tract damage;
- a scrotal ultrasound to control the testes and detect abnormalities of the vas deferens or epididymis;
- a blood karyotype and genetic analyzes to search for a genetic abnormality;
- a testicular biopsy consisting in collecting, under anesthesia, a fragment of tissue inside the testicle;
- an X-ray or an MRI of the pituitary is sometimes proposed if a high pathology is suspected.
Treatment and prevention
In case of secretory azoospermia of hormonal origin following an alteration of the hypothalamic-pituitary axis (hypogonadotropic hypogonadism), a hormonal treatment may be proposed to restore the hormonal secretions necessary for spermatogenesis.
In other cases, a search for spermatozoa by surgery can be performed either in the testes during the testicular biopsy (TESE technique: TEsticular Sperm Extraction) if it is a secretory azoospermia, or in the epididymis (MESA technique, microsurgical epididymal sperm aspiration) if it is an obstructive azoospermia.
If sperm are taken, they can be used immediately after biopsy (synchronous sampling) or after freezing (asynchronous sampling) during IVF (in vitro fertilization) with ICSI (intracytoplasmic sperm injection). This MPA technique involves injecting a single sperm directly into each mature oocyte. Spermatozoa being selected and “forced” fertilization, ICSI generally achieves better results than conventional IVF.