Introduction:
The testicles present in a male’s scrotum produce sperm or the male reproductive cells, which flow through a series of ducts and mix with a fluid to form semen. Azoospermia, or the absence of sperm in a male’s ejaculate (semen), is one of the main causes of male infertility. It can be challenging for both partners as it leads to significant psychological and emotional distress and affects their quality of life. It can occur due to various causes, including hormonal imbalances, blockages in the reproductive tracts, and genetic or developmental abnormalities. Azoospermia affects approximately one percent of the male population and nearly ten to 15 percent of all males facing infertility issues. Classifying and diagnosing azoospermia involves a complete history, physical examination, and various investigations. However, with advancements in healthcare technology, potentially successful treatments and fertility options are available for couples having problems with conception.
What Is Non-obstructive Azoospermia?
Azoospermia can be present at birth or sometimes develop later in life. It is categorized depending on the presence or absence of obstruction of the reproductive ducts (vas deferens) into obstructive and non-obstructive azoospermia. In obstructive azoospermia (OA), sperm production is normal, but the reproductive tract is blocked, which prevents the sperm from reaching the fluid to form the semen. In non-obstructive azoospermia (NOA), sperm production is impaired, or men fail to produce enough sperm for it to be detected in the semen. According to research, non-obstructive azoospermia is more common than obstructive azoospermia. NOA is considered a non-medically manageable condition as it is very challenging to restore spermatogenesis in the majority of cases.
What Are the Causes of Non-obstructive Azoospermia?
Non-obstructive azoospermia can occur due to various causes, these include:
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Hormonal Imbalances: Testicles require stimulation of pituitary hormones to produce sperm. If the body does not produce enough pituitary hormones or if there is an imbalance of hormones in the individual, it can affect sperm production, leading to non-obstructive azoospermia.
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Genetic Abnormalities: There are several genetic causes for non-obstructive azoospermia, such as Y-chromosome microdeletions, karyotype abnormalities, and a few more that are yet to be understood clearly. The Y chromosome has many genes that are responsible for sperm production; some men may lack these crucial genes, which is known as Y-chromosome deletion. It mostly occurs in about ten percent of cases with azoospermia and hence requires careful screening. Males normally have 46 chromosomes, and having more or less can lead to serious problems in growth and development. An extra chromosome can cause Klinefelter syndrome (a common genetic disorder), resulting in poor testicular function, low sperm count, and reduced testosterone levels.
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Medications: Certain medications, such as psychotherapeutic agents, anti-cancer drugs, narcotics, testosterone supplements, and other steroids can affect sperm production. Treatments such as chemotherapy and radiation may also cause azoospermia. Sperm banking is usually recommended in patients before undergoing chemotherapy or radiation treatment.
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Exposure to Toxins or Radiation: Exposure to toxic chemicals, heavy metals, pesticides, etc can impair sperm production.
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Varicocele: A varicocele is an enlarged or widened vein in the scrotum. It can cause blood to pool in the scrotum, which can negatively impact sperm production. The doctor can identify a varicocele during a physical examination of the scrotum in both supine and standing positions.
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Testicular Damage: Infection of the testicles, trauma, or injury can lead to damage and prevent normal sperm production.
How Is Non-obstructive Azoospermia Diagnosed?
Azoospermia is determined when no sperm is present in the ejaculate. However, at least two semen samples collected at different times must be examined for accurate assessment. It is also confirmed by centrifugation of the semen specimen. After azoospermia is confirmed, the healthcare professional must consider whether it is obstructive or non-obstructive azoospermia. It is determined by taking a detailed patient history, conducting physical examination, evaluating hormones, genetic testing, and ruling out the use of medications causing azoospermia.
Ultrasonography can be recommended to measure the volume of the testes and examine testicular pathophysiology. Computed tomography (CT scan) and magnetic resonance imaging (MRI) can also image the genital tract. After NOA is diagnosed, additional investigations, such as genetic analysis and karyotyping, are recommended. It is observed that approximately 13.7 of patients with azoospermia have an abnormal karyotype of Klinefelter syndrome. Genetic defects or gene mutations can be identified during genetic examinations. The azoospermia factor (AZF) is located on the long arm of the Y chromosome and has three sub-regions. The AZF is the most popular and significant test for diagnosing and managing non-obstructive azoospermia.
How Can Non-obstructive Azoospermia Be Managed?
Treatment of non-obstructive azoospermia is challenging as it is difficult to restore spermatogenesis in most patients apart from those with secondary testicular failure. However, due to advanced treatments these days, some men with NOA may experience the return of sperm to their semen. Adopting certain lifestyle changes, swapping medications, or avoiding toxins or chemical exposure can benefit some patients, whereas others may require direct intervention. However, seeing any definite changes requires at least two to three months. Therefore, discussing the specific condition with the healthcare specialist and seeking medical help as early as possible is important. Some of the treatment options for nonobstructive azoospermia include:
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Retrieval of the Testicular Sperm: It is the only method to achieve pregnancy for affected couples without involving a sperm donor. Spermatozoa are retrieved directly from the testes while causing minimal trauma. Fine-needle aspiration (FNA) and testicular sperm extraction (TESE) are some of the techniques developed for sperm retrieval. TESE is performed with multiple biopsies to enhance the sperm retrieval rate (SRR). However, it involves the removal of large amounts of tissue, which may lead to testicular atrophy following the surgical procedure. FNA was used initially for diagnostic purposes and is a less invasive technique for sperm retrieval compared to TESE. However, studies have shown that SRR is significantly lower with FNA than TESE. Micro-TESE has been widely suggested as it has several advantages and yields a higher rate of spermatozoa per biopsy. It also involves the removal of less testicular tissue and minimizes vascular injury. When Micro-TESE was employed, the SRR was reported to be around 43 to 63 percent.
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Varicocelectomy: Varicocele is a treatable cause of male infertility, and varicocelectomy can help restore fertility in some patients with NOA. It is a procedure during which an operating microscope is used to identify and tie off enlarged and widened veins while preserving the surrounding structures such as arteries, lymph vessels, and vas deferens. Approximately 40 percent of sperm may return to their semen by this technique.
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Hormonal Treatment: Depending on their existing hormone levels, some individuals may benefit from hormonal treatment by coaxing sperm back into their semen or may increase the chance of finding sperm during the retrieval technique. Follicle-stimulating hormone, human chorionic gonadotropin, and Clomiphene are some hormones included in the treatment. It can be employed in cases of secondary testicular dysfunction or low testosterone production.
Conclusion:
The prevalence of infertility has increased globally over the recent years, and azoospermia is one of the primary causes. In non-obstructive azoospermia, the genital ducts may be normal, but the testicles do not produce sperm for various reasons. It affects about ten percent of infertile men and can cause considerable emotional distress for the couple. In most cases, therapy for NOA can be challenging and relies upon assisted reproductive techniques. Understanding the causes and strategizing treatments, procedures, and medications can benefit a few individuals. New diagnostic and therapeutic options such as proteomics, genomics, and artificial intelligence are available, along with conventional surgery and hormonal treatments. However, evidence-based practices, a collaborative approach of healthcare professionals, and continuous emotional support are essential to optimize outcomes in the management of non-obstructive azoospermia.
