Post Date December, 03 2023
1. Congenital bilateral absence of vas deferens is one of the causes of azoospermia in male infertility. During clinical examination of patients, except for the inability to touch the vas deferens on both sides of the scrotum, laboratory examination can reveal that the patient has a low semen volume (less than lml), no sperm, no adhesiveness, no fructose, low pH (around 6.5), acidic, and normal levels of FSH, LH, and testosterone. In recent years, methods such as CT and MRI have been used to directly observe the presence and size of seminal vesicles, vas deferens, and ejaculatory ducts. However, the aforementioned diagnostic indicators are still simple and applicable.
2. The main germs causing genital tract infection include gonococcus, syphilis, trichomonas, tuberculosis and candida albicans. After genital infection, due to the pathological changes of inflammation, all vas deferens are blocked, which becomes azoospermia. Mild and asymptomatic reproductive tract infections, although not completely damaged in the vas deferens, can lead to bacterial contamination in semen, resulting in toxic breakdown of sperm cells, shortened sperm lifespan, and sperm agglutination. Sometimes, it can also cause premature shedding of immature sperm. Other pathogens can also be found in semen, such as mycoplasma, hepatitis virus, and non gonococcal urethral infections. Some bacteria have a strong survival ability in semen and do not even die during cryopreservation. In the semen of infertile individuals, the number of bacteria accounts for about 30%. If the pathogenic bacteria are greater than 103/ml and non pathogenic bacteria are greater than 104/ml, it can lead to infertility.
Epididymitis is a common clinical disease. Most cases are secondary to urethral infections. The main pathogenic bacteria are Escherichia coli, Staphylococcus and Streptococcus, which are usually infected by ascending the vas deferens to the epididymis. Blood line infection is rare. The pathological changes of epididymitis are hyperemia and edema of epididymal duct epithelium, inflammatory exudate in the lumen, and then the formation of scar tissue, leading to epididymal duct obstruction. So bilateral epididymitis can lead to infertility. Male reproductive system tuberculosis, whether transmitted through the urethra or through blood, mostly causes lesions in the seminal vesicles and prostate, and then spreads to the epididymis through the vas deferens or lymphatic vessels, leading to epididymal tuberculosis. The pathological changes of epididymal tuberculosis often start from the tail and extend to the body and head. The epididymis is swollen and hard, and at the same time, the vas deferens are often thickened and hardened into a beaded shape. Therefore, bilateral epididymal tuberculosis often causes infertility.
3. Genital duct trauma can include trauma and surgical damage. Failure to repair urethral injuries often leads to obstruction of the vas deferens channel. Urethral injuries can be caused by straddling injuries, pelvic fractures, sharp instrument stabs, and improper use of various urethral instruments (such as urethral probes, metal catheter, cystoscope, lithotripsy forceps, or electroscope). Common injuries are to the urethral bulb and membrane, resulting in urethral stricture and obstruction, and inability to discharge semen. Pelvic, inguinal, and perineal surgeries can easily injure the vas deferens or spermatic cord, and failure to handle them in a timely manner can also lead to obstruction of the vas deferens passage.
(Intern Editor: Cai Junyi)
