Posttesticular Causes of Male infertility

POSTTESTICULAR

(

Table 42-14)

Reproductive Tract Obstruction

The posttesticular portion of the reproductive tract includes the epididymis, vas deferens, seminal vesicles, and associated ejaculatory apparatus.

A. Congenital Blockages
1. Cystic fibrosis - Cystic fibrosis (CF) is the most common autosomal recessive genetic disorder in the United States and is fatal. It is associated with fluid and electrolyte abnormalities (abnormal chloride-sweat test) and presents with chronic lung obstruction and infections, pancreatic insufficiency, and infertility. Interestingly, 98% of men with CF are missing parts of the epididymis. In addition, the vas deferens, seminal vesicles, and ejaculatory ducts are usually atrophic, or completely absent, causing obstruction. Spermatogenesis is usually normal. Congenital absence of the vas deferens (CAVD) accounts for 1-2% of infertility cases. On physical examination, no palpable vas deferens is observed on one or both sides. As in CF, the rest of the reproductive tract ducts may also be abnormal and unreconstructable. This disease is related to CF. Even though most of these men demonstrate no symptoms of CF, up to 65% of patients will harbor a detectable CF mutation. In addition, 15% of these men will have renal malformations, most commonly unilateral agenesis.

2. Young syndrome - Young syndrome presents with a triad of chronic sinusitis, bronchiectasis, and obstructive azoospermia. The obstruction is in the epididymis. The pathophysiology of the condition is unclear but may involve abnormal ciliary function or abnormal mucus quality. Although spermatogenesis is usually normal, reconstructive surgery is associated with lower success rates than that observed with other obstructed conditions.

3. Idiopathic epididymal obstruction - Idiopathic epididymal obstruction is a relatively uncommon condition found in otherwise healthy men. There is recent evidence linking this condition to CF in that one-third of men so obstructed may harbor CF gene mutations.

4. Adult polycystic kidney disease - Adult polycystic kidney disease is an autosomal dominant disorder associated with numerous cysts of the kidney, liver, spleen, pancreas, epididymis, seminal vesicle, and testis. Disease onset usually occurs in the twenties or thirties with symptoms of abdominal pain, hypertension, and renal failure. Infertility with this disease is usually secondary to obstructing cysts in the epididymis or seminal vesicle.

5. Blockage of the ejaculatory ducts - Blockage of the ejaculatory ducts, the delicate, paired, collagenous tubes that connect the vas deferens and seminal vesicles to the urethra, is termed ejaculatory duct obstruction. It is the cause of infertility in 5% of azoospermic men. Obstruction can be congenital and result from mullerian duct (utricular) cysts, wolffian duct (diverticular) cysts, or congenital atresia or is acquired from seminal vesicle calculi or postsurgical or inflammatory scar tissue. It presents as hematospermia, painful ejaculation, or infertility. The diagnosis is confirmed by finding a low-volume ejaculate and TRUS showing dilated seminal vesicles or dilated ejaculatory ducts.

B. Acquired Blockages
1. Vasectomy - Vasectomy is performed on 750,000 men per year in the United States for contraception. Subsequently, approximately 5% of these men have the vasectomy reversed, most commonly because of remarriage.

2. Groin and hernia surgery - Groin and hernia surgery can result in inguinal vas deferens obstruction in 1% of cases. There has been concern that Marlex mesh used for hernia repairs may add to perivasal inflammation and increase the likelihood of vasal obstruction.

3. Bacterial infections - Bacterial infections (E coli in men age > 35) or Chlamydia trachomatis in young men) may involve the epididymis, with scarring and obstruction.

C. Functional Blockages
Besides physical obstruction, functional obstruction of the seminal vesicles may exist. Functional blockages may result from nerve injury or medications that impair the contractility of seminal vesicle or vasal musculature. A classic example of nerve injury affecting ejaculation is after retroperitoneal lymph node dissection for testis cancer. This can cause either retrograde ejaculation or true anejaculation, depending on the degree of injury to postganglionic sympathetic fibers arising from the thoracolumbar spinal cord. These autonomic nerves overlie the inferior aorta and coalesce as the hypogastric plexus within the pelvis and control seminal emission. Multiple sclerosis and diabetes are other conditions that result in disordered ejaculation.

Evidence from animal models indicates that the seminal vesicles, lined by smooth muscle, possess contractile properties similar to those of the urinary bladder, making it conceivable that seminal vesicle organ dysfunction may underlie some cases of ejaculatory duct “obstruction.” Medications implicated in this functional problem are those classically associated with ejaculatory impairment.

Table 42-5 lists these medications.

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Provided by ArmMed Media
Revision date: July 8, 2011
Last revised: by Sebastian Scheller, MD, ScD