Over the years I have seen many men with the absence of sperm in the ejaculate (azoospermia). Some went on to have children with IUI because they had retrograde ejaculation, some conceived with IVF/ICSI and others through donor sperm or adoption. The ability to conceive in spite of azoospermia is truly one of the medical miracles of the past 20 years. During medical school at Duke I took an elective in Reproductive Physiology. In that class we learned about the number of sequential steps required to ensure that normal fertilization took place. If I had ever raised my hand and said “Hey, why not take a single sperm, break its tail and ram it into the middle of the egg” I would have been laughed out of the classroom…and yet that is exactly what we do with ICSI. But before we launch into treatment, there should be some consideration given to why would a man’s sperm count be zero.
So with our investigative hats on, here is today’s “Question of the Day”:
33. What can cause my husband to have no sperm at all?
Assuming that there was not a problem in collecting the specimen, the absence of sperm on a semen analysis—a condition known as azoospermia—requires thorough evaluation. Azoospermia can be divided into two major categories: obstructive and nonobstructive. Obstructive azoospermia occurs when the duct carrying the sperm from the testicle to the urethra becomes blocked. This blockage may be the result of previous surgery on the scrotum or testicle, or even follow repair of an inguinal hernia. During such surgery, the vas deferens may have been inadvertently damaged or even cut. Scar tissue can also form either postoperatively or following an infection (most commonly gonorrhea, though other infectious diseases may also cause blockage of the sperm duct). Some men are born without a vas deferens on either side. This congenital bilateral absence of the vas deferens (CBAVD) is associated with the gene for cystic fibrosis. In other words, CBAVD is a rather unusual presentation of cystic fibrosis that occurs in the absence of any chronic lung disease. For this reason, any man with azoospermia associated with congenital absence of the vas deferens should undergo genetic testing to determine whether he carries the gene that causes cystic fibrosis. Nonobstructive azoospermia is the result of a dysfunction in sperm production and can represent a more problematic situation. The source of the production problem may be the result of either a testicular issue or a pituitary or hypothalamus issue causing a failure of sperm production in an otherwise normal testis. If a hormonal evaluation reveals normal levels of prolactin and thyroid hormone, then testicular sperm production may have failed. If this finding is associated with an elevated FSH level, then the chance of finding any sperm production in the testis is quite unlikely. A testicular biopsy can be performed to assess whether any sperm are present within the testis. Even very low levels of sperm production may allow for attempts at IVF using ICSI. Genetic testing to rule out a chromosomal problem is often suggested in cases of very low or absent sperm production.
mardi 12 juin 2007
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