The outflow tract causes for abnormalities in sperm include
* (1) Congenital absence of the vas deferens (CAVD)
CAVD is an uncommon obstructive post testicular lesion that results
in a complete absence of sperm (azoospermia). Most men with CAVD
have an intact upper one third to two thirds of the epididymis.
This allows normally produced sperm to be collected within this
storage depot. CAVD occurs in up to 95% of men with cystic fibrosis
(a serious autosomal recessive gene disorder of mucus production
that affects several organ systems including the lungs). Up to
50% of men who have only one gene mutation for cystic fibrosis
(especially the mutation referred to as the delta 508 mutation)
will have CAVD. These men are carriers of the cystic fibrosis
trait but do not have clinical cystic fibrosis since this disease
requires the presence of 2 gene mutations
* (2) Retrograde ejaculation into the bladder
This can occur if the bladder neck will not close during emission
An interruption in the sympathetic nerve supply to the pelvic
area can result in retrograde ejaculation. This may occur with
some medications that affect the nervous system, following radical
regional surgery that might damage the nerves like retroperitoneal
lymph node dissection for testicular cancer, or with some systemic
illnesses that can effect the integrity of these nerves such as
diabetes mellitus and multiple sclerosis. Prior reconstructive
bladder surgery can also result in retrograde ejaculation. This
may occur after Y-V plasty of the bladder neck at the time of
reimplantation of the ureters as a child (popular in the 1960s)
or TransUrethral Resection of the Prostate ("TURP").
* (3) Epididymitis
Storage of sperm in an infected epididymis can reduce sperm quality.
If suspected, daily ejaculation to reduce the storage time can
occasionally be useful.