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U N I T 1 1
Genitourinary and Reproductive Function
largely unsuccessful. It also is thought that nonbacterial
prostatitis may be an autoimmune disorder.
Men with noninflammatory prostatitis have symp-
toms resembling those of nonbacterial prostatitis but
have negative urine culture results and no evidence of
prostatic inflammation (i.e., normal leukocyte count).
The cause of noninflammatory prostatitis is unknown,
but because of the absence of inflammation, the search
for the cause of symptoms has been directed toward
extraprostatic sources. In some cases, there is an appar-
ent functional obstruction of the bladder neck near the
external urethral sphincter; during voiding, this results
in higher-than-normal pressures in the prostatic urethra
that cause intraprostatic urine reflux and chemical irri-
tation of the prostate by urine. In other cases, there is
an apparent myalgia (i.e., muscle pain) associated with
prolonged tension of the pelvic floor muscles. Emotional
stress also may play a role.
Treatment methods for chronic prostatitis/pelvic pain
syndrome are highly variable and require further study.
Antibiotic therapy is used when an occult infection is
suspected. Treatment often is directed toward symp-
tom control. In men with irritative urination symptoms,
α
-adrenergic blocking agents and/or 5
α
-reductase inhibi-
tors (such as finasteride) may be beneficial. Noncentered
treatment methods such as physical therapy, myofascial
trigger point release therapy, and relaxation techniques
may provide some symptom relief.
43
Benign Prostatic Hyperplasia
Benign prostatic hyperplasia (BPH), also called nodular
hyperplasia of the prostate, is a common age-related,
nonmalignant enlargement of the prostate gland
14,15,44–46
(Fig. 39-11). It has been reported that more than 50%
of men older than 60 years of age have BPH.
44
The dis-
order is seen most frequently in Europe and the United
States, and is seen least commonly in Asia.
15
The preva-
lence of the disorder in the United States is higher among
blacks than among whites.
Pathogenesis.
The pathogenesis of BPH is not com-
pletely understood, but appears to involve an imbalance
between cell proliferation and cell death that results in
an overgrowth of the mucosal glands of the prostate.
There is an increased number of epithelial cells and stro-
mal components of the periurethral area of the prostate,
but no clear evidence of increased epithelial cell prolif-
eration. Instead, it has been proposed that the cause of
the hyperplastic process is decreased cell death, result-
ing in an accumulation of senescent cells.
14
The main
androgen in the prostate is dihydrotestosterone (DHT),
which is formed in the prostate from the conversion of
testosterone by the enzyme 5
α
-reductase. It is thought
that DHT-induced growth factors increase the prolif-
eration of prostatic stromal cells and decrease the death
of the epithelial cells. The discovery that DHT is the
active factor in BPH provides the rationale for the use of
5
α
-reductase inhibitors in the treatment of the disorder.
Benign prostatic hyperplasia is characterized by the for-
mation of large, discrete lesions in the periurethral region
of the prostate rather than the peripheral zones, which
commonly are affected by prostate cancer (Fig. 39-12).
The anatomic location of the prostate at the bladder neck
contributes to the obstructive properties of BPH and
development of lower urinary tract symptoms. There are
two distinct components of the obstruction: static and
dynamic.
44,45
The static component of BPH is related to an
increase in prostatic size and gives rise to symptoms such
as a weak urinary stream, postvoid dribbling, frequency
of urination, and nocturia. The dynamic component of
BPH is related to prostatic smooth muscle tone, which
is mediated by
α
1
-adrenergic receptors. The recognition
of the role of
α
1
-adrenergic receptors on neuromuscular
function in the prostate is the basis for use of
α
1
-adrenergic
receptor blockers in treating BPH. A third component,
detrusor instability and impaired bladder contractility,
may contribute to the symptoms of BPH independent
of the outlet obstruction created by an enlarged prostate
(see Chapter 27). It has been suggested that some of the
symptoms of BPH might be related to a decompensating
or aging bladder rather than being primarily related to
outflow obstruction. An example is the involuntary con-
traction that results in urgency and an attempt to void
that occurs because of small bladder volume.
45
Clinical Course.
The clinical significance of BPH
resides in its tendency to compress the urethra and cause
partial or complete obstruction of urinary outflow. As
the obstruction increases, acute retention of urine may
occur with overdistention of the bladder. The resid-
ual urine in the bladder causes increased frequency of
urination and a constant desire to empty the bladder,
which becomes worse at night. With marked bladder
FIGURE 39-11.
Nodular hyperplasia of the prostate. Cut
surface of a prostate enlarged by nodular hyperplasia shows
numerous, well-circumscribed nodules of prostatic tissue.The
prostatic urethra (paper clip) has been compressed to a narrow
slit. (From Damjanov I, McCue PA.The lower urinary tract and
male reproductive system. In: Rubin R, Strayer DS, eds. Rubin’s
Pathology: Clinicopathologic Foundations of Medicine. 6th ed.
Philadelphia, PA: Wolters Kluwer Health | Lippincott Williams &
Wilkins; 2012:841.)
