C h a p t e r 2 7
Disorders of the Bladder and Lower Urinary Tract
671
potassium chloride solution and sterile water directly
into the bladder. Increased pain with instillation of the
potassium solution is considered a positive test and indi-
cates urothelium dysfunction.
There are a wide array of treatment options for inter-
stitial cystitis/painful bladder syndrome.
55,56
Pentosan
polysulfate sodium is the only FDA–approved oral ther-
apy for the treatment of interstitial cystitis. The drug,
which is an antidepressant, is thought to facilitate repair
of the urothelium. Hydroxyzine (Vistaril), which is
thought to control mast cell degranulation, and amitrip-
tyline or nortriptyline, which inhibit neural activation,
may also be used. Other nonspecific oral medications,
such as analgesics, anti-inflammatory agents, and the
urinary anesthetic phenazopyridine (Pyridium), can be
used. Anticholinergic drugs are frequently used to con-
trol pain and frequency.
Cancer of the Bladder
Cancer of the bladder is the sixth most common malig-
nancy in the United States, accounting for 7% of can-
cers in men and 3% of cancers in women.
57–60
For some
as-yet unexplained reason, African Americans have only
half the risk of white European Americans. Most cancer
of the bladder occur in older persons and is rare in those
under the age of 50 years.
Approximately 90% to 95% of bladder cancers are
derived from the transitional epithelial (urothelial) cells
that line the bladder.
57–60
These tumors can range from
benign papillomas and low-grade papillary urothelial
carcinomas to invasive urothelial cell carcinomas and
highly malignant tumors.
Urothelial papillomas are rare benign tumors, of
which there are two forms: exophytic papillomas and
inverted papillomas.
59,60
Exophytic papillomas
have
fonts or finger-like papillae with a central core of loose
fibrovascular tissue covered by epithelium. Although
considered benign some exophytic papillomas may
recur or progress to carcinoma, thus long-term follow-
up is necessary after excision.
Inverted papillomas
are
benign nodular lesions that are cured by excision.
Papillary urothelial neoplasms of low malignant
potential share many histologic features with papillo-
mas; however, they have a thicker urothelium and dif-
fuse nuclear enlargement (Fig. 27-5). They may recur
after excision and only rarely recur as higher grade
tumors associated with invasion and progression.
59,60
Low-grade papillary urothelial carcinomas have fonts
Urethra
Ureter
Dome 10%
Posterior and
lateral wall
70%
Trigone and
bladder neck
20%
Localization
Type
Papillary 80%
Carcinoma
in situ 3%
Papilloma
Papillary and
invasive
Flat invasive
Flat
noninvasive
FIGURE 27-5.
Urothelial neoplasms. Most tumors are located
on the posterior and lateral walls; trigone and bladder neck are
involved less commonly. Malignant tumors may be papillary
or flat. Both flat and papillary tumors may be invasive or
noninvasive. Benign transitional cell papillomas are rare.
(Adapted from Damjanov I, McCure 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; 2012:819.)
SUMMARY CONCEPTS
■■
Urinary tract infections (UTIs) include several
distinct entities, including asymptomatic
bacteriuria, symptomatic lower UTIs such as
cystitis, and upper UTIs such as pyelonephritis.
■■
UTIs involve host–agent interactions in which
the defenses of the host compete with those
of the infectious agent. Host defenses include
the washout phenomenon in which the flow
of urine washes bacteria out of the urethra,
the bacteriostatic properties of the urine, the
protective mucin layer that lines the bladder,
and the antimicrobial properties of the normal
periurethral flora in women and prostate
secretions in men. Pathogen virulence derives
from its ability to gain access to and thrive in the
environment of the urinary tract, to evade the
destructive effects of the host’s immune system,
and to develop resistance to antimicrobial agents.
■■
Most UTIs ascend from the urethra and bladder.
A number of factors interact in determining the
predisposition to development of ascending UTIs,
including urinary tract obstruction, urine stasis
and reflux, pregnancy-induced and aging changes
in urinary tract function, and presence of urinary
tract catheters.
■■
Interstitial cystitis or painful bladder syndrome
is a chronic, often debilitating, condition that
is characterized by urinary frequency, urgency,
and severe suprapubic pain. Unlike bladder
inflammation caused by a bacterial infection,
the condition occurs in the absence of other
pathology.
