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Lower urinary tract. The lower urinary tracts consists of the ureters, urinary bladder and the urethra. These organs are involved in the involuntary storage of urine produced in the upper urinary tract and the voluntary expulsion of urine at an appropriate time and place.
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LOWER URINARY TRACT. Ureter, bladder & urethra.
By: Abiodun Mark Akanmode Lower urinary tract. The lower urinary
tractsconsists of the ureters,urinary bladder and theurethra. These
organs are involvedin the involuntary storage ofurine produced in
the upperurinary tract and thevoluntary expulsion of urineat an
appropriate time andplace. Lower urinary tract There are
considerable variations in theanatomy of the male and female
urinarytract but we focus our attention on the malelower urinary
tract. A thorough knowledge and understanding ofthe relevant
anatomy is essential inunderstanding the variouspathophysiological
mechanisms of LUTdisorders and their appropriate management Ureter.
The ureter is a tubular structure ,30cm in lengthand 0.5cm in
diameter. It extends from the renal pelvis to the urinarybladder.
The ureters enter the bladder in an obliquely, sothat its
compressed during micturition to preventvesico-ureteric reflux. The
ureter is lined by transitional epitheliuminternally and by a
fibrous layer which ensheathsthe muscular layers. Double &Bifid
ureter. This is a condition inwhich the upper or theentire part of
theureter is duplicated. Double ureter isassociated with
doublerenal pelvis. Most cases areunilateral & of noclinical
significance. Ureteric diverticular.
This is a very rarecongenital disorder ofthe ureter. It is
characterized bythe presence ofsaccularoutpouchings of theureteral
wall. Ureteral Tumors & tumor like lesions
Primary tumors of the ureter are very rare. However the malignant
tumors of the ureterresemble those arising from the renal
pelvis,calyces and bladder. Most of the malignant lesions of the
ureter areurothelial carcinomas. Urothelial carcinomas are
predominant betweenthe 6th and 7th decades. Obstructive lesions of
the ureter.
Variouspathologic lesions can lead to ureteral obstructionthus
giving rise to hydroureter, hydronephrosisandoccasionally
pylelonephritis. Sclerosing retroperitoneal fibrosis(RPF):This is
anuncommon cause of ureteral narrowing/obstructioncharacterized by
a fibrous proliferation aroundretroperitoneal structures eventually
leading tohydronephrosis. The idiopathic variant of this disease
i.e. idiopathicretroperitoneal fibrosis is also called Ormond's
disease. N.B:Ormond's disease may present withlower back
pain,kidney failure,hypertension,deep vein thrombosis, and other
obstructive symptoms Other causes of ureteral obstruction.
Intrinsic causes:-calculi/stone.-Strictures.-Blood clots. Extrinsic
causes: -Pregnancy.-Endometriosis.-Tumors. Urinary bladder.
Theurinary bladderis the organ thatcollectsurineexcreted by the
kidneysbeforedisposal byurination. The bladder lies
extraperitoneallyand theperitoneal surface is reflected on its
superiorsurface. The greater part of the bladder wall is made up
ofdextrusor muscles while the bladder trigone is aprolongation of
the muscle layers from eachureter. Congenital bladder
anomalies.
Bladder or vessical diverticulum: This consists ofa pouch-like
evagination of the bladder wall. Diverticulum could be acquired or
congenital. Congenital diverticulumis mostly ascribed tofocal
failure in the normal musculaturedevelopment. Acquired diverticulum
is associated withprostatic enlargement & obstruction to
urineflow. Although most diverticulum are small areinsignificant
they might constitute a site ofstasis(urine), hence infection and
sepsis. Bladder diverticulum. BLADDER EXTROPHY. In bladder
extrophydevelopmental defectsin the anteriorabdominal wall
allowsfor a communicationof the bladder withthe exterior. The
exposed bladderis highly susceptibleto infections. Cystitis. This
refers to the inflammation of the urinary bladder.
The common etiologic agents implicated incystitis are E.coli,
proteus, klebsiella andenterobacter. Women are more predisposed to
developingcystitis as compare to males because of theirshorter
urethras. Triad of cystitis is: frequency, lower abdominalpain and
dysuria. Morphology: acute cystitis.
Grossly: Acute cystitis ischaracterized by a swollen,red and
hemorrhagic bladder mucosa. There may be suppurativeexudatesor
ulcer also onthe bladder mucosa. Microscopically acutecystitis is
characterized byintense neutrophilicexudation admixed
withlymphocytes andmacrophages. Morphology: chronic cystitis.
Repeated attacks of acute cystitis lead to chroniccystitis.
Grossly: The mucosal epithelium is thickened, redand granular with
polypoid masses. long standingcases gives rise to a thickened
bladder wall andshrunken cavity. Microscopically: There is a patchy
ulceration of themucosa with the formation of granulation tissue.
Follicular cystitis. This is a type ofcystitischaracterized bythe
aggregation oflymphocytes intolymphoid follicleswithin the
bladdermucosa and wall. Follicular cystitis isnot
necessarilyassociated with abacterial infection. Special types of
cystitis: Interstitial cystitis.
Interstitial cystitis(chronic pelvic painsyndrome):This is a
persistent, painfulform of chronic cystitis occurring mostlyin
women. The etiology of which is unknown. Some pt with this
condition show chronicmucosal ulcers (Hunner ulcers). Late in this
disease, there is transmuralfibrosis leading to a contracted
bladder . Interstitial cystitis is characterized bysuprapubic pain,
hematuria, dysuria,frequency without evidence of
bacterialinfection. Interstitial cystitis
Interstitial cystitisgiving rise to acontracted bladderappearance.
Special types of cystitis: malacoplakia.
This are soft ,flat yellowish lesionsfound on the surface of the
bladdermucosa. They tend to vary from 0.5-5cm indiameter. They are
composed of large amountsof foam macrophages, multinucleatedgiant
cells and lymphocytes. Malacoplakia is also characterized bythe
presence of Michaelis-Gutmannbodies. M-G bodies:
Areroundedlaminatedbodies
containingcalciumandironandfoundwithinmacrophagesinthe
bladderwallinmalacoplakia. Special types of cystitis: polypoid
cystitis.
This is usually secondary to the irritation of thebladder wall. Its
characterized by papillary projections on thebladder mucosa.
Indwelling catheters are usually responsible forthis variant of
cystitis. Polypoid cystitis may be confused for papillaryurothelial
carcinoma clinically & histologically. Metaplastic lesions of
the bladder.
Cystitis glandularis & cystitis cystica:Here nest (Brunn nests)
of transitionalepithelium grows downwards into thelaminar propria
and undergoes
transformationintocubiodalorcolumnarepitheliumlining(c.glandularis)
or cystic spaces (c.cystica) Both variants are common
microscopicfindings in a relatively normalbladder. Squamous
Metaplasia: injury to theurothelium is often replaced by squamous
epithelium. Bladder neoplasm's. Bladder cancer accounts for 7% of
cancer in theUS. About 95% of bladder cancers are of the
epithelialorigin with the rest been of the mesenchymalorigin. Most
epithelial bladder cancers are of theurothelial
(transitional)origin. Urothelial/transitional tumors.
They account for 90% of all bladder cancers. The 2 major precursor
lesions to invasiveurothelial carcinoma are:-non-invasive papillary
tumors.-flat non invasive urothelial carcinoma(CIS). In about 1/3rd
of pt with bladder ca, the cancerhas already invaded the bladder
wall at the timeof presentation and no precursor lesion would
beseen. Morphology of urothelial tumors. :
The gross pattern ofurothelial tumorstends to vary frompapillary to
nodular orflat. 90% of all urothelialtumors are papillary. Most
papillary tumorsare low grade andarise from the lateralor posterior
wall of thebladder. Low grade papillary urothelial carcinoma
Low grade papillaryurothelial carcinoma:characterized by
orderlyappearancearchitecturally andcytologically. They tend to
recur andthey seldomly invade. B Image A: Noninvasive low-grade
papillary urothelial carcinoma. Higher magnification (right) shows
slightly irregular nuclei with scattered mitotic figures (arrow).
Image B: normal bladder showing the transitional epithelium. High
grade papillary urothelial cancer:
This variant containscells that are morearchitecturally indisarray,
areas of largeshyperchromasia seen,abundant mitotic figuresetc. 80%
of high gradetumors are invasive. A:High grade urothelial carcinoma
with marked atypical. B:Cystoscopic appearance of a papillary
urothelial tumor, resembling coral, within the bladder. C:High
grade invasive papillary ca. Bladder cancer epidemiology.
Several factors have been implicated in theetiology of urothelial
cancers such as:-Cigarette smoking.-Industrial exposure to
napthalamine.-Parasitic infection with shistosoma
hematobium.-Drugs: cyclophosphamide etc.-Diet.-Local lesions.-Prior
exposure to radiation.-Long term analgesic use. Clinical features
of bladder tumors.
Bladder tumors classically produces painlesshematuria. Urgency,
frequency and dysuria occasionallyaccompany the hematuria.
Treatment for bladder tumors depends on thestage and whether its a
flat of papillary lesion. Chemotherapy and radical cystectomy are
bothproven ways to manage bladder tumors. Bladder obstruction.
Obstruction of the bladder neck eventuallycauses problems with the
kidney. Bladder obstruction in males is mostly due tonodular
prostatic hyperplasia. Other causes of bladder obstruction
include:-Congenital urethral stricture.-Inflammatory urethral
strictures.-Bladder tumors.-Mechanical obstruction by foreign body
or calculi.-Neurogenic bladder. MORPHOLOGY OF BLADDER
OBSTRUCTION.
There ishypertrophy& thickeningof the smoothmuscle of
thebladder wall. NB: image shown above demonstrate hypertrophy and
trabeculations of the bladder wall secondary to polypoidhyperplasia
of the prostate. URETHRA. The urethra runs from the bladder up to
the external meatus.
The male urethra has 3 major parts-prostatic,membranous and penile.
The female urethra is much shorter than themale urethra. The
urethra functions to convey urine from thebladder and also as a
passage way for varioussecretions from reproductive organs.
Urethritis. This is the inflammation of the urethra.
Urethritis is divided into gonococcal and nongonococcalurethritis.
The bacteria's involved in NGU include E.coli,Chlamydia etc.
Urethritis is a component of the REITERSSYDROME which comprises of
arthritis,conjuctivitis and urethritis. Tumors & tumor-like
lesions of the urethra.
URETHRALCARUNCLE: this is aninflammatory lesionthat presents as
asmall painful massaround the urethralmeatus. its commonin older
females. PRIMARY CARCINOMAOF THE URETHRA: thisis an uncommon
lesion,but are mostly ofsquamous cell origin.