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.