Lower Urinary System Anatomy PDF

CHAPTER 11 THE LOWER URINARY SYSTEM Dana C. Walker and Sara M. Baker Copyright © 2018 Wolters Kluwer All Rights Res erved Copyright © 2014 Wolters Kluwer All Rights Reserved The Lower Urinary System: Introduction Overview of the Urinary System Kidneys are part of...

CHAPTER 11 THE LOWER URINARY SYSTEM Dana C. Walker and Sara M. Baker Copyright © 2018 Wolters Kluwer All Rights Res erved Copyright © 2014 Wolters Kluwer All Rights Reserved The Lower Urinary System: Introduction Overview of the Urinary System Kidneys are part of superior urinary system Ureter, bladder, and urethra form lower urinary system and play important roles in transporting, storing, and eliminating urine Pelvic ureter and urethra are conduits in process of elimination of urine Urinary bladder is located anatomically between ureter and urethra and functions as a reservoir for urine storage Copyright © 2018 Wolters Kluwer All Rights Reserved The Lower Urinary System: Introduction Overview of the Urinary System Normal pelvic ureter and urethra are not usually seen sonographically Structures may be visualized with coexisting pathologic conditions Urine-filled bladder is an accessible abdominopelvic organs for sonography exam Recognition of normal bladder anatomy, including position, size, shape, and appearance helps identify congenital anomalies, pathologies, and abnormalities in surrounding anatomy Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Embryological Development During early embryology of urogenital system, kidneys develop in 3 successive waves from cranial to caudal: 1. Pronephros—early in 4th embryologic week 2. Mesonephros—late in 4th week 3. Metanephros—5th week Third most inferior pair of kidneys (metanephros) becomes permanent kidneys Caudal end of hindgut has cloaca—a dilated chamber Cloacal endoderm is in close contact with surface ectoderm and together they form cloacal membrane Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Embryologic Development An extension from cloaca into umbilical cord is the allantois Intermediate mesoderm of gastrula bulges into dorsal aspect of the intraembryonic coelom as a urogenital ridge on each side Ridge further develops into two ridges: 1. Medial genital (gonadal) ridge and 2. Lateral nephrogenic ridge (or cord) Mesonephric (Wolffian) duct and paramesonephric (Müllerian) duct form in nephrogenic ridge or cord Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Embryologic Development Approximately in the 7th gestational week, urorectal septum between allantois and hindgut fuses with cloacal membrane to divide it into ventral (anterior) urogenital sinus and dorsal (posterior) rectum Upper part of urogenital sinus is fusiform bladder Lower pelvic and phallic parts of urogenital sinus form the urethra and related glands and structures in each sex (female or male) Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Embryologic Development Wolffian ducts give rise to the ureters, and they also form in: Females Males  Epoophoron  Efferent tubules  Paroophoron  Duct of epididymis  Gartner’s duct  Vas deferens  Seminal vesicles Ends of mesonephric ducts (Wolffian and Müllerian)  Ejaculatory ducts and endodermal cloaca form urinary bladder Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Embryologic Development Cloaca—terminal, caudal, blind-ended portion of hindgut Major structure that forms lower part of urinary and genital tract Primary function—serves as primitive receptacle into which reproductive and excretory tracts empty Metanephric duct (future ureter) develops from a ureteric bud growing from caudal end of mesonephric duct In a short time—metanephric duct shifts anteriorly and makes its own connection with cloaca/urogenital sinus/bladder Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Embryologic Development—8 Weeks Gestation In females: mesonephric (Wolffian) ducts degenerate Paramesonephric ducts develop into uterine tubes, uterus, and upper part of vagina Urogenital sinus forms bladder, urethra, greater vestibular and paraurethral glands, vestibule, and lower part of vagina Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Embryologic Development—8 Weeks Gestation In males: paramesonephric (Müllerian) ducts degenerate Mesonephric ducts become ductus deferens, ejaculatory ducts, and seminal vesicles Urogenital sinus develops into urinary bladder, prostate gland, bulbourethral glands (Cowper’s gland), paraurethral glands, prostatic, membranous, and penile (spongy) urethra Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Embryologic Development Initially bladder is contiguous with allantois, which eventually becomes a fibrous cord—urachus (known as median umbilical ligament in adult) Urachus extends from bladder apex to umbilicus In infants and children, urinary bladder is an abdominal organ until after puberty when it becomes a true pelvic structure Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Urinary Bladder Bladder develops into a hollow, smooth, musculomembranous, collapsible sac that acts as a reservoir for urine It is located in retroperitoneum on pelvic floor just posterior to pubic symphysis Its size, position, and relationship to other organs vary according to the amount of fluid it contains Bladder is lined with a mucous membrane of transitional epithelium that allows for expansion Mucous membrane lining contains rugae or folds When bladder is empty, membrane appears folded or wrinkled Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Urinary Bladder Mucous membrane is loosely attached to underlying muscle coat except at trigone region where it is firmly attached to muscular coat, appears smooth, and does not expand during bladder filling Capable of considerable distention—lining’s elasticity and rugae and wall’s elasticity Capacity varies greatly and depends on many factors, including age and physical condition Normal adult bladder is generally moderately full at 500 mL (a pint) of urine but may hold nearly double if necessary Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Urinary Bladder Normally, bladder is a round-edged tetrahedron with a superior, a posterior, and two inferior surfaces Superior surface has two regions: 1. Fundus—located posteriorly 2. Apex—located anteriorly Two ureteral orifices are located in body on posteroinferior portion. Urethral orifice is located in neck of bladder and is most inferior region When bladder is empty—anterior surface lies just behind and rarely, superior to symphysis in both males and females Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Urinary Bladder Fibrous medial umbilical ligament (obliterated urachus) extends from apex upward as a blunt cone with a solid, slender continuation in midline of abdominal wall and attaches to umbilicus When distended with urine—bladder can rise approximately 16 cm above symphysis pubis Ascends into abdominal cavity Comes in contact with the lower anterior abdominal wall When fully distended it can be readily palpated or percussed As bladder enlarges, it loses ovoid or spherical configuration and becomes more globular Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Urinary Bladder Small intestine coils lie adjacent to upper surface of bladder and are displaced posteriorly as bladder enlarges Lower abdomen may visibly bulge with overdistention (acute/chronic urinary retention) Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Urinary Bladder In female, relative empty bladder fundal region lies in contact with anterior wall of vagina and cervix Uterus and vagina are interposed between bladder and rectum When bladder is empty, uterus rests on bladder’s superior surface Female reproductive and pelvic muscular anatomy is greatly enhanced using the traditional full-bladder technique Copyright © 2018 Wolters Kluwer All Rights Reserved Normal Female Anatomy Liver Liver Aorta Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Urinary Bladder In male, bladder fundus and body are related to rectum, separated above by the rectovesical pouch of peritoneum and inferolaterally on each side by a ductus deferens and seminal vesicle Prostate is a fibromuscular and glandular organ that lies just inferior to bladder Base of prostate is applied to caudal surface of bladder Greater part of caudal surface is directly continuous with bladder wall Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Urinary Bladder Normal prostate encircles prostatic urethra and prostate gland secretion enters prostatic urethra via several ducts Seminal vesicles lie just cephalad to prostate under base of bladder Seminal vesicles are approximately 6 cm long and quite soft Each vesicle joins its corresponding vas deferens to form ejaculatory duct Copyright © 2018 Wolters Kluwer All Rights Reserved Normal Male Anatomy Liver Liver Aorta Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Urinary Bladder—Trigone Trigone located on bladder floor as a triangular region Has no rugae Firmly attached to muscular coat Trigone is outlined by three openings in bladder: 1. Two from ureters 2. One into urethra Ureteral orifices are situated superiorly and laterally at extremities of crescent-shaped interureteric ridge that forms proximal border of trigone Urethral opening is located at its anterior, midline, lower corner at bladder neck Copyright © 2018 Wolters Kluwer All Rights Reserved Trigone  Three-dimensional rendered image of bladder trigone demonstrating ureteral and urethral openings (arrows).  Image of inner bladder lining provides a virtual cystogram of bladder wall. Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Ureters Ureters are slender tubes that convey urine from kidneys to bladder Each ureter is a continuation of the renal pelvis. From renal pelvis, ureters descend in retroperitoneum and course obliquely through posterior bladder wall Average ureter length is 30 cm and diameter is 6 mm Ureters are constricted in three locations: 1. At ureteropelvic junction 2. As they cross the iliac vessels 3. At junction with bladder Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Ureters As bladder fills, the pressure increases causing upper and lower walls of terminal portions of ureter to become closely applied to each other to act as valves to prevent regurgitation of urine from bladder When bladder is distended, the openings of ureters are about 5 cm apart, and distance between them is diminished by half when bladder is empty and contracted Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Urethra Urethra is a thin-walled fibromuscular tube that drains urine from bladder and conveys it outside the body Urethra represents terminal portion of urinary tract At bladder–urethral junction, a thickening of detrusor smooth muscle of bladder wall forms the internal urethral sphincter Detrusor muscle is involuntary and keeps urethra closed to prevent leaking between voiding Sphincter is unique in that contraction opens it and relaxation closes it Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Urethra External urethral sphincter surrounds urethra as it passes through urogenital diaphragm Urethral sphincter is skeletal muscle and is controlled voluntarily Length and functions of urethra differ in males and females Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Urethra—Females Urethra is 3 to 4 cm long and functions only to convey urine from the body Located directly posterior to symphysis pubis and anterior to vagina External urethral orifice is the external opening of urethra and is located anterior to vaginal opening and posterior to clitoris Urethral opening to exterior is referred to as urinary meatus Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy and Organogenesis Urethra—Males Urethra serves a double function: 1. Conduit for eliminating urine 2. Terminal portion of reproductive system serving as passage for ejaculate (semen) Approximately 20 cm long and has 3 regions 1. Prostatic urethra is about 2.5 cm long and courses within prostate 2. Membranous urethra courses through urogenital sinus, extends about 2 cm from prostate to the beginning of penis 3. Spongy urethra passes through penis and opens at its tip—external urethral orifice Copyright © 2018 Wolters Kluwer All Rights Reserved Quiz What is the normal location of an empty urinary bladder? A. Posterior surface is superior to the symphysis B. Anterior surface is located behind the symphysis C. Overdistended at 250 mL rising superiorly in abdomen D. Superior to uterus or superior to prostate Copyright © 2018 Wolters Kluwer All Rights Reserved Quiz How many weeks gestation do all embryos have identical primordia in the indifferent stage of urogenital development with gonads capable of developing into testes or ovaries? A. 8 weeks B. 9 weeks C. 10 weeks D. 11 weeks Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Micturition is mechanism for voiding urine and starts with involuntary and voluntary nerve impulses When volume of urine exceeds 200 to 400 mL, stretch receptors trigger transmission of impulses to lower portion of spinal cord, initiating conscious desire to expel urine and a subconscious, micturition reflex Combination of voluntary relaxation of external bladder sphincter muscle, reflex contraction of linear smooth muscle fibers along urethra, and then contraction of detrusor muscle squeezes urine out of bladder Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Parasympathetic fibers transmit impulses causing contractions of bladder and relaxation of internal sphincter Because external sphincter is under voluntary control, most people can choose to postpone bladder emptying Voluntary contraction of external sphincter to prevent or terminate micturition is learned and is possible only if nerves supplying bladder and urethra (projection tracts of cord and brain) and motor area of cerebrum are all intact Incontinence—involuntary emptying of bladder Results from aging or trauma to any parts of nervous system by cerebral hemorrhage or cord injury Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Retention is inability to empty bladder even though bladder contains an excessive amount of urine Catheterization may be used to relieve discomfort accompanying retention 30% of patients who are routinely catheterized eventually develop a “ledge” posteriorly at bladder neck from catheter trauma Ledge makes voiding difficult and considerably complicates catheterization process Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Patient Preparation Important patients prepare properly to visualize bladder with transabdominal approach Bladder distention is absolutely essential to optimal visualization of bladder, bladder wall, and related anatomy Three methods can be used for bladder filling: 1. Instruct patient to drink 16 ounces of water 1 hour before exam and not to void until exam is completed 2. Instruct patient not to void before examination or 3. Catheterizing patient and instilling fluid into bladder through a Foley catheter Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Patient Preparation Foley catheters are not routinely inserted for bladder filling unless it is a medical emergency Many studies show catheter insertion may introduce infectious contaminants into body Foley catheter balloon appears as round cystic structure in filled bladder and may cast shadows in areas of interest Sonographically, fully distended bladder serves: As cystic reference in abdominopelvic anatomy Pushes adjacent bowel and gas out of field of view Provides “window” to identify pelvic anatomy Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Patient Preparation In males: bladder, seminal vesicles, prostate, and rectum should be imaged routinely In females: vagina, bladder, uterus, ovaries, adnexa, and rectum should be imaged routinely Full bladder also facilitates identification of dilated ureters Not necessary to restrict diet or use catheters or enemas to reduce intestinal contents or air Disease processes in pelvic structures can involve or mimic those of other closely related anatomy Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Patient Preparation Knowledge of pelvic anatomy, genitourinary tract, gastrointestinal tract, pelvic vasculature, and pelvic musculature are important Use suitable coupling agent on skin surface Transducer selection should take into consideration body habitus and exam objectives Select highest frequency transducer possible to make sure penetration is adequate to visualize posterior aspect of areas of interest Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Most widely used approach to scan the urinary bladder is transabdominal method. Patient is usually examined in supine position May be necessary to position patient obliquely or roll patient into lateral decubitus position to better demonstrate bladder wall abnormalities, movement of debris or calculi to dependent bladder wall, or bladder tumors To lesser extent, endovaginal, endorectal, and transperineal methods may be used for lower urinary tract Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Lower urinary system should be scanned in both longitudinal and transverse planes transabdominally, and may be scanned in longitudinal and coronal planes endovaginally and transperineally Using endorectal approach, proximal urethra can be visualized and distal urethra is identified during penile artery evaluation Recent studies have used an endorectal approach to evaluate female urogenital disorders such as stress incontinence Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Pathologically thickened bladder wall is better visualized when bladder is fully distended Interrogate for pathologic process if bladder wall is >6 mm when empty or partially distended When bladder is scanned transabdominally, reverberation echoes often are seen in near field of bladder image Reverberations, side lobes, and shadowing artifacts can be decreased or eliminated by: Using system controls and/or Altering transducer position to change angle of transmitted sound to avoid refraction from abdominal musculature Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Equipment instrumentation includes harmonics, speckle reduction, spatial compounding, and computerized techniques to aid elimination of artifact echoes Normal ureters and urethra are not routinely visualized on transabdominal sonography Location should be examined because anatomy can be identified in some anomalies, diseases, and pathologic processes Sonographer should identify predictable contours of urine-filled bladder and smooth echogenic bladder wall Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques If patient never had bladder or pelvic surgery, any deviation from normal bladder shape, especially asymmetry, should be considered abnormal Thorough investigation should be performed of site of distortion to rule out a mass Transverse sections: bladder should appear symmetric Superiorly, bladder appears rounded In scanning more inferiorly, bladder appears square owing to parallel walls of acetabulum Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Longitudinal sections: bladder appears almost triangular, with base of triangle parallel with anterior abdominal wall In both longitudinal and transverse scans, lateral walls appear straight or slightly indented by prominent iliopsoas muscles As different pelvic structures are encountered, it may be necessary to angle transducer caudad and cephalad and medial to lateral Symphysis pubis: point reference of body surface where transducer can be rocked superiorly and inferiorly on longitudinal scans to better view superior and inferior bladder aspects Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Transverse imaging must include tilting or a cross- plane imaging angling transducer from side to side while continuing to use fluid in bladder as a window This produces a sharper bladder wall image and gives a complete sweep to interrogate entire bladder Longitudinal and transverse images are easier to interpret if presented in sequential order: Longitudinal: Right-to-left with midline image identified Transverse: inferior to superior Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Correctly label all images indicating: Location of scan Patient position Scanning plane Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Frequently, it is possible to visualize prostate and seminal vesicles in males using transabdominal approach When transducer is angled caudad under symphysis pubis, prostate is seen posteroinferior to bladder On a longitudinal scan, prostate appears as heterogeneous structure at most inferior aspect of bladder On a transverse image, prostate appears rounded Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Newer transducers have better penetration and resolution to enable identifying prostate transabdominally in adult male Best way to visualize prostate is by way of endorectal approach Seminal vesicles are seen as two small, oval, hypoechoic structures posterior to bladder and superior to the prostate Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques In patients who are catheterized, catheter has an anechoic appearance with echogenic margin and center If air was used to secure the catheter’s position, it may cause a shadow artifact Sonographically, symmetry of catheter is identifiable as echogenic incomplete circular structure in urine- filled bladder Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Ureteral Jet Phenomenon Echo bursts entering bladder from trigone Interval of 5 to 20 seconds Jet of low-intensity echoes lasts a few seconds starts at area of ureteral orifices and flows toward center of bladder Ureteral jets can occur simultaneously More commonly jets are separated Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Ureteral Jet Phenomenon Jets can be individually identified on longitudinal images but both may be seen simultaneously on a transverse image Such jets extend up to 3 cm and broaden After a few seconds, low-intensity echoes become distributed in bladder and lose intensity until they can no longer be distinguished Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Ureteral Jet Phenomenon—Color Doppler Color Doppler is more sensitive and aids in demonstrating ureteral jets Evaluation of ureteral jets cannot predict reflux Analysis of ureteral jets is used successfully to determine degree of ureteral obstruction with unilateral ureteral calculi Ureteral obstruction with either no detectable ureteral jets or continuous low-level jets on symptomatic side Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Bladder diverticulum Evidence of reversed flow of urine through communication between diverticulum and bladder when slight pressure is applied to lower abdomen Dilated ureters: Transverse plane: If either ureter is dilated, it can be visualized as a round, anechoic structure posterior to bladder in transverse plane Longitudinal plane: dilated ureter can be visualized as a long, linear structure, usually posterior and to right or left of midline Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Bladder volume: Can be calculated using formula for an ellipsoid Transverse × Anteroposterior [AP] × Length × 0.52 Scanning equipment usually has computerized techniques to calculate volumes Systems will calculate bladder volume once the three measurements have been entered Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Bladder capacity should be noted. Capacity decreases in association with: Large pelvic masses In urinary and pelvic inflammatory disease Prostatic hypertrophy In patients receiving radiation therapy In advanced stages of tumor infiltration After recent surgery Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Postvoid residual volume calculation Patient asked to empty bladder to document presence and calculate volume of residual urine Longitudinal, AP, and transverse measurements are repeated and compared to another bladder volume calculation Determining amount of residual urine in cases of suspected bladder outlet obstruction improves treatment for patients Residual volume increases with: Age, atonic bladders, bladder neck obstruction, long-term cystitis, and advanced invasion by cancer Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques 3D and 4D Sonography: New dimension benefits imaging of lower urinary tract 3D has some advantages over 2D imaging Entire volume of data is stored allowing for manipulation of data set and reconstruction of images in all three scan planes after patient has left exam room Rendered image of interior bladder wall can provide a virtual sonographic cystoscopy examination 3D volume measurements can be obtained using virtual organ computer-aided analysis (VOCAL) which also creates 3D model of organs Copyright © 2018 Wolters Kluwer All Rights Reserved Physiology Scanning Techniques Endoluminal sonography is imaging technique being investigated due to revolutionary transducer technology Initial studies sonography is limited by high- frequency transducer (20 MHz) which allows penetration of only a few centimeters Greater penetration is required for upper urinary tract Endoluminal transducer may be ideal for examining urethra, bladder, and pelvic ureters Researchers may find intraoperative techniques advantageous Copyright © 2018 Wolters Kluwer All Rights Reserved Transverse Plane of Normal Anatomy A. Reverberation artifact echoes are seen in near field of a urine-filled bladder and uterus is identified posterior to bladder. B. The urethral orifice can be identified exiting the trigone. Copyright © 2018 Wolters Kluwer All Rights Reserved Transverse Plane of Normal Anatomy C. The ureteral orifices are seen as small mucosal elevations (arrows) as they enter the bladder. The anterior wall of the bladder demonstrates the reverberation artifact. C Copyright © 2018 Wolters Kluwer All Rights Reserved Anatomy: Longitudinal Plane of Normal Anatomy D E D. On the left, near the midline, the left ureteral orifice is seen entering the trigone. E. The right ureteral orifice is seen entering the trigone. BL, urinary bladder, OV, ovary. Copyright © 2018 Wolters Kluwer All Rights Reserved Normal Male Anatomy Liver Liver Aorta A B A.When scanning in a longitudinal plane in suprapubic region, the relationship between the urinary bladder (BL) and prostate (P) is visualized. B.On a transverse plane of male urinary bladder (BL), seminal vesicles can be identified bilaterally as hypoechoic structures inferior to hyperechoic posterior wall (arrows). Copyright © 2018 Wolters Kluwer All Rights Reserved Foley Catheter Longitudinal image of the urinary bladder; a Foley catheter (FC) can be identified within the bladder lumen. The catheter appears to be anechoic, with an echogenic exterior. Note the thickened bladder wall (arrows). Copyright © 2018 Wolters Kluwer All Rights Reserved  Normal Ureteral Jets—Transverse Planes A.Simultaneous jets of low-intensity echoes (arrows) are visualized entering urinary bladder (BL). B.Color Doppler demonstrates both right and left ureteral jets on transverse image on a male patient. Copyright © 2018 Wolters Kluwer All Rights Reserved  Three Dimensional Imaging Multiplanar reconstruction of the bladder demonstrates a small bladder tumor (arrow) seen simultaneously in sagittal, transverse, and coronal planes in addition to a rendered image of the bladder lining. The intersecting lines on each image represent the same anatomic location in all three planes. Copyright © 2018 Wolters Kluwer All Rights Reserved Quiz What phenomenon is seen with bursts of echoes entering the bladder from the trigone region? A. Urolithiasis B. Catheter shelf C. Ureteral jet D. Residual reflux Copyright © 2018 Wolters Kluwer All Rights Reserved Quiz What urinary bladder wall measurement indicates the need to further interrogate the bladder for a pathologic process? A. >3 mm B. >4 mm C. >5 mm D. >6 mm Copyright © 2018 Wolters Kluwer All Rights Reserved Abnormalities of the Lower Urinary Tract Duplication Three types of urinary bladder duplication: 1. Peritoneal fold: may be complete or incomplete 2. Septum: divides bladder either sagittally or coronally 3. Transverse muscle band: divides bladder into two unequal cavities Complete duplication of urinary bladder is rare Complications may arise from variations of this anomaly Unilateral reflux, obstruction, or infection may occur secondary to stenosis or atresia of urethra Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Duplication Duplication of ureters results when embryonic ureteric bud branches prematurely and leads to partial division and separation of related blastema Incomplete duplication includes bifurcation of ureter at or near renal pelvis that unites at a variable distance between kidney and bladder and enters bladder as a single ureter in normal bladder trigone Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Duplication Complete duplication when there are two separate renal collecting systems and two separate ureters Ureter from lower renal pelvis migrates and enters bladder in normal ureteral orifice in bladder trigone Ureter from upper pole of kidney inserts into bladder caudad to ureter from lower pole. Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Duplication In females: more caudad ureter may drain ectopically into trigone, perineum, uterus, vagina, or urethra In males: distal insertion can occur in trigone, urethra, or seminal vesicles Duplications may be unilateral or bilateral and are more common in females than in males Accessory or duplicate urethra is an uncommon malformation that occurs almost exclusively in males True duplication is associated with duplication of bladder and usually of genitalia Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Bladder Agenesis An absent bladder is a rare anomaly Most infants with bladder agenesis are stillborn Virtually all surviving infants are female During obstetric scan, it is important to allow adequate time for fetal bladder to fill and empty Renal agenesis is a lethal anomaly Fetal bladder is not identified during the obstetric scan Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Diverticula Bladder diverticula are pouch-like eversions of bladder wall Diverticula are produced by mucosal herniation through defects in muscle wall arising as congenital defects or acquired lesions Usually associated with diseases resulting in: Bladder outlet obstruction or Neurogenic conditions resulting in abnormalities in bladder function with chronically raised intravesical pressure Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Diverticula One frequent form is paraurethral (Hutch’s) diverticulum which forms because ureter is inserted at an inherently weak point in bladder wall Bladder diverticula are demonstrated sonographically as urine-filled outpouchings Careful scanning may show narrow communication between diverticulum and bladder which leads to diagnosis Intradiverticular tumors or stones may also be identified Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Diverticula Since diverticula may not empty and occasionally actually increase in size with voiding, postvoiding scans can demonstrate urine-filled diverticula Very large diverticula may be mistaken for: Bladder itself Duplication of bladder or Seminal vesicle or ovarian cysts Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Diverticula Color Doppler provides: Cost-benefit Rapid Noninvasive examination for differentiating bladder diverticula from other cystic masses and fluid collections by evaluating ureteral jets With color Doppler, diverticulum is demonstrated as a jet with alternating bidirectional flow between bladder and anechoic cystic diverticulum Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Diverticula Spontaneous rupture of bladder diverticulum is rare Without immediate diagnosis, condition may be mistaken for acute renal failure Misdiagnosis and mistreatment can be fatal Transabdominal sonography after injection of saline and air demonstrates: Extravasation Identifies injury site Is more specific than CT or radiographic cystography Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Diverticula Transperineal and transvaginal scanning is very effective in identifying urethral diverticula in women Normal urethra can be routinely identified on transvaginal or transperineal scans as a hypoechoic linear structure exiting from base of bladder and traveling inferior to symphysis pubis Hypoechoic to anechoic appearance of urethral wall muscles is due to their parallel orientation to ultrasound beam using these techniques Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Diverticula Anisotropy is an artifact encountered when sound beam is incident on a structure such as fibrillar, tendon, or ligament Variable echogenicity depending on relative orientation of transducer and structure being scanned is called anisotropy Whenever scanning urethra, determine resulting image is not confused with anechoic urine in urethra Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Diverticula Urethral diverticula appear as simple or complex collections of fluid intimately related to urethra Diverticular may involve both lateral aspects of urethra or wrap around urethra Can contain stones or cancer May be differentiated from periurethral abscesses with use of power Doppler Abscess is not vascular, but there is hypervascularity around abscess Copyright © 2018 Wolters Kluwer All Rights Reserved  Bladder Diverticulum A.Transverse image of bladder (BL) demonstrates two cystic areas posterior to the bladder (D). B.A slight rotation of the transducer reveals a connection between the cystic areas (D) and bladder consistent with bladder diverticula. Note debris within the diverticula that could indicate infection. C.Longitudinal image of the urinary bladder (BL) shows a large diverticulum (D). Note the connection between the bladder and the diverticulum (arrow). Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Posterior Urethral Valves The most common of bladder outlet obstructions results from the development of abnormal valves in the posterior urethra. The prostatic urethra is markedly dilated because of an obstruction at or just below the verumontanum (an elevation on the floor of the prostatic portion of the urethra where the seminal ducts enter). Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Posterior Urethral Valves Posterior urethral valve usually consists of a mucosal flap originating from verumontanum Posterior urethral valve syndrome is most common cause of urinary obstruction in male infants Almost 75% are discovered during first year of life May present in older children but rarely occur in adults Approximately 40% of patients have associated vesicoureteral reflux which is usually due to a periureteral diverticulum Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Posterior Urethral Valves Sonographic recognition of dilated and elongated prostatic urethra helps differentiate posterior urethral valves from neurogenic bladder dysfunction With posterior urethral valves, bladder wall appears thickened Hydroureters with dilation of upper urinary tract may be seen Other rare causes of bladder outlet obstruction include: Agenesis of urethra Congenital urethral strictures Urethral tumors Anterior urethral valves Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Posterior Urethral Valves Thickening of the bladder wall can also occur with cystitis In males: Anterior urethral obstruction is uncommon but may be secondary to strictures, diverticula, or urethral duplication. In females: Urethral obstruction in females is rare but may be seen in cloacal or female intersex anomalies Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Ureterocele Ureterocele is a cyst-like enlargement of lower end of the ureter Problems arise because: 1. Ureteral opening in wall of sac is stenotic and therefore hydroureter, hydronephrosis, and infection proximal to ureterocele are common 2. Ureterocele sac itself may obstruct bladder outlet or even prolapse through urethra Ectopic ureterocele is formed when ectopic ureter is obstructed in area where it enters bladder Causes its anterior wall to balloon into bladder Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Ureterocele Sonographic diagnosis of ectopic ureters and ectopic ureteroceles must include complete scanning of kidneys Duplex kidney may demonstrate two ureters arising from within Frequently they are difficult to distinguish Ectopic ureter may be massively dilated and tortuous in distal portion and mildly dilated proximally Many variations are reported Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Ureterocele Extremely large ureters sometimes mimic multiseptate, cystic abdominal masses Ectopic ureteroceles are dynamic structures that change shape and size according to intravesical pressure Occasionally, a dilated ectopic ureter may indent lower vesical bladder wall simulating an ectopic ureterocele on sonography Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Ureterocele Simple ureteroceles are easy to see with sonography In adults—ureteroceles are usually incidental findings located at expected location of distal ureteral orifice Sonographically, ureteroceles appear as round or oval, thin-walled cystic structure on posterior wall of a distended urinary bladder Real-time scanning shows these cystic areas as flexible in size as they fill and empty Color Doppler of ureteral jets verifies diagnosis Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Ureterocele Pathologic processes such as stones, tumors, or recent manipulation can cause pseudoureteroceles New transducer technology makes visualization possible of pseudoureteroceles which appear thicker walled Copyright © 2018 Wolters Kluwer All Rights Reserved Ureterocele A B A.Longitudinal image demonstrates a dilated ureter containing two echogenic calculi (arrows) and a thin- walled ureterocele (U) in bladder lumen (BL). B. Transverse urinary bladder images shows a small thin-walled mass (arrow) projecting into the bladder lumen. C C.Color Doppler demonstrates presence of ureteral jet confirming diagnosis of a small left ureterocele. Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Urachal Variants In the fetus, bladder is located at umbilicus and communicates with allantoic canal, extension of cloacae/urogenital sinus, into the umbilical cord Urachus is an embryonic tract formed as bladder begins its descent into true pelvis As this occurs, vertex of bladder elongates, forming a fibromuscular appendage approximately 5 cm long surrounding allantoic canal This tract is normally obliterated by time of birth If urachus fails to close, it creates an open channel between bladder and umbilicus Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Urachal Variants There are four types of urachal anomalies: 1. A patent urachus or fistula (completely patent lumen) occurs in 50% of cases Urachus fails to close prior to birth and is usually associated with urethral obstruction Urine may drain constantly from umbilicus Serves as a protective mechanism to avoid an obstruction of urinary bladder that may prevent normal fetal growth Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Urachal Variants 2. In 30% of cases, a urachal cyst develops when both ends of urachus close off, trapping a small amount of urine in the canal Clinically, patient presents with a palpable mass, possible fever, and dysuria Sonographically, a cystic structure is seen with possible internal echoes near midline between bladder and umbilicus Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Urachal Variants 3. A urachal sinus occurs in 15% of cases when urachus closes at bladder but not umbilicus 4. Urachal diverticulum occurs in 5% of cases when urachus closes at umbilicus and remains patent at bladder Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Urachal Variants Urachal variants are easily identified on sonography by their characteristic location adjacent to bladder dome Sonographically, an anechoic mass or a diverticular outpouching between bladder dome and umbilicus is identified Complications of a persistent urachal sinus include infection whereas complications of a urachal cyst include adenocarcinoma, calculi formation, or both When detected, urachal variants are easily reexamined due to easily assessable abdominal wall location Copyright © 2018 Wolters Kluwer All Rights Reserved  Abnormalities of the Lower Urinary Tract Urachal Variants A urachal remnant near bladder dome can form from neoplasms Mucinous adenocarcinoma is a leading precursor, and remnant occurs most commonly in men aged 50 to 60 years Stones may form in adenocarcinomas Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Abnormalities Abnormality Sonographic Appearance Diverticula Round, well-defined, thin-walled, fluid-filled masses with acoustic enhancement; variable in size. Color Doppler demonstrates bidirectional flow between bladder and cystic diverticulum. Posterior Dilated, elongated prostatic urethra (peculiar to urethral males); subsequently, thickened bladder wall, valve hydroureters, or dilated upper urinary tract may develop. Exstrophy Eversion through anterior abdominal wall; other findings include hydronephrosis caused by ureterovesical obstruction. Bladder Secondary abnormalities include vesicoureteral neck reflux, vesical diverticula, and large-capacity contracture bladder. Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Abnormalities Abnormality Sonographic Appearance Ectopic More common for ureter to arise from the upper ureter moiety of a duplex kidney; 10% to 20% arise from a solitary renal pelvis; may be massively dilated; may mimic multiseptate, cystic abdominal masses. Ectopic Anechoic, cyst-like, thin-walled mass of variable ureterocele size and shape projecting into the bladder (sometimes described as a cyst within a cyst). Persistent Anechoic mass or diverticular outpouching urachus between dome of the bladder and the umbilicus; cyst formation occurs if the ends seal off; adenocarcinoma or calculi may occur in a urachal cyst. Copyright © 2018 Wolters Kluwer All Rights Reserved Quiz Which pathology is demonstrated sonographically as an urine-filled outpouching? A. Posterior urethral valve B. Bladder agenesis in surviving female C. Duplication of ureters D. Bladder diverticula Copyright © 2018 Wolters Kluwer All Rights Reserved Quiz Which artifact creates variable echogenicity and is dependent on the relative orientation of the transducer and structure being scanned? A. Anisotropy B. Reverberation C. Comet tail D. Refraction Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Cystitis Urinary tract infections (UTIs) are extremely common Second, only in prevalence to respiratory infections. UTI is a frequent cause of hospitalization in United States and is responsible for significant morbidity and mortality Six million Americans are infected annually Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Cystitis Inflammation of bladder always suggests predisposing risk factors which include:  Urethral  Common rectal or vaginal obstruction fistulas  Catheterization  Surgical instrumentation  Bladder calculi  Bladder neoplasm  Trauma  Debilitating illness  Pregnancy  Sexual intercourse  Renal disease  Obstructive conditions  Radiation therapy  Diabetes  Poor hygiene Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Cystitis Most common cause of all urinary tract infections is gram-negative intestinal bacteria Escherichia coli Approximately 85% of all urinary tract infections are caused by E. coli. More common in females owing to short female urethra and proximity of urethral opening and vagina to anal area Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Cystitis Usually presents as thickened bladder mucosa with hypoechoic or cystic structures along the wall. Pathology Box on next slide lists: Types of cystitis Most common etiology Distinctive sonographic appearance of each type based on histopathology Diagnosis of the etiology requires correlation of sonographic appearance with patient’s Clinical signs Symptoms Medical history Copyright © 2018 Wolters Kluwer All Rights Reserved Cystitis Type Common Etiology Sonographic Manifestations Bullous Infection Focal bladder wall thickening in early, acute stages; small, contracted bladder in later, chronic stages. Candida Hematogenous, Mild thickening of bladder wall; albicans lymphatic, or direct discrete, dense, fluid–fluid-debris inoculation from anus interface shifts with changing position. Catheter Irritation to bladder Smooth, thickened, hypoechoic induced mucosa mucosa in early stages; redundant and polypoid in later stages. Cystic Nonspecific Confined to trigone; thickened, inflammatory; irregular mucosa with cyst-like associated with chronic elevations; associated intravesical cystitis or chronic mass. catheterization Copyright © 2018 Wolters Kluwer All Rights Reserved Cystitis Type Common Etiology Sonographic Manifestations Emphysema- Escherichia coli Echogenic, “dirty” shadowing tous produced by gas collection within bladder wall. Encrusted Urinary salts Focal bladder wall thickening in precipitate on early, acute stages; small, bladder surface contracted bladder in later, chronic stages. Glandularis Pelvic lipomatosis; Pronounced at ureterovesical chronic infection junction. Diffuse mucosal thickening. May have echogenic fat surrounding bladder. Hemorrhagic Prolonged Intraluminal, echogenic debris cyclophosphamide caused by blood clots or wall therapy thickening; focal calcification possible. Copyright © 2018 Wolters Kluwer All Rights Reserved Cystitis Type Common Etiology Sonographic Manifestations Purulent Neurogenic Pus-urine fluid level. dysfunction and urine stasis Radiation Radiation therapy Ulceration, bladder wall induced sloughing, mucosal irregularity, and fistula formation in later stages. Schistoso- Schistosoma Polypoid bladder wall thickening; miasis haematobium bladder wall calcifications with discrete shadowing; fibrosis and small, contracted bladder in later, chronic stages; vesicoureteral Copyright © 2018 Wolters Kluwer All Rights Reserved Cystitis A B A. Endovaginal image of urinary bladder shows a thickened irregular bladder wall (arrows) consistent with chronic cystitis. B. Longitudinal image of empty urinary bladder with Foley catheter in place (FC). The bladder wall is extremely thickened (between calipers) and collapsed around Foley catheter. Copyright © 2018 Wolters Kluwer All Rights Reserved Cystitis C D C. Transverse image of urinary bladder in a patient with hemorrhagic cystitis. A blood clot (arrows) is seen adhering to thickened bladder wall. D. CT pelvis scan in a patient with emphysematous cystitis shows air within the bladder wall (BL). Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Calculi Bladder calculi are usually single and may be asymptomatic May cause inflammatory changes or acute bladder neck obstruction Bladder neck obstruction by a calculus obstructs flow of urine from body Predisposing factors to stone formation include: Increased concentration of salts in urine Infection of urinary tract Urinary tract obstruction or stasis Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Calculi Calculi usually appear as echogenic foci in bladder, have an associated acoustic shadow, and shift to dependent bladder portion with patient position changes Anterior fluid-filled bladder provides an excellent acoustic window for identification of bladder calculi Stones do not have to be calcified to be identified sonographically Sonography can distinguish uric acid stones which have acoustic shadow and shift position from a bladder tumor which appears as fixed mass without an acoustic shadow Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Calculi Intradiverticular calculi can also be identified sonographically In a patient with diverticula, infection and stone formation are common findings due to the stasis of residual urine remaining postvoid Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Calculi A B A.Longitudinal urinary bladder image shows a well- defined, hyperechoic density with an acoustic shadow along the posterior bladder wall consistent with a bladder calculus (arrow). B.Transverse urinary bladder image shows multiple bladder calculi (large arrows) and a thickened irregular bladder wall (small arrows). Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Calculi C C. Longitudinal urinary bladder image shows a small hyperechoic bladder calculus (small arrow) along the posterior bladder wall. The bladder calculus moved with a change in patient position. Reverberation is seen along the anterior bladder wall (R). Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Reflux Normally, the vesicoureteral junction allows urine to enter bladder but prevents it from being regurgitated back into ureter, particularly at time of voiding This protects kidney from high pressure in bladder and from contamination by infected vesical urine When valve is incompetent, chance for secondary development of infection in upper urinary tract is significant Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Reflux Reflux may occur as a result of an abnormality of trigone and secondary to anomalies such as ectopia, posterior urethral valves, paraureteric cyst, prune belly syndrome, and neurogenic bladder. Vesicoureteral reflux occurs in two distinct groups: 1. Neonatal reflux which is seen more commonly in males 2. Reflux in older children which is more common in females Hydronephrosis, either unilateral or bilateral, can be seen on a prenatal sonography examination Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Reflux There is a high incidence of contralateral renal abnormalities, including ureteropelvic junction obstruction and duplex kidney High-pressure reflux (with or without associated UTI) may be a major cause of chronic renal failure with marked scarring and atrophic changes in the kidneys Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Reflux Sonography examination is valuable in management of children with reflux: It is less expensive Employs sound and not ionizing radiation Can identify specific abnormalities In transverse plane—meticulously scan in area where ureters enter bladder Ureter often dilates with urine as reflux is in progress This may be visualized with real-time sonography Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Distal Ureteral Obstruction Ureterovesical junction obstruction describes obstruction at junction of distal ureter where it enters the bladder A voiding cystourethrogram (VCUG) may be necessary to differentiate a ureterovesical junction obstruction from nonobstructive causes such as reflux Causes of distal ureteral obstruction may be congenital or acquired Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Distal Ureteral Obstruction Congenital Causes include: Acquired causes include:  Primary megaureter  Ureteral reimplantation  Primary megaureter with procedures coexisting reflux  Infection  Primary megaureter with  Stricture following coexisting bladder passage of stones saccule  Simple ureterocele  Ectopic ureter  Ectopic ureterocele Sonographic findings include:  Megaureter  Hydronephrosis  Ectopic ureter with or without ectopic ureterocele Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Neurogenic Bladder A patient with a neurogenic bladder has lost voluntary control of voiding due to a disturbance in neural pathways Depending on nerves involved and nature of damage, bladder becomes: Overactive (spastic or hyperreflexive) or Underactive (flaccid or hypotonic) Myelodysplasia—neural tube defect—defective development of part of spinal cord Most common cause of neurogenic bladder in infants and children Neurogenic bladder is common in paraplegic patients Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Neurogenic Bladder—Other causes include: 1. Neurologic diseases (multiple sclerosis, syringomyelia, Parkinson disease) 2. Congenital anomalies (partial or total absence of the sacrum or meningomyelocele) 3. Systemic diseases with neurologic complications (diabetes mellitus, pernicious anemia) 4. Infection (herpes zoster, poliomyelitis, spinal cord abscess) 5. Trauma (vertebral fractures, operative trauma, disk herniation) 6. Brain and spinal neoplasm 7. Central nervous system vascular disease 8. Heavy metal poisoning Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Neurogenic Bladder Individuals with overactive bladder have little to no control over voiding functions Bladders release urine spontaneously and frequently, although not completely Bladders become diminished because they are seldom filled to capacity Because their bladders tend to retain small quantities of urine, risk of UTI is significantly increased Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Neurogenic Bladder Neurogenic underactive bladders have opposite characteristics Because there is damage to the neural system and brain is not informed that bladder is full, bladder continues to fill and may expand beyond size and capacity of a normal bladder At a certain point, pressure of urine in bladder will overcome sphincter muscles’ ability to retain urine and urine will leak out Like overactive bladder, an underactive bladder fails to empty completely and retains a small amount of residual urine Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Neurogenic Bladder Many patients have a trabeculated bladder and spasm of external sphincter causing relative obstruction and narrowing of urethra as it courses through urogenital diaphragm Patient may find it extremely difficult or impossible to void Because of obstruction, pressure in bladder remains constantly high—which may result in detrusor hypertrophy, formation of saccules and diverticula, and vesicoureteral reflux Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Neurogenic Bladder Since urine is chronically infected in such patients, result may include: Chronic reflux pyelonephritis Formation of struvite stones Bladder debris Patients with neurogenic bladder usually undergo serial excretory urography and voiding cystourethrograms Sonography is performed to aid in diagnosis of:  Trabeculated bladder  Ureterectasis  Vesicoureteral reflux  Hydronephrosis  Bladder calculi Copyright © 2018 Wolters Kluwer All Rights Reserved Neurogenic Bladder A B A.Longitudinal images show presence of bladder saccules (arrows)—a sign that bladder outlet obstruction has begun to have adverse effects on urinary tract. B.Postvoid image shows a large postvoid residual within C bladder. Bladder saccules (arrows) are seen along C.Longitudinal images of lateral wall. both kidneys show bilateral hydronephrosis. Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Bladder Wall Abnormalities Thickening of bladder wall is one of the most frequent sonographically observed abnormalities of the bladder Commonly due to outlet obstruction Other causes include:  Neurogenic bladder  Cystitis  Edema from adjacent inflammatory processes  Radiation  Primary or secondary neoplasms Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Bladder Wall Abnormalities Patients with inflammatory bladder pathology may have signs and symptoms similar to patients with urinary bladder or kidney neoplasm Certain pathologic conditions are manifested with extrinsic bladder compression, invasion of urinary bladder, or both Endometriosis can present as intravesical lesion by either direct extension or implantation Regional enteritis (Crohn disease) reported as loop of small bowel with thick walls and narrowed lumen adhering to bladder dome Focal or diffuse bladder wall thickening can occur with neurofibromatosis Copyright © 2018 Wolters Kluwer All Rights Reserved Pathology in the Lower Urinary Tract Bladder Wall Abnormalities In arteriovenous malformation, there is an abnormal connection between arterial and venous vessels Higher pressure in arterial system causes blood to be routed directly from artery into vein, which increases blood flow through veins A natural response for vein under increased blood volume is to dilate Copyright © 2018 Wolters Kluwer All Rights Reserved Causes of Bladder Wall Thickening Focal Diffuse Neoplasm Transitional cell carcinoma Transitional cell carcinoma Squamous cell carcinoma Squamous cell carcinoma Adenocarcinoma Adenocarcinoma Lymphoma Fistula Copyright © 2018 Wolters Kluwer All Rights Reserved Causes of Bladder Wall Thickening Focal Diffuse Infectious/Inflammatory Tuberculosis (acute) Cystitis Schistosomiasis (acute); flukes living Tuberculosis in the pulmonary venous system and (chronic) its tributaries or within the veins draining the bladder; serious destruction to surrounding tissue; “swimmers itch” Cystitis Schistosomiasis (chronic) Cystitis cystica Cystitis glandularis Fistula Copyright © 2018 Wolters Kluwer All Rights Reserved Causes of Bladder Wall Thickening Focal Diffuse Medical Diseases Endometriosis Interstitial cystitis Amyloidosis Amyloidosis Trauma Neurogenic Bladder Hematoma Detrusor hyperreflexia Ruptured bladder Bladder Outlet Obstruction with Muscular Dystrophy Copyright © 2018 Wolters Kluwer All Rights Reserved Quiz Urinary tract infections are second in prevalence to which pathology? A. Cholelithiasis B. Pancreatitis C. Hepatitis D. Respiratory infections Copyright © 2018 Wolters Kluwer All Rights Reserved Quiz Which pathology of the lower urinary tract is one of the most frequent sonographically observed abnormalities? A. Bladder wall thickening B. Neurogenic bladder C. Reflux D. Urolithiasis Copyright © 2018 Wolters Kluwer All Rights Reserved Trauma Rupture Bladder rupture follows severe blunt lower abdominal or pelvic trauma or penetrating abdominal or perineal injury If bladder was full at time of blunt injury, rupture is more likely to occur, spilling urine into peritoneum Pelvic crush injuries cause bladder rupture in 1% to 15% of cases 80% (four-fifths) bladder rupture cases are extraperitoneal Copyright © 2018 Wolters Kluwer All Rights Reserved Trauma Rupture Urinoma may result from temporary sealing of a small tear Sonographic appearance of urinoma is anechoic mass with enhanced through-transmission Mass may have irregular borders and contain septa Mass may compress surrounding tissue Best diagnostic procedure for visualizing bladder rupture is cystography Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Rupture A B A.Transverse pelvis image in a man who experienced recent blunt pelvic trauma. Complex mass (arrows) is seen to right of urinary bladder (BL). Mass is consistent with a hematoma. No color flow is seen within the mass. B.Longitudinal image to right of bladder shows complex hematoma (arrows). Copyright © 2018 Wolters Kluwer All Rights Reserved Trauma Blood Clots Blood clots, either from a pathologic process or from trauma, may adhere to bladder wall Gives sonographic appearance similar to a tumor Clots appear as an irregularity along mucosal surface. Most clots are mobile and will move freely with changes in patient’s position Clots will not demonstrate the presence of vascularity with color Doppler Copyright © 2018 Wolters Kluwer All Rights Reserved Blood Clot A. Longitudinal bladder image —irregular, echogenic mass (arrows) along posterior abdominal wall— diagnosed as a blood clot within the bladder. B. Transverse bladder image —large echogenic mass A (arrows) along posterior bladder wall—diagnosed as a blood clot developed after a renal biopsy. B Copyright © 2018 Wolters Kluwer All Rights Reserved Blood Clot C C. Longitudinal bladder image—large irregular, echogenic mass (arrows) along posterior abdominal wall—mass diagnosed as blood clot within the bladder. Copyright © 2018 Wolters Kluwer All Rights Reserved Trauma Bladder Flap Hematoma During a cesarean section, surgeon incises vesicouterine reflection of peritoneum to obtain access to lower uterine segment Creates potential space between bladder and uterus commonly known as bladder flap If hemostasis is not obtained after closure of uterine incision, a hematoma forms between lower uterine segment and urinary bladder (bladder flap) or anywhere surgical scalpel made an incision (abdominal wall, muscle) Copyright © 2018 Wolters Kluwer All Rights Reserved Trauma Bladder Flap Hematoma Patient with a hematoma can present with: Fever Mass Dropping hematocrit An infected hematoma can manifest with same symptoms but patient can additionally have leukocytosis and more pain Fever can be caused by infected hematoma alone or by postsurgical complications such as:  Endometritis Septic thrombophlebitis  Abscess  Hematoma  Wound infection Copyright © 2018 Wolters Kluwer All Rights Reserved Trauma Bladder Flap Hematoma Incidence of bladder flap hematoma is unknown Sonographic appearances described in literature vary significantly and include a mass as large as 15 × 12 × 9 cm (length × width × height) Majority of bladder flap hematomas are complex masses with poorly defined borders that are primarily anechoic, with internal septations or debris Because it is not possible to differentiate sonographically between a hematoma, an infected hematoma, and an abscess, patient’s clinical presentation is important Copyright © 2018 Wolters Kluwer All Rights Reserved Trauma Bladder Flap Hematoma A symptomatic patient with a clinical history of: Leukocytosis suggests an abscess Dropping hematocrit suggests a hematoma Dropping hematocrit with leukocytosis suggests infected hematoma Copyright © 2018 Wolters Kluwer All Rights Reserved Trauma Bladder Flap Hematoma If a suspected hematoma is near incisional site of abdominal wall, a high-frequency (5 to 10 MHz) linear array transducer and a standoff pad may be required to examine superficial area If incisional site has not healed, sterile gel and a transducer cover must be used to reduce risk of contamination Area may be more difficult to examine because of incisional pain and tenderness Copyright © 2018 Wolters Kluwer All Rights Reserved Trauma Bladder Flap Hematoma To distinguish between a superficial wound and a subfascial hematoma, rectus muscle must be identified Superficial hematomas are located anterior to rectus muscle and subfascial hematomas are located posterior to rectus muscle The typical location for a subfascial hematoma is in prevesicular space, ventral to bladder Based on sonographic appearance, a superficial hematoma or a subfascial hematoma may appear same as abscess or an infected hematoma, making clinical correlation extremely important Copyright © 2018 Wolters Kluwer All Rights Reserved Quiz What is the best diagnostic procedure for visualizing a bladder rupture? A. CT B. MRI C. Cystography D. Sonography Copyright © 2018 Wolters Kluwer All Rights Reserved Quiz Which clinical presentation suggests an infected hematoma or postsurgical complication to rule out a bladder flap hematoma on a symptomatic patient where it is not possible to differentiate sonography appearance between a hematoma, an infected hematoma, or an abscess? A. Fever B. Dropping hematocrit C. Dropping leukocytes D. Increased variance of hemoglobin Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Neoplasms Bladder tumors are frequently found in urogenital imaging in patients having renal sonography for painless hematuria Bladder tumors are usually epithelial or uroepithelial in origin and are one of most common tumors of the genitourinary tract While painless hematuria is most common symptom, other symptoms may include dysuria, urinary frequency, or urgency An infiltrating tumor disrupts uniformity of normal 3 to 5 mm bladder wall thickness Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Neoplasms Hydronephrosis often occurs due to obstructed outflow of urine Blood clot, benign prostatic hypertrophy, cystitis, fungal balls, stones, and bladder trabeculae can mimic bladder tumors For initial screening of suspected bladder tumor, sonography is excellent noninvasive, cost-effective, and nonionizing imaging modality Cystoscopy involves inserting a cystoscope through the urethra into the bladder Cystoscopy with biopsy is considered most accurate method for detecting and evaluating bladder tumors but it is invasive and requires anesthesia Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Neoplasms Tumors located in bladder neck or dome are difficult to detect with sonography Ability of sonography to detect presence or absence of bladder tumors has varied: 33% for tumors smaller than 0.5 cm in diameter 83% for tumors 1 to 2 cm 95% for tumors larger than 2 cm Apart from the size and location of tumor, degree of bladder distention or obesity may affect accuracy of tumor detection Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Neoplasms Endovaginal longitudinal scanning has proven effective in diagnosis of tumors located in any part of urinary bladder Endovaginal approach provides good image quality, allowing tumor to be studied in detail through anterior wall, neck, and apex of urinary bladder Bladder tumors situated on sidewall are harder to stage by endovaginal sonography Following diagnosis of carcinoma of bladder, sonography can also be helpful in staging tumors Evidence indicates that stage of tumor profoundly influences curability and survival time Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Neoplasms Tumor’s response to chemotherapy is primary determinant of whether to continue therapy Sonography is useful adjunct to cystoscopy when serial scans of bladder tumors are performed When sonography and cystoscopy are used together, bladder tumor staging is more accurate than when either study is used alone CT is imaging modality of choice for identifying contiguous extension of bladder neoplasms and has reduced number of overstaging and understaging Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Neoplasms Benign Neoplasms Papilloma, a benign tumor, is a forerunner of transitional cell carcinoma Sonographically, papillomas are usually 0.5 to 2 cm in size and have same appearance as transitional cell carcinoma The most common location is along lateral urinary bladder wall Second most common location is the trigone Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Neoplasms Malignant Neoplasms National Cancer Institute: each year over 70,000 new cases of bladder cancer are diagnosed and over 14,000 patients will die from disease Bladder carcinoma is fourth most common type of cancer in men and eighth most common in women Men, Caucasians, and smokers have up to three times risk of bladder cancer than general population When diagnosed and treated in a localized stage, bladder cancer is very treatable, with a 5-year cancer-specific survival rate approaching 95% Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Neoplasms Malignant Neoplasms 90% are transitional cell carcinoma (TCC)—cancer begins in cells that normally make up inner lining of bladder Smoking, analgesic abuse, and industrial carcinogen exposure predispose patients 5% are squamous cell carcinomas—most aggressive of malignant tumors Associated with chronic inflammatory conditions, neurogenic bladder, stones, and patients having bladder schistosomiasis 2% are adenocarcinomas which are associated with urachal remnants and bladder exstrophy Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Neoplasms Malignant Neoplasms Sonographically, transitional cell carcinoma tumors are visualized as: Irregular echogenic mass Either polypoid or sessile Projects into bladder lumen Fixed to bladder wall May have associated acoustic shadowing Color Doppler shows detectable blood flow in malignant bladder tumor Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Neoplasms Malignant Neoplasms Malignant primary urinary bladder tumor should be suspected whenever there is focal thickening of bladder wall Sonographically, malignant masses present as echogenic structures protruding into the echo-free bladder lumen Infiltrating tumors disrupt the normal uniformity of bladder wall Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Tumors A. Transverse male pelvis image shows a focal irregular thickening of right lateral bladder wall (arrows) consistent with bladder carcinoma. The prostate (P) is posterior to urinary bladder (BL). B. Transverse male pelvis image shows a grossly enlarged prostate gland (P) indenting posterior bladder wall. An enlarged prostate gland can be mistaken for a bladder tumor. Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Tumors  C-D Longitudinal urinary bladder images demonstrate an irregular, echogenic mass projecting into the bladder lumen (M).  Note bladder wall thickening along the bladder wall (arrows).  Reverberation is seen along anterior bladder wall (R).  Color Doppler reveals flow within the mass helping to distinguish the bladder tumor from a blood clot. Copyright © 2018 Wolters Kluwer All Rights Reserved Bladder Neoplasms Metastatic Metastatic urinary bladder tumors occur most commonly by direct extension from cervix, uterus, prostate, and rectum, in that order Tumors may also develop from direct extension from upper urinary system directly, or by lymphatic or vascular system Prostatic cancer usually metastasizes to seminal vesicles and perivesical connective tissue Copyright © 2018 Wolters Kluwer All Rights Reserved Metastatic Invasion C Transrectal prostate image demonstrates a large tumor from prostate invading the urinary bladder. Metastatic tumors of the urinary bladder can occur as a result from direct extension of prostate cancer. Copyright © 2018 Wolters Kluwer All Rights Reserved Quiz What is the imaging modality of choice for identifying contiguous extension of bladder neoplasms and has reduced the number of overstaging and understaging errors? A. CT B. MRI C. PET D. Sonography Copyright © 2018 Wolters Kluwer All Rights Reserved Quiz Of all of the cancers diagnosed in women, what is the frequency of bladder cancer? A. Second most common B. Fourth most common C. Sixth most common D. Eighth most common Copyright © 2018 Wolters Kluwer All Rights Reserved Chapter 11 Outline: The Lower Urinary System I. Anatomy and IV. Pathology of the Lower Urinary Organogenesis Tract A. Urinary Bladder A. Cystitis 1. Trigone B. Calculi B. Ureters C. Reflux C. Urethra D. Distal Ureteral II. Physiology Obstruction A. Patient Preparation E. Neurogenic Bladder B. Scanning Techniques F. Bladder Wall III. Abnormalities of the Lower Abnormalities Urinary Tract V. Trauma A. Duplication A. Rupture B. Bladder Agenesis B. Blood Clots C. Diverticula C. Bladder Flap D. Posterior Urethral Hematoma Valves VI. Bladder Neoplasms E. Exstrophy A. Benign Neoplasms F. Contracture of the B. Malignant Neoplasms Bladder Neck C. Metastatic G. Ectopic Ureter VII. Stress Incontinence H. Ureterocele I. Urachal Variants Copyright © 2018 Wolters Kluwer All Rights Reserved Stress Incontinence Most common micturition abnormality is stress incontinence 40% of postmenopausal women are affected by incontinence Condition is caused by: Genuine stress incontinence Detrusor instability Voiding difficulty (overflow) Fistulas Functional or congenital disorders It may be temporary condition due to urinary tract infections Copyright © 2018 Wolters Kluwer All Rights Reserved Stress Incontinence Stress incontinence is leakage of urine from bladder during acts that increase intra-abdominal and intravesicular pressure, such as: Valsalva maneuvers Coughing Straining Incontinence is receiving increased attention by both public and medical professionals Many women suffer stress incontinence and are too embarrassed to admit it, seek help, or are unaware of available treatments. Urogynecology surgical specialty field has emerged as demand has increased for more detailed understanding of normal female pelvic floor anatomy Copyright © 2018 Wolters Kluwer All Rights Reserved Stress Incontinence Sonography is being used to diagnose and treat incontinence. Sonographic evaluation of stress incontinence requires more detailed pelvic floor assessment Endovaginal, endorectal, transperineal, and transabdominal methods can all be used to directly observe bladder filling and emptying 3D sonography plays an important role in urogynecologic research Endovaginal sonography is sensitive and specific but cannot be used exclusively to determine urinary stress incontinence in females Copyright © 2018 Wolters Kluwer All Rights Reserved Stress Incontinence Pitfalls of using transperineal method include: Overdistended bladder Poor penetration An excessively small field of view Bowel gas Focal uterine contractions Bladder mistaken for cervix Fluid in vaginal vault mistaken for cervix Cervical cysts Pericervical veins Copyright © 2018 Wolters Kluwer All Rights Reserved Stress Incontinence Stress incontinence is caused by a poorly supported bladder neck Section between bladder and urethra Coughing or bearing down results in the bladder neck moving inferiorly, urethra opens, and urine is pushed out Depending on extent of findings, surgical repair can be an option A suburethral sling and an anterior repair can be performed and consist of placing a small piece of plastic around bladder neck to hold it in place, and at same time, lifting and stabilizing sagging bladder Copyright © 2018 Wolters Kluwer All Rights Reserved Quiz When sonographically evaluating stress incontinence, what is a pitfall of using the transperineal method? A. Penetration is too deep B. Bladder is overdistended C. Field of view is excessively large D. Fluid in the cervix is mistaken for vaginal vault Copyright © 2018 Wolters Kluwer All Rights Reserved