34 - Anomalies of the Genitourinary Tract

Authors: Macfarlane, Michael T.

Title: Urology, 4th Edition

Copyright 2006 Lippincott Williams & Wilkins

> Table of Contents > Part Two - Selected Topics > Chapter 34 - Anomalies of the Genitourinary Tract

Chapter 34

Anomalies of the Genitourinary Tract

Kidney Anomalies

Agenesis

Absence of renal tissue is probably related to an interruption or loss of ureteral bud development that prevents maturation of the metanephric blastema. The major renal vessels are always absent.

Unilateral

Incidence is 1 in 1,100, with a slight increased frequency on the left side and an autosomal dominant inheritance noted in recent studies. Absence of the ipsilateral hemitrigone is usually diagnostic; however, a normal trigone does not rule out renal agenesis. The diagnosis is made with renal scan and ultrasound. A high association with other congenital anomalies, such as absence of vas deferens in male patients and absence or hypoplasia of the tubes, ovaries, uterus, or vagina (Meyer-Rokitansky syndrome) in female patients on the affected side, is noted. Gastrointestinal anomalies, such as imperforate anus, also are found.

Bilateral

This rare condition is incompatible with life.

Potter's Syndrome

Absence of intrauterine urine production results in oligohydramnios; death is usually secondary to pulmonary hypoplasia. Characteristic Potter's facies is noted.

Anomalies of Rotation

Malrotation generally occurs around the vertical axis, with persistent anterior position of the renal pelvis being the most common type. It may be unilateral or bilateral and is often associated with ectopy or fusion. Bizarre urograms result.

P.239

Anomalies of Position and Fusion

Renal ectopy can be classified as simple (kidney on its normal side) or crossed ectopy (on the contralateral side) with or without fusion. Fusion is defined as the anatomic union of two or more kidneys.

Pelvic Kidneys

Pelvic kidney is the most recognizable ectopic kidney, with an incidence of 1 in 2,000, and usually occurs in male patients on the left side. Fifty percent of these will be pathologic with poor function, and 10% are solitary. Other coincident genitourinary anomalies, such as cryptorchidism or absence of the vagina, are common. These kidneys are difficult to identify on intravenous urogram (IVU) because of their poor function and position against the bony pelvis. Reflux is common. A voiding cystourethrogram (VCUG) can help make the diagnosis.

Thoracic Kidneys

Thoracic kidneys are extremely rare; most occur in male patients on the left side.

Crossed Renal Ectopia

These kidneys are more commonly fused than not fused and are usually on the right, with the crossed kidney lying inferiorly. A 2:1 male preponderance is noted. The ureteral orifices are located normally. The shape of the fused kidney can be quite unusual.

Horseshoe Kidney

Horseshoe kidney is the most common type of fusion, occurring in 1 in 400, with 90% fused at the lower poles. They are often associated with other urogenital anomalies and an increased incidence of renal pelvic tumors. One third of patients remain asymptomatic, whereas others may present with symptoms of hydronephrosis [ureteropelvic junction (UPJ) obstruction], infection, or stones. The renal axis is shifted on kidney, ureter, and bladder (KUB) film so that the lower poles are closer to the vertebral bodies. The ureters lie anterior to the renal pelvis and isthmus on IVU. Reflux and UPJ obstruction occur often. Ureteroneocystostomy to treat reflux may be necessary. Dividing the renal isthmus is usually not necessary.

Renal Hypoplasia

Hypoplasia refers to reduced renal mass (i.e., fewer than normal cells or nephrons) without histologic evidence of dysplasia.

P.240

Oligomeganephronia

Oligomeganephronia is a congenital renal disease occurring primarily in male infants (3:1), with progressive renal failure by age 12 to 15 years. The kidneys have fewer than normal nephrons (oligonephronia) but are hypertrophied (mega). Patients are treated medically with high fluid intake and correction of salt loss until eventually dialysis and transplantation are required.

Renal Dysplasia

Dysplasia is a form of abnormal renal morphogenesis characterized histologically by primitive ducts and cartilage. Varying degrees of hypoplasia are always present. Most hypodysplastic kidneys have ectopic ureteral orifices. The more ectopic the orifice, the greater the degree of dysplasia.

Renal Cystic Diseases

Many different classification schemes have been advanced. The major entities follow.

Autosomal Recessive Polycystic Kidney Disease

Autosomal recessive (infantile) polycystic kidney disease (ARPKD) is a rare anomaly with no sex predilection. Neither parent shows evidence of the disease, and siblings of either sex have a 1 in 4 chance of being affected. Ultrasound will show massively enlarged kidneys bilaterally, and IVU will show characteristic radial or medullary streaking of the nephrogram from cystic dilatation of the collecting tubules. Renal insufficiency occurs early. Infants with evidence of the disease at birth often die within the first 2 months. Patients will have some form of liver disease, ranging from periportal biliary ectasia to congenital hepatic fibrosis. A liver biopsy can establish the diagnosis. For those patients who survive infancy (50%), the course and progression of the disease are variable; however, cardiac, renal, and hepatic failure can be expected. ARPKD has no known cure.

Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant (adult) polycystic kidney disease (ADPKD) is the most common form of cystic kidney disease in humans and is responsible for approximately 10% of all cases of end-stage renal disease (ESRD). Approximately 500,000 Americans have been diagnosed. The trait has 100% penetrance, and 50% of an affected

P.241

individual's offspring also will be affected. This condition is characterized by diffuse bilateral progressive cystic degeneration of the kidneys, hypertension, and progressive renal failure. Most cases are identified between the ages of 30 and 50 years. Typical signs or symptoms include gross or microscopic hematuria, flank pain, gastrointestinal symptoms (colonic diverticula), renal colic (from clots or stones), and hypertension. Associated anomalies include hepatic cysts or fibrosis, berry aneurysms (10% to 40%), mitral valve prolapse, and colonic diverticulosis.

Treatment

Hypertension should be managed aggressively. Stones develop in 20% to 30% of patients with ADPKD and should be treated conservatively with urine alkalinization and extracorporeal shock wave lithotripsy (ESWL). Unnecessary instrumentation of the urinary tract should be avoided because of the high risk of infection in polycystic kidneys. Upper-tract infection is more successfully managed with lipid soluble antibiotics such as trimethoprim sulfamethoxazole (TMP-SMX) or fluoroquinolones. Renewed interest in surgical/laparoscopic cyst unroofing has been beneficial in relieving pain associated with the cysts. Renal failure can be managed with dialysis or renal transplantation.

Congenital Multicystic Kidney Disease

Congenital multicystic kidney disease is a common benign dysplastic malformation of the fetal kidney secondary to obstruction from ureteropelvic occlusion, ureteral atresia, or agenesis. It presents predominantly in male infants, on the left side, with a large, unilateral, multicystic, nonfunctioning renal abdominal mass. A 10% to 15% incidence of significant anomalies of the contralateral upper urinary tract is found. Elective surgical excision is indicated if the mass interferes with respiration or alimentation of the child or is associated with significant hypertension. Otherwise, attention is directed primarily toward identifying any abnormalities of the contralateral urinary tract.

Simple Cysts (Retention Cysts)

The most common cystic lesions of the kidney, simple cysts, may be solitary or multiple, unilateral or bilateral. They present clinically as an abdominal mass or more commonly as an incidental finding on ultrasound, IVU, or computed tomography (CT) scan. Differentiation among cystic neoplasms, lymphatic cysts, perirenal effusions, and renal abscesses must be made, in addition to polycystic disease, when they are multiple. A cystic renal cell carcinoma must be ruled out.

P.242

A simple cyst is characteristically unilocular, avascular, smooth walled, and filled with a clear fluid with low fat and protein content and a low lactic dehydrogenase with no malignant cells on cytology. Most complex cysts (Bosniak III or IV) on ultrasound or CT should undergo surgical exploration (see Chapter 15).

Medullary Sponge Kidney

Medullary sponge kidney is a congenital deformity of the renal medulla consisting of multiple, puddle-like dilatations of the collecting ducts in the papillae on IVU. These ectatic tubules are not true cysts but give a characteristic fan-shaped pyramidal blush on IVU that is diagnostic. The disease is bilateral in 75% of patients. Although its course and progression are generally benign, its clinical importance is its predisposition to calcium phosphate nephrolithiasis in the adult, presenting with renal colic and hematuria secondary to stone passage. Treatment consists of preventing infection and stone formation.

Tuberous Sclerosis (Bourneville's Disease)

Tuberous sclerosis is a familial autosomal dominant condition characterized by congenital tumors. Clinical features include the following:

• Facial nevi ( sebaceous adenoma )

• Recurrent convulsive seizures

• Mental retardation

• Multiple angiomyolipomas in up to 50%

• Occasionally, diffuse renal cystic disease that can result in chronic renal failure.

von Hippel Lindau Disease

von Hippel Lindau disease is an autosomal dominantly inherited syndrome manifested by retinal and cerebellar hemangioblastomas; cysts of the kidney, pancreas, and epididymis; pheochromocytomas; and renal cell carcinoma in 30% to 40% of patients. Renal cysts are often multiple and bilateral and appear to be precursors of malignant tumors. Yearly abdominal CT is recommended in these patients because of the high incidence of renal cell carcinomas. Shelling out these tumors rather than radical surgery is appropriate in view of their multiplicity.

Acquired Renal Cystic Disease

Acquired renal cystic disease is the appearance of bilateral multiple cysts in previously noncystic native kidneys of patients with ESRD. The risk of developing these cysts appears to be related to

P.243

uremic toxins. Their significance lies in their apparent premalignant nature. The incidence of renal cell carcinoma is three to six times greater in patients on dialysis. Complaints of flank pain or hematuria or both in an ESRD patient should be investigated for acquired renal cystic disease or renal cell carcinoma.

Anomalies of the Collecting System

Extrarenal Pelvis

Extrarenal pelvis predisposes to stasis, infection, and stone formation.

Bifid Pelvis

Bifid pelvis is a normal variant that occurs in 10% of the population.

Congenital Calyceal Diverticulum

Congenital calyceal diverticulum is a cystic cavity lying in the peripheral renal parenchyma connected to a calyx or the renal pelvis. Distention with urine can cause pain; however, infection and stone formation secondary to stasis are the most common complications. Diagnosis is made with IVU, retrograde pyelogram, or CT scan.

Hydrocalycosis

Hydrocalycosis is a rare cystic dilatation of a major calyx secondary to obstruction at the level of the infundibulum.

Congenital Megacalyces

Congenital megacalyces is a stable malformation of markedly enlarged calyceal cavities without evidence of obstruction. It occurs in male patients, in a 6:1 ratio, is highly associated with megaureter, and predisposes to infection and stones. The diagnosis is made with IVU, with a negative furosemide (Lasix) renal scan or Whitaker test. Preventing infection and stone formation with a high fluid intake is the goal of management.

Ureteral Anomalies

Ureteropelvic Junction Obstruction

Obstruction at the UPJ is a common congenital anomaly resulting in an obstruction to urine flow of varying degrees. Lesser degrees

P.244

of obstruction become symptomatic only with diuresis. UPJ obstruction occurs more commonly in male patients (2:1), with most cases diagnosed within the first year of life. Left-sided lesions predominate, and up to 40% are bilateral. Few cases are noted after puberty and into adulthood.

Etiologies

• Intrinsic lesion of the circular smooth muscle of the UPJ

• Extrinsic compression by an aberrant, accessory, or early-branching vessel to the lower pole

• Obstruction secondary to severe reflux, resulting in kinking of a tortuous ureter

Diagnosis

Today UPJ obstruction is diagnosed almost exclusively in the prenatal period because of the wide use of maternal ultrasonography. Renal ultrasound should be repeated postnatally after the first few weeks of life. Infants may present with an asymptomatic abdominal mass or urosepsis. Adults may have episodic flank pain, especially during diuresis. Doppler ultrasound measurement of the vascular resistive index (>0.70) can help identify significant obstruction in infants. An IVU will show a markedly hydronephrotic kidney with abrupt cutoff at the UPJ. A diuretic MAG3 or diethylenetriaminepentaacetate (DTPA) renogram is often helpful in equivocal cases. A VCUG is mandatory to rule out severe reflux as the cause of hydronephrosis. A dimethylsulfoxide (DMSA) renal scan may sometimes be helpful to determine the degree of renal function in the obstructed kidney. A Whitaker test can be used on occasion if a nephrostomy tube is in place.

Treatment

Pyeloplasty is the recommended treatment by open or laparoscopic approaches. Early versus late pyeloplasty is controversial in very young patients. A nephrectomy may be indicated if less than 10% renal function remains.

Ureteral Duplication

Ureteral duplication is the most frequent anomaly of the urinary tract and is twice as common in female as in male patients. The ureteral orifice of the upper renal segment drains inferiorly and medially to the orifice of the lower segment (Meyer-Weigert law). The orifice draining the upper segment is often obstructed,

P.245

whereas the orifice of the lower segment generally refluxes. Duplication is usually discovered on an IVU.

Ectopic Ureter

An ectopic ureter is one that opens in some location other than the bladder.

• 80% are associated with a duplicated system, usually in female patients.

• 20% are single ectopic ureters usually occurring in male patients with an absent hemitrigone.

• Most common sites for insertion of the ectopic orifice in female patients are the urethra, vestibule, and vagina, and present as urinary incontinence.

• Most common sites for insertion of the ectopic orifice in male patients are the posterior urethra and seminal vesicles, often remaining unrecognized until late in life.

Continuous incontinence in an otherwise normal female patient should suggest an ectopic ureteral orifice. Male patients present with urinary tract infections, not incontinence.

Diagnosis

An IVU with tomography and delayed films, VCUG, ultrasound, and cystourethroscopy should be obtained. Intravenous indigo carmine during urethroscopy can help locate the ectopic orifice. A DMSA renal scan may be helpful in differentiating function between the upper and lower poles. Approximately 10% to 20% of ectopic orifices will not be found without surgical exploration.

Treatment

Treatment is either partial nephroureterectomy of the nonfunctioning upper-pole component or pyelopyelostomy with only a distal ureterectomy if the upper pole functions. A nephrectomy may be necessary in a single system.

Ureterocele

A ureterocele is a congenital cystic ballooning of the terminal submucosal ureter. It is classified as simple or ectopic.

Simple (Orthotopic) Ureteroceles

This type represents about 30% of all ureteroceles and occurs primarily in adult men. The ureter is normally placed in the trigone. Patients present with infection, and reflux is uncommon.

P.246

Ectopic Ureterocele

Ectopic ureterocele represents about 70% of all ureteroceles, occurring mainly in girls, with a left predominance; 10% are bilateral. It arises from the dysplastic upper-pole ectopic ureter of a duplicated system with little or no function. The orifice is often at the bladder neck or within the urethra. It can obstruct the ipsilateral lower pole or contralateral ureter and occasionally the bladder neck. This is a serious anomaly, with children often seen in the first few months of life with infection.

Diagnosis

Ureteroceles are increasingly being discovered on prenatal ultrasound. Ureteroceles are easily visualized on the cystogram phase of an IVU. The classic nonopaque filling defect of the cobra-head or spring-onion deformity can be confused with a tumor, stone, blood clot, or gas in the rectum. A VCUG can assess for reflux (40%). Diagnosis is confirmed by cystoscopy. A renal scan should be performed to evaluate renal function.

Treatment

Treatment must be tailored to the patient's altered anatomy and physiology.

Simple ureteroceles can be approached intravesically, with excision and reimplantation of the distal ureter. Ectopic ureteroceles are approached like ectopic ureters. If upper-pole function is poor, an upper-pole partial nephrectomy is performed with partial or complete ureterectomy. Eventual reimplantation of the lower-pole ureter may be necessary if reflux is severe or persistent. A complete nephroureterectomy may be necessary if the entire kidney is nonfunctional.

Retrocaval Ureter

A retrocaval or circumcaval ureter is an uncommon congenital anomaly whereby the right ureter deviates medially behind the inferior vena cava, encircling the cava and passing in front of it, before resuming its normal lateral course to the bladder. Patients present with evidence of obstruction in the third or fourth decade of life.

Diagnosis

An IVU generally will not show the retrocaval part of the ureter. A retrograde ureterogram will typically demonstrate an S-shaped ureter coursing toward the cava at the point of obstruction.

P.247

Treatment

Surgical management entails ureteral division with ureteroureteral anastomosis.

Megaureter

Megaureter or big ureter is a term that most urologists use to refer to primary ureteral dilatation in the absence of extraureteral disease. However, the term has been extended to include the classification of all major ureterectasis with emphasis on differentiating obstructed from nonobstructed varieties. Most children with megaureter will present with urinary tract infection, hematuria, or a flank mass; 25% of cases are bilateral.

Classification

The international classification of megaureter includes three major categories:

• Obstructed megaureter can be from primary intrinsic ureteral obstruction, usually by an extravesical adynamic ureteral segment, or secondary to urethral obstruction as with valves, prolapsing ureterocele, calculi, granulomatous disease, or other extrinsic causes;

• Refluxing megaureter is from either primary intrinsic ureteral reflux or reflux secondary to bladder-outlet obstruction or neurogenic bladder;

• Nonrefluxing, nonobstructed megaureter is a congenital idiopathic ureteral dilatation often associated with megacalycosis.

Workup

Workup usually begins with an ultrasound and VCUG to determine the degree of ureterectasis and the presence or absence of reflux. Obstruction can be determined by a furosemide (Lasix) renal scan or IVU or a Whitaker test in the event of an equivocal scan.

Treatment

Most patients with primary megaureter have the nonrefluxing, nonobstructing type that needs no surgical intervention. These patients should be followed up, with surgery reserved for those with evidence of progressive renal parenchymal damage or recurrent infections. Primary obstructive megaureter requires surgical correction, commonly by tapering the lowermost 5 cm of ureter with reimplantation. Any and all extraureteral causes of obstruction should also be relieved. Refluxing megaureter can be

P.248

managed with either medical surveillance or operative correction (see Chapter 35).

Urachus

The urachus is a tubular structure extending from the anterior bladder wall to the umbilicus. It lies on the anterior abdominal wall between the two umbilical arteries in the space of Retzius between the peritoneum and transversalis fascia. It normally involutes into a solid cord by the fourth or fifth month of gestation.

Patent Urachus

A patent urachus is a rare congenital anomaly in which the urachus fails to involute, resulting in an open communication between the bladder and the umbilicus. It presents in the neonatal period with constant or intermittent leakage of urine from the umbilicus. The diagnosis can be confirmed by measuring creatinine of the discharge fluid, VCUG, fistulogram, or by instilling colored dye into the bladder. Spontaneous closure may occur if leakage is small; otherwise, complete excision of the tract is usually required.

Urachal Cyst

A urachal cyst develops in a partially obliterated urachus, usually in the lower third. It presents commonly in adult life with suprapubic pain, tenderness, fever, voiding symptoms, and a palpable mass. The diagnosis is made with ultrasound, IVU, CT, and VCUG. Treatment consists of incision and drainage or marsupialization with delayed excision.

Umbilical Sinus

An umbilical sinus is a chronically infected urachal cyst that drains to the umbilicus. The diagnosis is made by sinogram and cystogram. Treatment consists of antibiotics and excision of the sinus tract.

Bladder and Urethral Anomalies

Exstrophy Complex

Exstrophy is a rare congenital defect resulting in a spectrum of anomalies of the urogenital and musculoskeletal system secondary

P.249

to persistence of the cloacal membrane in utero. It occurs in approximately 1 in 30,000 live births, with a male predominance of 3:1. Three major subgroups represent different degrees of severity of the defect.

Cloacal Exstrophy (10%)

Cloacal exstrophy is the most severe and distressing of these defects, involving a massive defect of the anterior abdominal wall with exposed bladder, ileocecal bowel, and a short blind-ending colonic segment with imperforate anus. Myelomeningoceles are present in 50%. Management of these patients' severe problems has recently become more aggressive, with encouraging successes.

Classic Bladder Exstrophy (60%)

Classic bladder exstrophy presents as a protruding red mass in the suprapubic region, which is the exposed back wall and trigone of the bladder, and an epispadiac urethra leaking urine. Associated defects include a widely separated pubic symphysis and lower rectus muscles, frequent bilateral indirect inguinal hernias and retractile testes, and rectal prolapse in 15% to 20%. Upper tracts are generally normal.

Treatment

The prognosis for patients with classic bladder exstrophy is excellent, with normal life expectancies and good quality of life. All patients deserve an attempt at staged functional reconstruction, preferably in the first 48 hours of life to minimize bladder damage secondary to environmental exposure, and may avoid the need for iliac osteotomies. The most important part of their treatment is to refer them to a pediatric urologist who has experience with exstrophy immediately after birth.

Epispadias (30%)

Epispadias is the least severe defect with only an open urethra on the dorsum of the penis and a lesser degree of separation of the pubic symphysis. Approximately 90% will have vesicoureteral reflux, and 75% will present with incontinence.

Urethral Valves

Posterior Urethral Valves

Posterior urethral valves are the most common etiology of bladder-outlet obstruction in boys. They are congenital membrane-like structures located in the distal prostatic urethra covered by

P.250

transitional epithelium. They present with varying degrees of obstruction and are usually diagnosed within the first year of life. Infants with severe degrees of obstruction can present with a palpable bladder and bilateral hydronephrotic flank masses, urinary ascites, renal insufficiency, and infection.

Classification

Classification by H. H. Young, in 1919, into three types is still used.

• Type I valves are most common (95%). They appear as mucosal sails extending from either side of the distal verumontanum and attaching to the anterolateral walls of the membranous urethra.

• Type II valves are more proximal, arising from the verumontanum and passing toward the bladder neck. They are generally not believed to be a clinically significant cause of obstruction.

• Type III valves are membrane-like structures, usually with a small central perforation, and are not attached to the verumontanum.

Diagnosis

Diagnosis is increasingly made with prenatal ultrasound. Postnatal diagnosis is often made with ultrasound or a VCUG demonstrating a dilated and elongated posterior urethra and reflux in about 50%. A renal scan is often helpful. Direct visualization can be made during cystourethroscopy, along with noting bladder trabeculation.

Management

Preservation of renal function and prevention of infection must guide management. Immediate relief of obstruction should be undertaken without delay with catheter drainage. Healthy, uninfected children can have simple endoscopic destruction of the valves. Infants with evidence of severe obstruction, complicated by infection and persistent renal insufficiency after a period of catheter drainage, can be managed by primary high urinary diversion, as with cutaneous vesicostomy or loop ureterostomies, or even bilateral nephrostomy tubes. Delayed secondary endoscopic destruction can be performed later.

Anterior Urethral Valves

Anterior urethral valves are far less common and generally produce less damage from obstruction. Boys will typically present with signs of bladder-outlet obstruction, infection, or a palpable ventral urethral swelling at the penoscrotal junction during or after voiding. Urethral distention proximal to the valve will result in a saccular diverticulum in the bulbar urethra. Diagnosis is made with a VCUG. The valvelike obstruction can be relieved by endoscopic

P.251

electroresection; however, an associated diverticulum will generally require open excision and urethroplasty.

Penis

Hypospadias

Hypospadias is a congenital anomaly of the penis resulting from an incomplete development of the anterior urethra. The defect involves primarily an abnormal urethral opening, proximal to its normal location and often with an associated ventral chordee or curvature of the penis. It can be expected to occur in about 1 of every 300 live male births and is believed to have a multifactorial genetic mode of inheritance.

Familial Incidence

• 7% will have a father with hypospadias.

• 14% will have a brother with hypospadias.

• 21% will have a second family member with hypospadias.

Classification

Classification is simply by anatomic description of the meatal position (glanular, coronal, distal shaft, mid-shaft, proximal shaft, penoscrotal, scrotal, and perineal) and the degree of chordee (mild, moderate, and severe). The severity of the chordee usually increases with more proximal meatal openings. About 75% of cases can be expected to be of the glanular or coronal types.

Associated Anomalies

Undescended testes occur in about 10% of cases; inguinal hernias also occur in about 10% of cases. In the more proximal varieties of hypospadias, undescended testes occur in up to 30% of cases. Upper-tract anomalies occur in about 5%, and other system anomalies are even less common; however, their presence should alert one to evaluate the upper urinary tract fully. Intersex must be considered in patients with severe forms of hypospadias and ambiguous genitalia or nonpalpable testes.

Management

More than 100 variations of procedures are described for the surgical correction of hypospadias. All must contend with functional and plastic repair of the urethra and correction of chordee (orthoplasty). The optimal time for repair is between ages 6 and 12 months. Surgical

P.252

complications include urethrocutaneous fistula, persistent chordee, urethral stricture, diverticula, and meatal stenosis.

Epispadias

Epispadias is a rare congenital anomaly and the least severe form of the exstrophy complex. The malformed open urethra will lie on the dorsal surface of the penis, and diastasis of the symphysis pubis and rectus muscles commonly occurs. It affects predominantly males, 5:1. Vesicoureteral reflux is noted in 75%.

Classification

• Glanular epispadias (15%) is the rarest, with only a minor urethral defect on the dorsum of the glans penis.

• Penile epispadias (25%) is noted by an open distal urethra on the dorsal surface of the penis. Half can be expected to have a widened symphysis; however, continence is not a problem in these children.

• Penopubic epispadias (60%) will have the entire urethra open along the dorsal surface of the penis. The pubic symphysis is separated, and urinary incontinence is the rule. Dorsal penile chordee is common, and portions of the bladder may prolapse through the wide-open prostatic urethra. This is the most significant form of isolated epispadias noted in female patients and is referred to as subsymphyseal epispadias. The labia will not be fused, and the clitoris is bifid.

Management

Management is dictated by the degree of deformity. Glanular and penile epispadias will require elective urethroplasty and release of dorsal chordee. Penopubic epispadias with incontinence will require more-extensive reconstruction, similar to that for classic exstrophy, and usually includes a bladder-neck plasty, urethroplasty, and ureteral reimplants, as needed. Continence can be achieved in 60% to 80%.

Cryptorchidism

Cryptorchidism is one of the most common disorders in pediatric urology. It has been observed to occur in 3% of term infants and 30% of premature infants. By age 1 year, most of these testes will have spontaneously descended, leaving a true incidence of about 1% of the male population. Ten percent of cases are bilateral, 3%

P.253

of which will have one or both testes absent. The etiology is unclear; however, an association with low birth weight has been established. Many genetically inherited diseases have a high association with cryptorchidism, yet most cases of undescended testis are isolated with no evidence of a genetic component (see Chapter 11).

Imperforate Anus

The imperforate anus is a spectrum of congenital anomalies resulting from a failure of the normal descent of the urorectal septum in utero. The major clinical feature is the loss of a normal anal opening on the perineum, ranging between only minor anal stenosis to complete anal or rectal agenesis. Its incidence is reported at 1 in 5,000 births.

Two Major Clinical Subgroups

Two types of imperforate anus are recognized, based on the level of the blind-ending colonic pouch relative to the pelvic floor or levator ani muscles.

High or Supralevator Lesions

• High or supralevator lesions, primarily owing to rectal agenesis, have a high association with other anomalies.

• A high incidence of fistulas, usually rectourethral in male patients or rectovaginal in female patients, are noted.

• Associated urologic anomalies occur in 50%.

• A high incidence of upper-tract abnormalities (30%), including unilateral renal agenesis, hypoplasia, dysplasia, reflux, and ureteral obstruction, are found.

• Neuropathic bladders occur in 10%, secondary to congenital sacral abnormalities or from surgical dissection at rectal pull-through procedures (iatrogenic).

• Tracheoesophageal fistula or atresia is noted in approximately 10%.

• Lumbosacral spine abnormalities occur in 30% to 40%.

• Cardiac anomalies occur in 7%.

Low or Infralevator Lesions

Low or infralevator lesions, primarily owing to anal agenesis, have a much lower incidence of sacral or urologic abnormalities. Upper-tract abnormalities occur in only 10%.

P.254

Workup

Examine the perineum. Any evidence of meconium staining suggests a low lesion. Meconium in the urine suggests a high lesion. Obtain an abdominal renal ultrasound, renal scan, and VCUG, and perform cystourethroscopy before surgery. Be suspicious for hyperchloremic acidosis, particularly with high lesions.

Treatment

High lesions are best managed by a diverting colostomy and later rectal pull-through that is delayed for 6 to 12 months. Low lesions may be treated with a primary anoplasty. If reflux is significant, suppressive antibiotics, with or without cutaneous vesicostomy, may be necessary.

Prune-Belly Syndrome

The prune-belly syndrome (also known as Eagle-Barrett syndrome) is a rare congenital anomaly with an incidence of 1 in 50,000 live births that occurs almost exclusively in male patients (only 3% in female patients).

Major Characteristics

• Abdominal-wall defect from muscular deficiency ranging from partial hypoplasia to complete absence, giving the classic wrinkled appearance with bulging flanks

• Dilated and tortuous ureters, particularly at the lower end, with accompanying reflux in most cases

• Asymmetrical renal dysplasia and hydronephrosis

• Cryptorchidism with bilateral intraabdominal testes (orchiopexy is difficult because of short spermatic vessels)

• Wide and dilated bladder neck and posterior urethra secondary to prostatic hypoplasia urethral valves are rare; occasionally urethral atresia, usually associated with a patent urachus

• Large, thick-walled, irregularly shaped bladder, usually with a pseudodiverticulum at the dome and widely separated refluxing ureteral orifices

Associated Anomalies

• Frequent malrotation of the gastrointestinal tract and, occasionally, imperforate anus

P.255




• Cardiac abnormalities (in 10%), including ventricular septal defects, atrial septal defects, and tetralogy of Fallot

• Pulmonary complications such as pneumothorax and pulmonary hypoplasia secondary to severe renal dysplasia and oligohydramnios

Classification of Prune-Belly Syndrome

• Category I most severe form with oligohydramnios and pulmonary hypoplasia (poor prognosis; no surgical intervention)

• Category II classic features with uropathy and mild or unilateral renal dysplasia

• Category III mild external features and uropathy with stable renal function

Management

Most patients present in the neonatal period. Rarely are they a urologic emergency. Category I infants usually will not survive because of the severe pulmonary hypoplasia and renal dysplasia. Category III infants do well and need little urologic intervention. Management of category II infants focuses on their predisposition to urinary stasis and infection with potential renal deterioration.

Workup

Electrolytes, blood urea nitrogen (BUN), creatinine, urine cultures, chest radiograph, abdominal ultrasound, renal scan, and IVU should be performed early. A VCUG may be indicated if early surgery is considered; however, instrumentation of the lower urinary tract should be avoided because of the increased risk of infection.

Treatment

Maintain renal function and avoid infection. If urinary drainage is needed because of infection, then a cutaneous vesicostomy or cutaneous pyelostomy should be undertaken. Orchiopexy is usually attempted. Reduction cystoplasty is sometimes useful. Plastic repair of the abdominal wall improves body image. Long-term surveillance is mandatory.

Myelomeningocele

Myelodysplasia refers to a spectrum of congenital spinal anomalies caused by defects in neural tube closure. It occurs in 1 in 1,000

P.256

births in the United States. Failure of the posterior vertebral arches to fuse results in the development of a cystic meningocele, which contains dysplastic neural elements. The cord is frequently tethered to adjacent bony structures and does not recede with normal growth. Various degrees of myelomeningocele occur, from spina bifida occulta to spina bifida aperta. The resulting neurologic deficits include lower urinary tract dysfunction, with more than 90% of these patients having incontinence. Bladder and sphincter dysfunction occurs, including detrusor areflexia or hyperreflexia, with or without coordinated sphincter activity. The primary goals of management are to preserve renal function, prevent infection, and provide urinary control.

Workup

In addition to specific neurologic assessment, early evaluation of the upper tracts must be made in the neonatal period. Urinalysis, urine culture, and ultrasound should be obtained. If hydronephrosis is found (10%), a VCUG should be performed to look for vesicoureteral reflux. Urodynamic evaluation will eventually be necessary. Patients will need careful, periodic, close follow-up with urinalysis, culture, and imaging of the upper tracts with ultrasound or urography.

Management

Patients' disorders should be classified as either failure to empty or failure to store. Clean intermittent catheterization (CIC) is the most common mode of therapy for patients who fail to empty. Patients who fail to store can be managed with pharmacologic agents or surgical procedures to enlarge the bladder or increase outlet resistance (e.g., bladder neck plasty, slings, or artificial sphincters). Urinary diversion is a last resort. Antireflux procedures are also commonly needed.