Topic 2: Congenital defects

—Congenital urinary tract anomalies
—Learning outcomes: outline the clinical manifestation Dx & Rx of congenital abnormalities
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—They account for 20% of all significant anomlies
§Its incidence is ↑ in newborns with a single umbilical artery.
§In true agenesis, the ureter and the ipsilateral bladder hemitrigone are absent. The contralateral kidney undergoes compensatory hypertrophy, to some degree prenatally but primarily after birth. because the wolffian duct is absent.
—Renal dysgenesis:
—dDysplasia,
—Hypoplasia, and
—cystic anomalies.
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— Dysplasia is a histologic Dx & refers to focal, diffuse, or segmentally arranged primitive structures, specifically primitive ductal structures, resulting from abnormal metanephric differentiation.
—multicystic kidney is a congenital condition in which the kidney is replaced by cysts and does not function, and may result from ureteral atresia
—polycystic kidney d’se is an inherited disorder that may be autosomal recessive or autosomal dominant & affects both kidneys  Multicystic kidney is unilateral and is not inherited.
—Bilateral multicystic kidneys are incompatible with life.
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—Renal hypoplasia refers to a small nondysplastic kidney that has fewer than the normal number of calyces and nephrons.
—The term encompasses a group of conditions with an abnormally small kidney and should be distinguished from aplasia, in which the kidney is rudimentary.
—If the condition is unilateral, the Dx usually is made incidentally during evaluation for another urinary tract problem or hypertension.
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—Bilateral hypoplasia usually presents like chronic renal failure & is a leading cause of end-stage renal disease during the first decade of life.
—Hx  of polyuria & polydipsia is common.
—Urinalysis results may be normal.
—In a rare form of bilateral hypoplasia called oligomeganephronia, the number of nephrons is markedly reduced and those present are markedly hypertrophied.
—Vesicoureteral Reflux
—Retrograde flow of urine from the bladder to the ureter & renal pelvis
—The ureter normally is attached to the bladder in an oblique direction, perforating the bladder muscle (detrusor) laterally and proceeding between the bladder mucosa and detrusor muscle, creating a flap-valve mechanism that prevents reflux .
—Reflux occurs when the submucosal tunnel between the mucosa and detrusor muscle is short or absent. Reflux usually is congenital, occurs
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—Clinical manifestation
—80% are female, & the average age at dx is 2–3 yr.
—.Primary reflux also may be discovered during evaluation for prenatal hydronephrosis.
—Reflux resolves in most prenatally diagnosed patients after birth
—repeated renal ultrasonographic examinations are indicated after birth to demonstrate resolution of the hydronephrosis.
—Rx
—Antibiotic prophylaxis
—surgery
—Obstruction of the urinary tract
—can be either congenital (anatomic) or caused by
—trauma,
—neoplasia,
—calculi,
—inflammatory processes, or surgical procedures,

Obstructive lesions occur at any level from the urethral meatus to the calyceal infundibula

—The pathophysiologic effects of obstruction depend on its level, the extent of involvement, the child's age at onset, and whether it is acute or chronic
—Causes of obstruction
—Infundibula
—Congenital  
—Calculi  
— Inflammatory (tuberculosis)  
—Traumatic  
—Postsurgical  
—Neoplastic
—Renal pelvis
—Congenital (infundibulopelvic stenosis)  
— Inflammatory (tuberculosis)  
—Calculi  
—Neoplasia (Wilms tumor, neuroblastoma
—Uteropelvic junction
—Congenital
—stenosis  
—Calculi  
—Neoplasia  
— Inflammatory  
—Postsurgical
—Causes of obstruction in the ureter
—Congenital
—Obstructive megaureter  
—Midureteral structure  
—Ureteral ectopia  
—Ureterocele  
—Retrocaval ureter  
—Ureteral fibroepithelial polyps 
—Ureteralvalves  
—Calculi , Postsurgical  
—Extrinsic compression  
—Neoplasia (neuroblastoma, lymphoma, and other retroperitoneal or pelvic tumors)  
—Inflammatory (Crohn disease, chronic granulomatous disease)  
—Hematoma, urinoma , Lymphocele  
—Retroperitoneal fibrosis
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—Bladder outlet & Urethra
—Bladder dysfunction (functional obstruction)  
—Posterior urethral valves
—  Anterior urethral valves  
—Diverticula  
—Urethral strictures (congenital, traumatic, or iatrogenic)  
—Urethral atresia  
—
—Ectopic ureterocele  
— Meatal stenosis (males)  
—Calculi   Foreign bodies  
—Phimosis  
—Extrinsic compression by tumors  
—Urogenital sinus anomalies
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—Clinical manifestation
—Obstruction of the urinary tract generally causes
—hydronephrosis, which typically is asymptomatic in its early phases.
—A renal mass 
— upper abdominal or flank pain on the affected side
—Pyelonephritis
—
—An upper urinary tract stone may occur, causing abdominal and flank pain and hematuria.
—With bladder outlet obstruction, the urinary stream may be weak; urinary tract infection (UTI) is common.
—Many of these lesions are identified by antenatal ultrasonography; an abnormality involving the genitourinary tract is suspected in as many as 1 in 100 fetuses.
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Obstructive renal insufficiency can manifest itself by
—FTT, vomiting, diarrhea, or
—other nonspecific signs and symptoms.
—In older children,
—infravesical obstruction can be associated with overflow urinary incontinence or
—Diagnosis
—Renal U/S
—Micturating cystourethrogram
—Excretory urogram
—Radioisotope studies.
—Computed tomography
—ECTOPIC URETER
—A ureter that drains outside the bladder.  Girls : boys = 3:1 and
—usually is detected prenatally.
—The ectopic ureter usually drains the upper pole of a duplex collecting system (two ureters).
—In girls, approximately 35% of these ureters enter the urethra at the bladder neck,
—35% enter the urethrovaginal septum,
—25% enter the vagina, and a few drain into the cervix, uterus,.
—Often the terminal aspect of the ureter is narrowed, causing hydroureteronephrosis.
—
—A poor urinary stream.
—Acute ureteral obstruction causes flank or abdominal pain;
—there may be nausea and vomiting.
—Chronic ureteral obstruction can be silent or can cause vague abdominal or typical flank pain with increased fluid intake.
—A ureterocele is a cystic dilatation of the terminal ureter and is obstructive because of a pinpoint ureteral orifice
—Prune-belly syndrome.
—also called triad syndrome or Eagle-Barrett syndrome, occurs in approximately 1 in 40,000 births;
—95% of affected individuals are male.
—The c’c asso. of deficient abdominal muscles, undescended testes, and urinary tract abnormalities
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—Anomalies of the penis
—Meatal stenosis
—Hypospadias
—Chordee (ventral curvature) or hood’
—Phimosis refers to the inability to retract the prepuce. At birth, phimosis is physiologic
—Paraphimosis occurs when the foreskin is retracted past the coronal sulcus and the prepuce cannot be pulled back over the glans.
—Agenesis of the penis
— Undescended testis (cryptorchid)
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—DDX of scrotal swelling in a newborn
—Hydrocele    Inguinal hernia (reducible)    Inguinal hernia (incarcerated)[*]    Testicular torsion[*]    Scrotal hematoma    Testicular tumor    Meconium peritonitis    Epididymitis[*
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