Urethral Anomalies and Urethral Prolapse in Children

Lacuna magna

Lacuna magna, also known as sinus of Guérin, is a dorsal diverticulum in the roof of the fossa navicularis presenting either as a pit or a 4- to 6-mm sinus, dorsal and parallel to the urethra. This lesion is thought to arise embryologically from an incomplete fusion between the ingrowing ectoderm at the tip of the penis and the glandular urethra.

Urethral duplications

Urethral duplications are rare anomalies characterized as epispadiac, hypospadiac, and Y-type.[4, 5]  They may be either complete, if venting externally, or incomplete, in which case the connection with the urinary tract varies.

In complete duplications, the patient may void with a double stream. Epispadiac duplications are usually associated with significant dorsal curvature of the penis. The most common type of urethral duplication is the Y-type; individuals with Y-type urethral duplication have an orthotopic meatus and a perineal meatus, through which most of the urine passes. The etiology of these conditions is unknown.

Urethral duplications may be associated with other abnormalities (eg, anorectal malformations).[6]

Anterior urethral valves

Anterior urethral valves[7] (AUVs) are rare anomalies, occurring seven to eight times less frequently than posterior urethral valves (PUVs), but with consequences just as devastating.

These lesions can occur anywhere in the anterior urethra, and the valve mechanism is usually formed by an associated diverticulum; isolated valves formed by cusps or irislike diaphragms have also been reported. The diverticulum has been postulated to arise from incomplete formation of the ventral corpus spongiosum, an incomplete urethral duplication, or a congenital cystic dilation of a periurethral gland. However, these lesions are embryologically distinct from the much more common PUVs and occur distal to the urinary sphincter.

Megalourethra

Megalourethra can be described as a urethral diverticulum that affects the entire penile urethra. Two types, scaphoid and fusiform, have classic descriptions. Scaphoid megalourethras have an absence of corpus spongiosum, whereas fusiform megalourethras lack both spongiosum and corpora cavernosa. Often associated with lethal congenital anomalies, fusiform megalourethras are present in some stillborns; therefore, this finding has more academic than clinical pertinence.

Temporary obstruction during early development may be an etiologic factor in fusiform megalourethra. In the scaphoid type, in which failure of development of erectile tissue is present, a mesenchymal defect is suggested, akin to what is observed in prune belly syndrome.

Anterior urethral diverticula

Anterior urethral diverticula[7] occur in males and may involve the proximal part of the penile urethra and the distal part of the bulbous urethra. An underlying defect in the spongiosum is suggested, as observed in scaphoid megalourethra. An alternative possibility is that these lesions may result from the rupture of a periurethral cyst or a partial duplication of the urethra.

Urethral polyps

Urethral polyps are rare anomalies, characterized as benign urothelium-lined masses attached to a fibrovascular stalk arising from the verumontanum, presenting almost exclusively in boys. Urethral polyps' association to the verumontanum suggests the embryologic persistence of müllerian structures. Some of these polyps, diagnosed later in life, may represent acquired lesions.

Cowper duct cysts

Cowper duct cysts involve the Cowper glands, which are two paired periurethral structures located in the urogenital diaphragm. The Cowper glands are drained by ducts 2-3 cm in length that empty into the bulbous urethra through two small flush openings. These glands, homologous with the Bartholin gland in the female, secrete a clear fluid that functions as a lubricant and a coagulation factor for semen during ejaculation. Abnormalities of these glands and their ducts may result from obstruction and, less frequently, trauma and infection.

Urethral prolapse

Urethral prolapse is the complete protrusion of the urethral mucosa beyond the meatus in females. This is an uncommon condition observed particularly in prepubertal black and Latin American girls. An increased incidence has been reported in children from the lower socioeconomic strata.

This condition is thought to result from poor attachments between the longitudinal and circular oblique smooth-muscle layers and the mucosa of the urethra in association with recurrent episodes of increased intra-abdominal pressure. Other contributing factors (eg, trauma, malnutrition, urinary and vaginal infections, and urethral mucosa redundancy) have been postulated in the etiology of this condition.[8]

Most conditions discussed in this article are infrequent or rare.

Although the dorsal urethral diverticulum in the roof of the fossa navicularis (ie, lacuna magna) may be present in approximately 30% of examined boys, this condition is rarely symptomatic. 

Urethral duplications are rare; only 150 cases had been reported in the literature prior to 1986.

Each year, an estimated five of every 1000 boys (of all races and ethnicities) born in the United States have hypospadias, making it one of the most common birth defects.[9, 10]  It has been estimated that epispadias with exstrophy occurs about once every 30,000 births, isolated epispadias without exstrophy in males about once in 120,000, and isolated epispadias in females about once in 500,000.[11]

The ratio of the incidence of AUVs to that of PUVs is 1:8; PUV occurs in 1 in 8000 to 1 in 25,000 live male births.

Fewer than 50 cases of megalourethra had been reported in the literature by 1993; the scaphoid type is more common. Megalourethras have often been associated with other severe anomalies, such as prune belly syndrome, cloacal malformations, and the VACTERL (vertebral, anal, cardiac, tracheal, esophageal, renal, and limb) association of congenital anomalies.

Diverticula of the anterior urethra are uncommon but are the second most common form of congenital urethral obstruction, after PUVs, in infants and children. 

Both Cowper duct cysts and congenital urethral polyps are quite rare.

Urethral prolapse has an estimated incidence of 1 in 3000 and is most common in young black or Latin American girls.

Associated anomalies determine the prognosis of patients with fusiform megalourethra. Although obstructive lesions may be successfully managed with various operative techniques, prognosis ultimately depends on renal damage secondary to obstruction and infection.

Because lacuna magna, anterior urethral valves (AUVs), congenital urethral polyps, and Cowper duct cysts present with quite similar complaints, careful consideration of these urethral anomalies, along with a complete physical examination and appropriate imaging studies, is required to reach the correct diagnosis.

Children with lacuna magna can report intermittent postvoid spotting, hematuria, dysuria, or severe pain in the vicinity of the glans during voiding.

Most patients with incomplete urethral duplications are asymptomatic; however, those with complete duplications may complain of urinary incontinence, discharge from the accessory urethra, double urinary stream, or symptoms of urinary tract infections (UTIs).

Infants with AUVs present with severe bladder outlet obstruction. Older children present with irritative voiding symptoms, weak stream, incontinence, dribbling, or UTIs. Emptying of the valve diverticulum or overflow incontinence may cause dribbling.

Diverticula of the anterior urethra can also present in infancy with urinary obstruction or retention and, later, as UTIs or dribbling.

Symptoms of congenital urethral polyps in children include intermittent bladder obstruction, hesitancy, hematuria, dysuria, splayed urinary stream, and UTI.

Cowper duct cysts are manifested by hematuria, passage of mucous plugs, dysuria, hesitancy, intermittent obstructions, and postvoid dribbling. These symptoms become more apparent in adolescent males.

Female patients with urethral prolapse usually present with vaginal bleeding,[12, 13, 14] spotting, dysuria, urinary frequency, introital pain, and, occasionally, urinary incontinence or retention.

Many of the conditions discussed in this article may be suggested by the history; however, the anomalies may not be obvious upon physical examination. Some of these conditions are clearly evident.

In patients with urethral duplications, dorsal curvature of the penis (in the epispadiac type), double stream, or multiple meatus can be present.

In children with AUVs and congenital urethral diverticula, the urethra may bulge on the ventral aspect of the penis while voiding and the stream may be weak.

In boys with fusiform megalourethra, the penis is flabby and soft because of the absence of corpora cavernosa, and the urethra balloons during micturition. Unfortunately, fusiform megalourethra is usually an autopsy finding because this condition is often associated with stillbirths.

Occasionally, urethral polyps prolapse through the meatus, or a perineal mass can be palpated in patients with a Cowper duct cyst.

The physical findings in girls with urethral prolapse are quite striking. A doughnut-shaped anterior vulvar mass completely surrounding the urethra is pathognomonic. Urethral prolapse is the only condition in which a circumferential mass surrounding the urethra can be found. The mass appears as an edematous fleshy rosette that may become ulcerated, necrotic, or gangrenous.

Demonstration of the meatus in the center of the edematous tissue is important for diagnosis. Finding the urethral meatus is critical in making the diagnosis of urethral prolapse. The meatus can be located by inspecting the urethra, placing a Foley catheter, or watching the child void. 

Morbidity of the sinus of Guérin (ie, lacuna magna) is limited to those few symptomatic patients who present with dysuria, hematuria, or hematospermia.

Although most patients with incomplete urethral duplications are asymptomatic, patients with complete duplications can present with urinary obstruction, incontinence, infection, or double stream.

Epispadiac duplications are associated with a significant dorsal curvature of the penis. In general, associated upper urinary tract anomalies are infrequent but should be investigated.

In at least 50% of patients with AUVs, associated hydronephrosis or vesicoureteral reflux (VUR) is present. Although considerably more attention has been focused on posterior urethral valves (PUVs), AUVs can be just as obstructing and devastating, in some cases leading to chronic renal failure or end-stage renal failure.

The prognosis for patients with megalourethra depends on the number and severity of the associated anomalies. Often, patients with fusiform megalourethras have associated lethal congenital malformations.

Urethral diverticula, polyps, and Cowper duct cysts are benign conditions that may cause urinary retention, hematuria, irritative voiding symptoms, dribbling, or urinary tract infections (UTIs). Because these lesions may be obstructive, evaluation of the upper urinary tracts is essential.

Urethral prolapse may result in dysuria, hematuria, blood spotting on the underwear, or bleeding and, if unattended, can lead to necrosis of the prolapsed portion of the urethra.

Perform a complete urinalysis and urine culture for any child who presents with symptoms suggestive of a urinary tract infection (UTI). Diagnosis is made on the basis of the presence of both pyuria and at least 50,000 colonies/mL of a single uropathogenic organism in an appropriately collected specimen of urine.[15, 16]

Hematuria in the absence of infection and the evaluation of urinary incontinence are beyond the scope of this article but merit thorough investigation (see Hematuria, Urinary Incontinence).

In cases of urethral prolapse, obtaining a culture from the prolapsed mass or from any associated vaginal discharge may be useful.

Voiding cystourethrography (VCUG) and renal and bladder ultrasonography (US) have generally been considered to be indicated for all patients with culture-proven UTIs. According to the 2011 American Academy of Pediatrics (AAP) guideline on diagnosis and management of the initial UTI in febrile infants and children aged 2-24 months,[15] which was reaffirmed in 2016,[16] VCUG is not recommended routinely after the first UTI but is indicated if renal and bladder US reveals hydronephrosis, scarring, or other findings suggestive of high-grade vesicoureteral reflux (VUR) or obstructive uropathy; if other atypical or complex clinical circumstances are present; or if there is a recurrence of a febrile UTI.

In the absence of UTIs, most suspected urethral lesions can be documented with VCUG or retrograde urethrography (RUG).[17]

Evaluation of the upper tracts with US, nuclear scanning, or intravenous pyelography (IVP) is particularly important in patients with anterior urethral valves (AUVs), urethral duplications, megalourethras, urethral diverticula, polyps, or Cowper duct cysts because various degrees of obstructive uropathy may be present and may affect the upper urinary tract and kidneys.[18, 19]

US examinations during the second trimester of pregnancy can help detect some anomalies in the fetal urinary tract.[20]

In patients with megalourethras and urethral duplications, additional imaging studies may be necessary because of the high incidence of associated anomalies.

Patients with urethral prolapse do not require further evaluation of their urinary tracts. However, if the diagnosis is in question, performing bladder US to exclude a bladder rhabdomyosarcoma is reasonable.

Magnetic resonance imaging (MRI) is playing an evolving role in the evaluation of stress urinary incontinence.[21]

Cystoscopy can be used to clarify a diagnosis or for therapeutic purposes.

Treatment of urethral prolapse ranges from conservative therapy (eg, applications of antibiotic ointments, estrogen creams, sitz baths, herbal remedies, oral antibiotics) to various surgical techniques.

Although some medical professionals have advocated conservative measures, the author feels that these measures should be used in the milder cases of urethral prolapse or when general anesthesia is contraindicated because the results of medical treatment are less predictable than those of surgery. However, no prospective data have compared cost analysis of conservative treatment versus surgical intervention.[22] Certainly, when the urethral mucosa appears gangrenous or necrotic, conservative measures are not appropriate.

Treatment of the other urethral anomalies discussed in this article is mostly operative.

Urinary tract infections (UTIs) are managed with conventional treatment. For pyelonephritis, conventional treatment typically includes an intravenously administered second-generation cephalosporin (eg, cefotaxime) and antibiotics adjusted later, according to sensitivities.

Treatment of urethral duplications is individualized. In most instances, the ventral urethra is the functional one. Two thirds of patients require surgery. A decision as to which urethra to preserve (usually the ventral) must be made. Hypospadias and epispadias are treated with standard techniques (see Hypospadias, Exstrophy and Epispadias). Unknowing excision of the functional urethra may result in urinary retention or incontinence.

Managing anterior urethral valves (AUVs) is a subject of controversy. Although Rushton et al recommended cutaneous vesicostomy in the neonate, followed by endoscopic valve ablation when the child is older,[23] others have suggested two-stage urethroplasty, with the first stage to be performed in the neonatal period.

Treatment of megalourethra follows the principles of surgery for hypospadias.

Endoscopic resection is the treatment of choice for urethral polyps. Conversely, endoscopic marsupialization is used to correct urethral diverticula, sinus of Guérin anomalies, and Cowper duct cysts.[24]

Urethral prolapse is managed best with a modification of the Kelly-Burnam operation in which prolapsed mucosa is excised and the mucocutaneous junction is reapproximated with absorbable sutures.[25] Ligation of the prolapsed mucosa over a Foley catheter is discouraged because of a higher rate of complications (eg, infection, recurrence, and prolonged need for analgesics).

Perioperative antibiotics are used in all open and endoscopic procedures for the treatment of urethral anomalies and urethral prolapse.

In general, treatments are safe and effective, and complications are infrequent. The following can complicate the operative repair of urethral anomalies and urethral prolapse:

• Bleeding
• Infection
• Urinary retention
• Incontinence

Consult a pediatric urologist for children in whom urethral anomalies or urethral prolapse are suggested.

Consult a pediatric nephrologist when associated obstructive uropathy is present (particularly in patients with AUVs).

After any operation, a follow-up visit should be scheduled to evaluate surgical outcome.

In patients without obstructive uropathy, progress can be monitored by focusing on the symptomatology.

When significant obstruction is present, follow-up care should include serial renal ultrasonography (US) and at least one voiding cystourethrography (VCUG) or retrograde urethrography (RUG) to document anatomic relief of the obstruction and monitoring of the upper urinary tract.

Start treatment of pyelonephritis with a broad-spectrum intravenous antibiotic, which is modified according to sensitivities. Continue until the patient has been afebrile for 48 hours and the WBC count has normalized, at which time therapy can be switched safely to oral therapy.

Class Summary

These agents are used to treat pyelonephritis. Conventional treatment typically is initiated with a second-generation intravenous cephalosporin (eg, cefotaxime). Antibiotic regimens are adjusted later according to culture and sensitivities.

Cefotaxime (Claforan)

Third-generation cephalosporin with gram-negative spectrum. Lower efficacy against gram-positive organisms. Arrests bacterial cell wall synthesis, which, in turn, inhibits bacterial growth.

Ampicillin (Marcillin, Omnipen, Polycillin, Principen, Totacillin)

Usually used in combination with an aminoglycoside. Increased resistance to Escherichia coli is beginning to emerge. Exerts bactericidal activity against susceptible organisms.

Gentamicin (Garamycin, Gentacidin)

Aminoglycoside antibiotic for gram-negative coverage. Used in combination with both an agent against gram-positive organisms and one that covers anaerobes.