Urethral diverticula

Introduction

For years, investigators who described their experience with urethral diverticula stated that more general awareness of this condition must prevail to improve its identification. Urethral diverticula can be difficult to diagnose. They are often overlooked as a source of recurrent urinary tract infections, chronic pelvic pain, and voiding dysfunction. The standard evaluation for all patients with acute and chronic pelvic disorders should include urethral diverticula in the differential diagnosis so that diagnosis and, ultimately, therapy will not be prolonged. Most patients present with a constellation of nonspecific irritative and obstructive voiding symptoms, which makes the correct diagnosis challenging. It has been shown that there is a significant delay in the diagnosis of female urethral diverticula in most patients. Even now, many women may have had this diagnosis overlooked as a cause for their pelvic disorders, and many of these patients have seen more than one pelvic health specialist, either in urology or gynecology, for their symptoms. Changes in the standard evaluation of women with reports of pelvic pain disorders should be instituted, so that with a thorough history, physical examination, and appropriately selected radiologic imaging, an exact diagnosis of the correct urethral pathology can be made.

Incidence

The true incidence of urethral diverticula is unknown, and the reported incidence varies. In 1967 Andersen showed that, of 300 women examined for cervical cancer, nine patients were diagnosed with urethral diverticula, for an incidence of 3%. The literature shows that the estimated incidence of urethral diverticula in women is 0.6% to 6%. It is the authors’ belief that an incidence of 6% is high, and that the true incidence is probably at the lower end of that range.

Etiology

The female urethra is a short tubular structure that is surrounded by multiple periurethral ducts and glands, the largest of which are the Skene’s glands; these are adjacent to the distal urethra and drain into the meatus. Congenital anomalies of the female urethra are rare. Infrequently, obstructing urethral valves have been identified; more often, an ectopic ureter is identified within the urethra, which may masquerade as a urethral diverticular communication site. reported a patient with an ectopic ureter that drained into a urethral diverticulum.

It is exceptionally rare to identify congenital urethral diverticula, although suburethral cysts have been identified in newborns. Even in those few instances, the urethral diverticula have ultimately been shown to be remnants of Gartner duct cysts. These diverticula are linked histologically to persistent cloaca, and even have been confused with possible urethral duplication. Nevertheless, the incidence of childhood female urethral diverticula is exceedingly low, and, as such, urethral diverticula are rarely diagnosed before the age of 20 years.

Female urethral diverticula are diagnosed most frequently in the third to fifth decades. Most diverticula are acquired, and a favored hypothesis regarding the etiology of female urethral diverticula begins in the paraurethral glands. Most diverticula of the female urethra are located dorsally or laterally and distally. It is believed that repeated infections and subsequent destruction of the paraurethral glands lead to abscess formation within the periurethral and urethral glands. These obstructed glands then rupture into the urethral lumen and remain as outpouchings off the urethra, which eventually epithelialize, becoming a true urethral diverticulum as opposed to a urethrocele or pseudodiverticulum.

Other possible etiologies of female urethral diverticula include obstetric trauma, trauma from urethral instrumentation, and postoperative urethral and vaginal surgery. Rarely, bulking agent injections for the treatment of stress urinary incontinence may result in a noncommunicating diverticulum with obstruction of a periurethral gland and persistent accumulation of secretions. Any patient who has had a bulking agent injection and subsequent pelvic imaging is more likely to have bulking agent adjacent to the urethra as opposed to a urethral diverticulum, as it is still uncommon to have an injection into a diverticulum or create the pseudoabscess.

Urethral diverticula are thought to be urothelial mucosa-lined sacs that lie outside the urethra within the periurethral fascia and lack surrounding muscle. They are prone to urine stasis and repeated infections. Inflammation and chronic irritation resulting from the presence of urine and debris may lead to malignant degeneration into adenocarcinoma, transitional cell carcinoma, or squamous cell carcinoma. More commonly, the stasis of urine causes repeated urinary tract infections and possible calculus formation. Recurrent urinary tract infections are a frequent problem in women with urethral diverticula; positive urine cultures (>100,000 colony-forming units/mL) often grow strains of Escherichia coli , other gram-negative bacilli, or gram-positive species such as Streptococcus faecalis .

Prolonged urinary stasis may result in the formation of calculi. Calculi in diverticula are uncommon, with stone formation occurring in only 1.5% to 10% of cases. Stones are usually caused by salt deposition, stagnant urine, and mucus from the epithelial lining of the diverticula.

The location, number, and extent of urethral diverticula have an impact on the choice of treatment. A classification system for female urethral diverticula described by considers location, number, size, configuration, communication, and continence factors. Although no classification system is commonly used, providing an accurate description of the diverticula under evaluation will facilitate therapy.

Presentation

Women come to their physicians with a host of symptoms, and unfortunately the patient’s description of each problem is not always textbook-clear. Therefore, the physician’s task is to identify, evaluate, and treat the pathology. A history of recurrent urinary tract infections, stress urinary incontinence, and incomplete voiding are some of the most common presenting symptoms in women with urethral diverticula ( Table 37.1 ). According to , the single most important problem is postmicturition dribbling. The addition of dysuria and dyspareunia complete the classic triad. These are all nonspecific problems, however, and are present less often than one may think. If the symptoms are also accompanied by urgency, urgency incontinence, frequency, and/or even a protruding vaginal mass, they are more highly suggestive of a urethral diverticulum. If pus can be expressed from the meatus with manual compression of the anterior vaginal wall, this strongly indicates the presence of a urethral diverticulum. reviewed their experience with diverse presentations of urethral diverticula and decided that, when symptoms mimic other disorders, and especially when they do not improve and respond with standard therapy, it is important to entertain the possibility of urethral diverticulum. In patients who have hematuria, difficulty voiding, and frank urinary retention, urethral diverticula may be the the cause of the voiding disorder, but these also represent more concerning findings for malignant changes within the diverticulum.

Many patients receive a variety of treatments that include antibiotics, anticholinergic and antidepressant medications, bladder hydrodistention, and urethral dilations for suspected pelvic disorders. Some of the more common presumed diagnoses are listed in Table 37.2 . In summary, in any case of persistent lower urinary tract symptoms unresponsive to therapy, one should exclude a urethral diverticulum.

Diagnosis

To establish the correct diagnosis in women with a myriad of symptoms, it is critical to perform a thorough history and physical examination. Included in a standard history are questions relating to stress urinary incontinence, urgency and urgency incontinence symptoms, and pad usage. Irritative voiding symptoms, such as frequency, nocturia, urgency, and dysuria, and obstructive voiding symptoms, such as poor urine stream, difficulty voiding, hesitancy, and double voiding, should be noted. A history of urinary tract infections, pyelonephritis, and hematuria should be queried. Obstetric history, neurologic history, and bowel patterns should be included in the questions. A complete medication list with allergies and medical and surgical histories are also important.

A focused genitourinary examination is performed with the patient in the lithotomy position. A half-speculum is placed into the vagina to expose the anterior vaginal wall. The urethra and bladder are then well-visualized, and the patient is asked to perform a Valsalva maneuver and cough, to evaluate for urethral hypermobility and stress urinary incontinence, as well as for the presence of a cystocele. Careful attention is given to palpation of the urethra, with attempts to express purulent material via the meatus and to evaluate for suburethral masses or tenderness. This step may be avoided in a patient with suspected acutely infected diverticulum to minimize systemic dissemination of bacteria. Not all patients will have a suburethral mass, and not all suburethral masses are urethral diverticula. The differential diagnosis of peri- or suburethral masses is extensive and includes urethral diverticulum, urethrocele, Skene’s gland abscess, Gartner duct cyst, ectopic ureterocele, vaginal wall inclusion cyst, vaginal leiomyoma, and other, less frequent diagnoses ( Box 37.1 ).

Postvoid residual volume measurement can be accomplished with an office ultrasound or with a urethral catheter. The catheterized urine specimen should be sent for urine culture. If the patient reports hematuria and irritative voiding symptoms, urine cytology should be obtained. Evidence of stress urinary incontinence may require urodynamic testing to assess the abdominal leak point pressure and to determine the need for a simultaneous sling with excision of the diverticulum and reconstruction of the urethra. It is important to distinguish stress incontinence from postvoid dribbling because dribbling will usually improve after diverticulectomy, whereas stress incontinence may persist or worsen. The use of urodynamics or perhaps videourodynamics may be helpful in discerning this. Furthermore, cystoscopy with a full bladder and subsequent close examination of the urethra with coughing may be sufficient to determine the etiology of leakage.

One must clinically suspect a urethral diverticulum to select the most appropriate procedures and imaging studies. Many patients with urethral diverticula undergo urodynamic testing to evaluate voiding dysfunction, in particular urinary incontinence symptoms, but not all patients will require urodynamic testing. Urethroscopy may help establish the diagnosis of urethral diverticula; it is easily performed, has minimal morbidity, and most often results in the correct diagnosis in experienced hands. Urethroscopy should be focused on the posterior wall in the 3 o’clock and 9 o’clock positions to try to identify the suspected communication sites. A standard rigid cystoscope with a zero-degree angle lens or a flexible cystoscope (authors’ preference) may be used to evaluate the urethra.

Radiologic imaging

In addition to history-taking, thorough physical examination, urodynamic testing, and cystourethroscopy, radiologic imaging has clearly enhanced the detection rate of urethral diverticula. When a female urethral diverticulum is suspected, judicious selection of imaging techniques should correctly establish the diagnosis and provide details that aid in surgical excision. Traditionally, evaluation to confirm the diagnosis of female urethral diverticula was performed with positive-pressure urethrography (PPUG) and voiding cystourethrography (VCUG). However, currently multiple modalities are available to identify and characterize female urethral diverticula, including PPUG, VCUG, ultrasonography, and magnetic resonance imaging (MRI).