Urethra abnormalities

Urinary incontinence can result from abnormalities within (intrinsic to) and outside of (extrinsic to) the urinary tract. Within the urinary tract, abnormalities may occur in the urethra (including the bladder outlet and urinary sphincters), the bladder, or a combination of both structures. Focusing on abnormalities in these two structures, a simple classification scheme emerges for all but the rarest intrinsic causes of UI. Accurate diagnosis and classification of UI type is critical to the selection of appropriate drug therapy. 

Bladder tumor-associated antigen (BTA), a human complement factor H, is produced by bladder cancer cells (men two to three times as often as women). Cancer cells are sometimes seen in urine samples by microscope cytoscopy (examination of the bladder with an instrument inserted into the urethra), which can reveal abnormal areas. Biopsy is needed to confirm the diagnosis. Early stage cancer confined to the bladder wall can often be removed with a cytoscope. If several tumors are present, they are removed by infusing the bladder with a solution containing bacteria able to stimulate the immune system. 

Lower tract infections include cystitis (bladder), urethritis (urethra), prostatitis (prostate gland), and epididymitis. Upper tract infections (such as pyelonephritis) involve the kidney and are referred to as pyelonephritis. Uncomplicated UTIs are not associated with structural or neurologic abnormalities that may interfere with the normal flow of urine or the voiding mechanism. Complicated UTIs are the result of a predisposing lesion of the urinary tract such as a congenital abnormality or distortion of the urinary tract, a stone, indwelling catheter, prostatic hypertrophy, obstruction, or neurologic deficit that interferes with the normal flow of urine and urinary tract defenses. 

Intrauterine growth retardation and anomalies of the fetal urinary tract, such as bilateral renal agenesis or obstruction of the urethra, are associated with oligohydramnios, an abnormally low amniotic fluid volume. Increased fluid volume is known as hydramnios (also termed polyhydramnios). Conditions associated with hydramnios are as diverse as maternal diabetes mellitus, severe Rli isoimmune disease, fetal esophageal atresia, multifetal pregnancy, anencephaly, and spina bifida. 

Simply stated, UI may occur only as a result of abnormalities of the urethra (including the bladder outlet and urinary sphincter) or the bladder, or from a combination of abnormalities of both structures. Abnormalities may result in either overfunction or underfunction of the bladder and/or urethra with the resulting development of UI. While this simple classification scheme excludes extremely rare causes of UI such as congenital ectopic ureters and urinary fistulas, it is useful in gaining a working understanding of the condition. 

CT has a limited role in the evaluation of the urethra. Certain urethral abnormalities such as calculi or diverticula may be incidentally discovered at CT performed for other indications. CT is useful in patients with pelvic trauma (Chou et al. 2005) and associated urethral injuries and for staging of urethral carcinoma. CT virtual cystoscopy and voiding urethrography can be indicated in patients with complex urethral strictures and malformations. 

When the shape is abnormal or the bladder is empty, capacity should not be inferred from US measures (Bis and Slovis 1990). The transperineal approach can be useful to visualize dilated posterior urethra in boys with valves (Teele and Share 1997). Finally, ureteral jets into the bladder can be detected with color Doppler (Leung et al 2007). 

Fig. 1.1.6. VCU in a 7-year-old boy who complained of dys-uria. Oblique view during micturition. Slightly irregular bladder cannot be interpreted as abnormal during micturition. Bladder diverticulum (the same was shown on the opposite side). Moderate dilatation of the posterior urethra. Valves were suspected. Cystoscopy confirmed the diagnosis, and coagulation was performed. However, the orifices of the diverticula were not seen by the surgeon...

Retrograde urethrography is rarely indicated, and retrograde or suprapubic VCU should be preferred in most patients. Such an examination is usually performed to rule out a ruptured urethra in an adolescent. A Foley catheter is inserted in the distal urethra. The balloon is then inflated in the fossa navicularis, and the urethra is slowly and retro-gradely injected. Lateral and oblique pictures are taken. In most instances, the posterior urethra is not opacified. This should not be considered abnormal. 

Posterior urethral valves consist of abnormal mucosal folds between the urethral wall and the distal end of the verumontanum. The classification established by Young at the beginning of the twentieth century appears questionable from an endoscopic perspective (Dewan et al. 1992). Young had identified three types of valves. Type I was described as a bicuspid valve radiating distally from the posterior edge of the verumontanum to the anterior aspect of the proximal membranous urethra. Type 1 valves are by... 

Extremely rare in childhood, the urethral polyp is usually solitary and consists of a pedunculated structure, originating from the posterior urethra, developing in the bladder neck, which can prolapse in the urethra during micturition (Foster and Garrett 1986). Hematuria, nonneurogenic bladder-sphincter dysfunction and infection may reveal the abnormality. On ultrasound, it appears echo-genic. The main differential diagnosis of urethral polyp is an ectopic ureterocele that has ruptured either spontaneously (Fig. 6.8) or after endoscopic... 

Fig. 6.7. a VCU in a 7-year-old boy with dysuria, showing extrinsic compression of the urethra due to abnormal sphincter contraction during micturition. This functional anomaly should not be mistaken for posterior urethral valves. Urody-namic studies favor dysfunctional voiding with bladder-sphincter dyscoordination during voiding. Biofeedback physiotherapy was carried out. Clinical outcome was favorable, b Follow-up VCU shows normalization of urethral anatomy during... 

A great variety of urethral abnormalities may be found, most of them in boys. Evaluation is based on VCU or urethrography. Endoscopy is often useful. Normal variants should be kept in mind in order to avoid misinterpretation. For example, compression of the pendulous urethra by a nonopaque urinal and proximal dilatation is a frequent cause of error (Rink and Mitchell 1990). 

For the evaluation of children with symptoms of nonneurogenic bladder-sphincter dysfunction by ultrasound, a careful examination of the urinary bladder has to be performed in particular. Not only structural abnormalities have to be searched for bladder wall thickness, bladder volume and residual urine volume after voiding have to be assessed. Similar as described before for the modified VCU technique, the bladder base and bladder neck respectively have to be observed carefully by ultrasound as well. A transient opening of the bladder neck together with uninhibitetd detrusor contractions with filling of the posterior urethra up to the con-... 

The commonest congenital abnormality of the urethra is posterior urethral valves, which may result in the most severe renal disease in childhood (see also Sect. 6.2). This condition requires regular followup with imaging. Antenatal insertion of a double-J stent between the fetal bladder or dilated collecting system of the kidneys and the amniotic cavity under sonographic guidance allows decompression of the urinary tract. However, as this procedure... 

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