Urodynamic studies

For UUI, the preferred diagnostic tests are urodynamic studies. Urinalysis and urine culture should be performed to rule out urinary tract infection. 

Placebo-controlled urodynamic studies in men with BPH have unequivocally demonstrated that finasteride produces objective improvement in bladder oudet obstruction (Tammela and Kontturi, 1993 Kirby et al., 1992 Abrams et al., 1999 Schaffer et al., 1999). Singlecenter studies using detrusor pressure to measure outflow obstruction demonstrated that the majority of finasteride-treated patients were shifted out of the obstructed range as compared with placebo patients over a 3- to 6-month study period (Tammela and Kontturi, 1993 Kirby et al., 1992). Similar results were reported in a 1-year multicenter study in men with BPH (Abrams et al., 1999). Moreover, this study demonstrated that the magnitude of the improvement in bladder oudet obstruction and maximal urinary flow rate with finasteride over placebo increases with increasing prostate volume. Long-term (1-year), open-label follow-up evaluation for this study demonstrated further reductions in bladder oudet obstruction with chronic finasteride therapy (Schaffer etal, 1999). 

Hellstrom P, Lukkarinen O, Kontturi M. Bladder neck incision or transurethral electroresection for the treatment of urinary obstruction caused by small prostate A randomized urodynamic study. Scand J Urol Nephrol 1986 20 187-192. 

Urodynamic studies are the gold standard for diagnosis. Also urinalysis and urine culture should be negative (rule out urinary tract infection as cause of frequency). 

Thevaraja AK, Batra YK, Rakesh SV, Panda NB, Rao KL, Chhabra M, et al. Comparison of low-dose ketamine to midazolam for sedation during pediatric urodynamic study. Paediatr Anaesth May 2013 23(5) 415-21. 

In a first step, bladder and sphincter function are completely evaluated urodynamically during the phases of bladder filling, storage, and voiding. Prior to instrumentation an initial uroflowmetry is performed. The urodynamic study comprises continuous monitoring of rectal pressure, sphincter electromyogram, total bladder pressure, and sub-... 

In a second step the video-urodynamic study itself is performed. Fluoroscopic video-cystourethrography is performed intermittently during the filling and storage phases. Fluoroscopy of voiding demands that micturition be performed in the erect position in older children, and for this a simple funnel-shaped device to fit the female perineum is utilized. 

Fig. 1.4.1. Example of a video-urodynamic study. Blue line indicates total bladder pressure, red line rectal pressure, green line subtracted bladder pressure (detrusor pressure), white line electromyogram, dark blue line urinary flow. Vertical white line indicates time of fluoroscopic image...

Continence is often a problem in children and adolescents with a history of obstructive posterior urethral valves. Urodynamic studies are sometimes helpful to evaluate vesical and sphincter functions. Growth of the prostate gland during puberty often yields transient or definite improvement (Pfister et al. 1996). 

The clinical presentation is completely different in older children. The main complaint is usually dys-uria or infection (Fig. 6.6). Megacystis and thickening of the bladder wall are less frequent. Kidneys are usually normal, as is renal function. The differential diagnosis should include the other causes of bladder outlet obstruction (see below) and functional disorders such as dysfunctional voiding with severe bladder-sphincter dyscoordination. Both VCU and urodynamic studies can be diagnostic (Fig. 6.7). In case of valves, there is reduced urinary flow with no reinforcement of the perineal electric activity. 

Epispadia is part of the heterogeneous exstrophy-epispadia complex. It may occur in males and females. Widening of the pubic symphysis is usually associated. Continence is variable in those patients, so imaging and urodynamic studies in these patients should be directed towards this handicap and the detection of associated anomalies. Duplication of the bulbous urethra is extremely rare. It may be complete or blind-ended, ventral or dorsal (Barbagli et al. 1996). Finally, megalourethra (Stephens and Fortune 1993) is an enlargement of the pendulous urethra with no evidence of distal obstruction. It... 

Urodynamic studies coupled to a VCU are mandatory for the proper management of severely affected patients (Potter et al. 1986 Sillen 1999a Pfister 1999). On VCU, the bladder wall appears trabecu-lated and thickened, diverticula maybe present, the urethra is large (spinning top urethra), and the bladder neck appears tightened (Baunin 1993). 

Hoebeke P, Van Laecke E, Van Camp C et al (2001) One thousand video-urodynamic studies in children with non-neurogenic bladder sphincter dysfunction. BJU Int 87 575-580... 

A standardized protocol for the evaluation of the urinary tract must be established in every radiological department caring for neonates, infants and children with myelodysplasia. Such a protocol might be as follows After the myelomeningocele has been repaired and the hydrocephalus has been relieved by a shunt device, ultrasound studies of the kidneys and the bladder should be performed. During the first 6 weeks of life, a video-urodynamic study, if available, or a modified VCU study must be performed. In hospitals where only urodynamics is available, we suggest a modified VCU study as well. 

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