ABSTRACT
Answer: (d) Male newborns usually require a 5F feeding tube for urodynamic evaluation. We try to take care to avoid overly large catheters in newborns, which can obstruct the urethra and produce an abnormally high leakpoint pressures, as fluid tries to leak around the catheter. (Page 753)
5. An 8-year-old girl was referred for problems of infrequent voiding and constipation. Her history is consistent with dysfunctional elimination syndrome. Her imaging studies are normal. A urodynamic investigation was performed which showed bladder capacity of 450 ml and a bilateral grade 1 reflux. Her capacity pressure was 18 cmH 2 O. Her initial management would include:
(a) Bilateral subureteric Deflux injections (b) Bladder augment (c) Bowel management and biofeedback (d) Bilateral ureteral reimplants
Answer: (c) (Figure 51.12, page 757)
6. A 14-year-old male has a history of spina bifida. He managed his bladder with clean intermittent catheterizations since he was 3 years old. He takes 20 mg of oxybutinin XL in the morning and catheterizes every 2 – 3 h. At night he uses an overnight drainage bag. Previous urodynamics have shown a low detrussor leak-point pressure and good compliance. Recent spinal MRI is normal. A repeat
detrussor pressure of 41 cmH 2 O; the leakage was minimal. At capacity his pressure was 60 cmH 2 O with no reflux. His total capacity was 220 ml. The next step in his management should include:
(a) Bladder augment (b) Bilateral ureteral reimplants (c) Addition of an alpha-blocker (d) Bladder neck reconstruction
Answer: (a) It has been shown in several centers that in the myelodysplastic population, children with leak-point pressures of > 40 cmH 2 O are at greater risk for upper tract damage (hydronephrosis and reflux) than patients who have leak-point pressures < 40 cmH 2 O. (Page 759)
7. Rate of filling in urodynamic testing is determined by the bladder capacity. A medium fill rate is based on which percentage of bladder capacity:
(a) 2 % (b) 10 % (c) 15 % (d) 20 %
Answer: (d) Joseph 1 noted that a change in detrussor pressure, as well as maximum detrussor pressure, was adversely affected by increasing the rate of filling from slow (approximately 2 % ofestimatedbladder capacity, 0 – 10 ml/min) to medium fill (approximately 20 % of estimated bladder capacity, 10 – 100 ml/min).Ingeneral,itisrecommended to fill at < 10ml/mininchildren.(Page754)
8. Examinationofpressuresintheupper urinary tract can be performed using the Whittaker test. A normal unobstructed ureteral pressure is:
(a) < 5 cmH 2 O (b) < 10 cmH 2 O
(c) < 15 cmH 2 O (d) < 20 cmH 2 O
Answer: (c) (Table 51.3 Summary of the Whittaker Test, Page 762)
9. A 10-year-old male is referred regarding a painful perineum. If a postvoid bladder scan was performed prior to the evaluation, you would expected the patient ' s postvoid residual volume to be:
(a) Negligible (b) 20 % of bladder capacity (c) 25 % of bladder capacity (d) 35 % of bladder capacity
Answer: (d) Estimation of residual urine can be an important clue to overall bladder function. Except in infants, the child ' s bladder should empty to completion with each void. (Page 752)
10. A 5-year-old male is having urodynamic assessment for symptoms associated with a suspected tethered spinal cord. The cystometrogram (CMG) showed elevated detrussor pressures and multiple unstable bladder contractions at low volumes. The
with electromyography (EMG) leads in place. A 6F catheter was used along with a fill rate of 15 ml/min of normal saline. The abnormalities in the exam may be due to:
(a) Filling the bladder too slowly (b) The use of normal saline as opposed to
carbon dioxide gas (c) Vesicoureteral reflux (d) Filling the bladder too quickly
Answer: (d) It is not recommended to use carbon dioxide gas for filling. Joseph 1 noted that a change in detrussor pressure, as well as maximum detrussor pressure, was adversely affected by increasing the rate of filling from slow (approximately 2 % of estimated bladder capacity, 0 – 10 ml/min) to medium fill (approximately 20 % of estimated bladder capacity, 10 – 100 ml/min). In general, it is recommended to fill at < 10 ml/min in children. (Page 754)
