Pediatric-Kidney & Ureter-Reflux & Megaureter - 117

Front 1

What is vesicoureteral reflux? Is VUR deleterious in inself?

Back 1

*VUR represents the retrograde flow of urine from the bladder into the upper urinary tract.

*No, reflux in itself that is without bacterial contamination and low in pressure has not been documented to be injurious. However, reflux in the presence of bacteria is a risk factor for upper urinary tract infection or pyelonephritis, as it accelerates bacteriuria by delivering infected urine to the renal pelvis.

-Sterile urine is benign, which is the basis of current medical management to maintain urine sterility until reflux resolves.

Front 2

What triad of clinical findings constitutes reflux nephropathy?

Back 2

-renal scarring

-hypertension

-VUR

Front 3

In discussing the epidemiology of VUR, what demographic factors affect prevalence and in what way?

Back 3

i. Age- prevalence of reflux correlates inversely with the age of the study population. With linear growth, spontaneous resolution of reflux occurs in many patients.

ii. Race- VUR is more commonly a disease of fair-skinned individuals. Prevalence is significantly lower among AA children and children of Mediterranean origin. Several studies have shown a relative 10-fold lower frequency of reflux in female children of african descent, with resolution of VUR sooner in this population as well. Hispanic and Caucasian children have an almost equal incidence.

iii. Sibling predisposition- siblings of patients with known reflux have approximately a 30% prevalence of reflux, with younger siblings being at greatest risk.

iv. Gender- difficult to assess because of the epidemiology of UTIs in children, as boys and girls may present with reflux at different ages. Because UTIs are more common in uncircumcised boys than girls during the neonatal period, many boys are diagnosed with VUR as neonates. However, after the first year of life, the incidence of UTIs is much higher among girls than boys. Therefore, most school-aged children diagnosed with reflux are girls.

Front 4

With what genitourinary anomalies has VUR been shown to occur?

Back 4

i. Posterior urethral valves-congenital bladder outlet obstruction has been associated with reflux in up to 50% of patients.

ii. duplicated collecting system-reflux is commonly associated with the lower pole moiety of a duplicated system (Weigert-Meyer)

iii. Prune-Belly syndrome

iv. UPJ obstruction

v. bladder (paraureteral diverticula)

vi. MCDK/Renal agenesis

vii. Megacystis-Megaureter association

Front 5

What is the traditional classification system for defining reflux? How may the typical patient present?

Back 5

-PRIMARY reflux: results from a congenital deficiency in the formation of the UVJ, in the absence of any other predisposing pathology.

- these patients reflux despite an adequately low-pressure urine storage profile in the bladder. May have a laterally ectopic ureteral orifice consistent with a deficient submucosal ureteral tunnel, or low ureteral tunnel length-diameter ratio. Lack of submucosal or intramural ureteral length prevents the terminal ureter from closing like a flap valve when the bladder fills.

- these patients are the vast majority represented in clinic, otherwise healthy children who present with symptomatic UTIs.

-SECONDARY reflux: occurs as a result of other urinary tract dysfunction, which leads to a decompensation of a normally formed UVJ. Successful treatment of these patients depends on identification of the underlying etiologies, such as:

i. Neurogenic bladder:

-myelomeningocele/spina bifida: look for classic PE findings such as sacral dimple, hairy patch, gluteal cleft abnormalities, diminished rectal tone

-spinal cord injury: ask about constipation

ii. Obstruction:

-voiding dysfunction: uninhibited bladder contractions, early attempts to suppress bladder contractions during incomplete emptying

-PUV: note that reflux is present in 48-70% of patients with PUVs.

-ectopic ureteroceles, prolapsing ureteroceles into the bladder neck in females.

iii. Infection: cystitis may also predispose an otherwise marginally competent UVJ to demonstrate reflux.

Front 6

T/F: Ditropan cures VUR.

Back 6

True, in some cases. In older girls with uninhibited bladder contractions, a study showed that ditropan can eliminate reflux in up to 80% of refluxing ureters

Front 7

Describe the grading system of VUR, based on radiographic contrast images generated by VCUG.

Back 7

Grade I: Into nondilated ureter

Grade II: Into pelvis and calyces without dilatation

Grade III: Mild to mod. dilation of ureter, renal pelvis, calyces with minimal blunting of fornices

Grade IV: Moderate ureteral tortuosity and dilation of pelvis and calyces

Grade V: Gross dilation of ureter, pelvis, calcyes with loss of papillary impressions and ureteral tortuosity

Front 8

Which children should be evaluated for VUR?

Back 8

Children < 5yo

All children with a febrile confirmed UTI

Any male with UTI regardless of age or fever unless sexually active

Front 9

What are the two gold standards for detecting reflux in children and what are the advantages and disadvantages of each?

Back 9

VCUG and radionuclide cystogram (RNC). VCUG is better to show anatomic detail (such as PUV, bladder trabeculation. RNC exposes the child to only 1% of the radiation from a VCUG. However, it is unreliable for Grade I VUR as the overlay of the bladder obscures.

Front 10

Due to a scheduling snafu, you are called by Doris in the Peds Urology clinic to come evaluate a child for possible reflux, even though Dr. Sutherland is out of the country. He has a documented urinary tract infection, is febrile, and mom is asking whether he should have a VCUG study today. You are not sure and decide to call Dr. Sutherland, who takes your call while sunbathing in his speedos off the warm waters of Pompeii. What is his answer to you?

Back 10

-Never call me again, that's why I have a Peds Chief. No to the VCUG-though the study should occur at 1-2 weeks following the acute episode.

-the likelihood of detecting reflux is highest if the child is evaluated soon after the infection. It is believed that the presence of recent infection in the bladder predisposes a marginally competent UVJ to reflux, which may be missed if the delay to VCUG is long.

Front 11

What other studies may be helpful in the diagnosis and management of reflux? How?

Back 11

i. Urodynamics- many children with reflux have voiding dysfunction. The diagnosis is often suspected by a history of incontinence, frequency or urgency. Appropriate management of the voiding dysfunction often results in resolution of the reflux.

ii. Renal ultrasound- useful as an adjunctive technique in the grading of hydronephrosis and as a baseline for follow-up studies to monitor renal growth. Other important details on U/S include the degree of corticomedullary differentiation or increase in echogenicity of the kidney.

iii. Nuclear medicine renal scan (DMSA) and SPECT study: useful in the detection of renal cortical scars, sequelae of repeated infections. DMSA which is a radiotracer that is taken up by renal tubules and is indicate of glomerular filtration. SPECT is a 3-D reconstruction which only slightly increases the sensitivity of the DMSA (which is already 98%)- does not add much to your management strategy

Front 12

What is the best initial therapy for a 4-year old girl with newly identified grade II left VUR?

Back 12

Because low and moderate grade reflux (I-III) has a good chance for spontaneous resolution, antibiotic prophlaxis and observation is the best initial therapy for this child. Approximately 80% of patients with low-grade reflux will have spontaneous resolution, and more than 50% of patients with grade III reflux will have resolution. Grade IV reflux has a 10% chance of resolution, and grade V reflux rarely resolves spontaneously.

Front 13

List three strong indications for considering surgical correction in a child with low-grade VUR?

Back 13

-breakthrough infections or persistently positive urine cultures indicate that antibiotic prophylaxis is not working and surgical correction should be considered.

-non-compliance with medical therapy

-anatomic issues such as a periureteral diverticulum or grade V reflux, due to the low likelihood of spontaneous resolution.

Front 14

You are in Dr. Sutherland’s clinic seeing a new patient with recurrent febrile UTIs who had a VCUG today. It shows Grade IV VUR but also, the delayed post void films show retained contrast in the kidney. What do you think is going on and how will you go about fixing this?

Back 14

The patient has reflux but also possible concomitant UPJ obstruction. After confirming the presence of UPJ obstruction with lasix scan, you would want to fix the UPJ obstruction first and then later fix the UVJ so as to avoid further obstruction which may ensue if resistance added to UVJ when reflux is corrected. VUR is present in 9-18% of those with UPJ obstruction.

Front 15

What are the three radiologic signs of concomitant UPJ obstruction and VUR?

Back 15

Pelvis shows little or no filling but ureter is dilated suggesting kinking from reflux.

Contrast that does enter the pelvis is poorly visualized because of dilution in large pelvic volume

Large pelvis fails to exhibit proper drainage but retains contrast

Front 16

How can ultrasound RI values be helpful to you in suspecting reflux or infection?

Back 16

Increased RIs are often associated with high grades of VUR as well as in cases of upper tract UTI (versus lower tract)

Front 17

You have a patient you are following with Grade III VUR and recurrent UTIs who is on prophylactic antibiotics. She returns today with a follow-up renal ultrasound. What three findings on renal ultrasound will make you suspicious of renal impairment?

Back 17

Decrease in corticomedullary differentiation

Hyperechogenicity of the kidney

Absence of interval renal growth

Front 18

You are consulted in the NICU for a child with a renal ultrasound showing renal agenesis. What is the next diagnostic test you will order and why?

Back 18

VCUG to check for contralateral VUR because it is associated with this in 46% of cases.

Front 19

What indicators will assist you in informing parents of the likelihood of their child’s VUR resolution? What age will you quote at time of resolution and why?

Back 19

Lower grade VUR (Grades I and II) are more likely to resolve. Also, more likely to resolve at a younger age. Most resolve by age 5 because this is the time it takes for the UVJ to fully mature. Grade III reflux will resolve in approximately 50% of cases, higher grades (bilateral III, grade IV and V) less likely.

Front 20

You have a patient who you have placed on prophylactic antibiotics for VUR who returns to your clinic. The mother tells you that his pediatrician had drawn a CBC showing leukopenia and she is concerned. What is your first thought?

Back 20

The patient could be on TMP/SMX which can cause a transient leukopenia. You should discontinue the drug and it should resolve on its own.

Front 21

What is the first-line treatment for VUR?

Back 21

Prophylactic antibiotics nightly (amoxicillin is choice in <2mo and TMP/SMX is choice in >2mo). Macrobid is another option.

Front 22

What is one way to interpret breakthrough infections based on sensitivities?

Back 22

If sensitive to prophylactic antibiotic, then most likely dose is too low or patient is noncompliant. If resistant, then dose is too high or bladder is too full for too long

Front 23

Name the 6 principles common to surgical reflux correction.

Back 23

Exclusion of causes of secondary VUR

Adequate mobilization of distal ureter without tension or damage to blood supply

Creation of submucosal tunnel generous in caliber with 5:1 length:width ratio

Attention to entry point of ureter into bladder, direction of submucosal tunnel, and ureteromucosal anastomosis to prevent stenosis, angulation or twisting of ureter

Attention to muscular backing of ureter to achieve effective antireflux mechanism

Gentle handling of bladder to reduce postop hematuria and bladder spasms

Front 24

Which reimplantation procedure is the most commonly performed and why? What are its drawbacks?

Back 24

Cohen cross-trigonal because it is considered the easiest to perform and is also best for small and trabeculated bladders and also overcomes the problem of tunnel length. Drawbacks include problems in the future with retrograde access for stone procedures and stent placement.

Front 25

After performing a Politano-Leadbetter reimplantation on a child 2 weeks ago, a pediatrician calls you with the report of moderate hydronephrosis on a renal ultrasound that he ordered. Should you immediately call the patient into clinic?

Back 25

No- if the patient is asymptomatic, it is not uncommon to see mild hydro up to even 2-3 months after surgery secondary to inflammation

Front 26

How does the Politano-Leadbetter and Paquin techniques differ?

Back 26

Politano-Leadbetter is exclusively intravesical while Paquin is a combined intra and extravesical approach

Front 27

What is the main advantage of performing an extravesical approach reimplantation? What is a common complication from performing this procedure and does it resolve?

Back 27

Main advantage is minimal to no hematuria and decreased bladder spasms postoperatively. However, a common complication is postoperative transient voiding inefficiency in about 20%. Boys < 2yo with high-grade bilateral VUR are at highest risk. Most resolve within 2 weeks with foley catheter left in place.

Front 28

What is the "high reimplant" phenomenon?

Back 28

Angulation of the ureter occurs at the point of entry into the new hiatus secondary to a hiatus that was positioned too far laterally and anteriorly such that when the bladder fills the ureter is carried laterally and anteriorly resulting in difficulty draining when the bladder is full.

Front 29

What procedure may effectively manage VUR before surgical option is entertained? How does it work and is follow-up imaging recommended?

Back 29

Deflux, which has achieved high success rates in lower grade VUR. Deflux substance seems to recreate the natural intravesical tunnel between the ureter and bladder. Upper tract imaging with an U/S 4-6 weeks after the procedure is prudent.

Front 30

What are the four main categories of megaureter? If you see megaureter on ultrasound in a newborn infant, which type is most likely? (see Figure 117-23, p. 3468)

Back 30

*Obstructive,
*Refluxing,
*Non-obstructive, non-refluxing (most likely in infant)
*Obstructive & refluxing.

*Each category is then divided into primary and secondary etiology.

Front 31

How should megaureter be evaluated?

Back 31

Start with renal ultrasound, then VCUG to see if reflux is present. Also, obtain a lasix renal scan to assess function and obstruction.

Front 32

How should primary nonrefluxing megaureter be treated?

Back 32

Watchful waiting if no symptoms or UTI. If hydroureteronephrosis is severe and recurrent UTIs with documented decrease in renal function, consider surgery

Front 33

If you have an infant with severe hydroureteronephrosis as well as worsening renal function, what should you do?

Back 33

After obtaining your studies (including renal ultrasound and VCUG) to confirm the absence of a correctable cause such as PUV, take the baby to the OR for a cutaneous ureterostomy to temporize them until they are old enough for a reimplantation procedure.

Front 34

What are two ways to manage the severe dilation of MGU when attempting a reimplantation procedure?

Back 34

Plication or infolding (if moderately enlarged ureter) whereas excisional tapering is useful for thick and/or severely dilated ureters. Be sure to leave a stent in place for 5-7 days.

Front 35

What is the Politano Leadbetter technique for ureteral re-implantation?

Back 35

Politano-Leadbetter technique. A, Typical approach to the bladder for reimplantation. A transverse, lower abdominal incision is made along a skin crease one or two fingerbreadths above the symphysis pubis. B, Fine sutures are placed above and below the ureteral orifice for handling. A feeding tube in the ureter aids in the initial dissection. C, A needle-tip cautery outlines a circumferential incision around the orifice. D, Tenotomy scissors initially establish the plane of dissection inferiorly, where ureteral damage can be avoided. The plane is then carried around the ureter. E, With the aid of a lighted suction tip and two Senn retractors, a fine gauze dissector is used to sweep the peritoneum from the posterior bladder wall. F, After sweeping the peritoneum away, a blunt right-angle clamp indents the bladder from behind at a new hiatus approximately 2.5 cm superior and somewhat medial to the original hiatus. G, The clamp is incised upon from within and generously spread to make certain that the new hiatus is wide enough. H, A second right-angle clamp follows the first from within the bladder to the original hiatus. I, The right-angle clamp grasps the stay suture, and the ureter is pulled through the new hiatus. J, The inferior lip of muscle at the new hiatus is divided for a few millimeters to eliminate any ureteral angulation at its entrance to the submucosal tunnel that is created with scissors. K, The ureter is brought through the new tunnel to the original hiatus. L, The ureter is anastomosed to the original hiatus in the classic Politano-Leadbetter technique. Proximal mucosa can be closed over the ureter to give the tunnel additional length. M, Ureteral advancement is also helpful, especially if the original hiatus is laterally positioned. A second submucosal tunnel can be created toward the bladder neck to place the new orifice in a more inferior position and gain additional length for the reimplant

Front 36

What is the Paquin technique for ureteral re-implantation?

Back 36

Paquin described a combined extravesical/intravesical technique in 1959. The new ureteral hiatus is created from outside the bladder, thus avoiding the difficulties associated with this maneuver in the Politano-Leadbetter technique. As with most of the other open techniques, a success rate of greater than 95% for primary VUR is achieved with this method.

The ureter in the Paquin technique can be approached extravesically (see the later section “Extravesical Procedures”) before opening the bladder. A right-angle clamp is applied at the UVJ, the ureter is divided, and a 3-0 polyglactin suture is used to suture-ligate the original hiatus. The bladder is then opened in the midline, and a new hiatus located cephalad to the previous position is created. The peritoneum is carefully cleared off the back wall of the bladder at the site of the new hiatus. A right-angle clamp is passed from inside the bladder under direct vision, and one end of a 5-mm Penrose drain is pulled into the bladder. A mosquito snap applied to the Penrose drain acts as a holder and facilitates creation of the submucosal tunnel. The mucosa is dissected off the detrusor circumferentially at the new hiatus. The length of the submucosal tunnel is governed by the diameter of the ureter, and a 5:1 ratio is usually achievable. In more complex cases, a psoas hitch may be required to achieve longer tunnel length. The tunnel is developed by carefully lifting the mucosa off the detrusor with tenotomy scissors. Countertraction on the mucosa is helpful, especially in redo cases and when the bladder wall is trabeculated. Once the tunnel is developed, the remainder of the reimplant operation is similar to the Politano-Leadbetter procedure.

Front 37

What is the Glenn-Anderson technique for ureteral re-implantation?

Back 37

In 1967 Glenn and Anderson described their technique of ureteral reimplantation ( Fig. 117-16 ). By using the same hiatus and advancing the ureter distally toward the bladder neck, the potential complications associated with the Politano-Leadbetter technique are avoided, specifically, kinking of the ureter. The ureter is mobilized as described earlier. A submucosal tunnel is created toward the bladder neck with tenotomy scissors. The distance from the hiatus to the bladder neck limits the length of the tunnel. Glenn and Anderson (1978) later described a modification that allows creation of a longer tunnel by incising the detrusor proximally at the original hiatus. The detrusor edges are then reapproximated distal to the ureter. With advancement of the ureter toward the bladder neck, the distal anastomosis of the ureter could be challenging with this technique. As with the other procedures, the results with this technique are excellent, with a 98% success rate

Front 38

What is the Glenn Anderson technique for ureteral re-implantation?

Back 38

In 1967 Glenn and Anderson described their technique of ureteral reimplantation ( Fig. 117-16 ). By using the same hiatus and advancing the ureter distally toward the bladder neck, the potential complications associated with the Politano-Leadbetter technique are avoided, specifically, kinking of the ureter. The ureter is mobilized as described earlier. A submucosal tunnel is created toward the bladder neck with tenotomy scissors. The distance from the hiatus to the bladder neck limits the length of the tunnel. Glenn and Anderson (1978) later described a modification that allows creation of a longer tunnel by incising the detrusor proximally at the original hiatus. The detrusor edges are then reapproximated distal to the ureter. With advancement of the ureter toward the bladder neck, the distal anastomosis of the ureter could be challenging with this technique. As with the other procedures, the results with this technique are excellent, with a 98% success rate

Front 39

What is a cohen cross-trigonal re-implantation?

Back 39

Cohen's technique, which was described in 1975, overcomes the limitation of tunnel length in the Glenn-Anderson technique by directing the tunnel across the trigone toward the contralateral bladder wall (Figs. 117-17 and 117-18 [17] [18]). The difficulty with the distal anastomosis in the Glenn-Anderson technique is also eliminated.

Front 40

How does one perform a bilateral Cohen cross trigonal ureteral reimplantation?

Back 40

Front 41

What are trade names for nitrofurantoin?

Back 41

*Macrobid, Macrodantin, Furadantin