Chap137 VUR

Main reason for reflux is a fundamental deficiency in the function of the UVJ antireflux mechanism while remaining factors (bladder and ureter) remain normal or relatively noncontributory.

Reflux caused by overwhelming the normal function of the UVJ. Bladder dysfunction of a congenital,acquired, or behavioral nature is often the root cause of secondary reflux.

Thus it is apparent that primary and secondary reflux may not always be mutually exclusive or that what is perceived as primary reflux in some children may, in fact, be secondary to abnormal voiding patterns.

Reflux nephropathy

• Diagnosis
• Both an abnormal urinalysis result and a positive urine culture result are needed to confirm inflammation
• A positive culture result is defined as at least 50,000 colony-forming units per milliliter, rather than the previous criterion of at least 100,000 colony-forming units per milliliter
• Guidance is added for using clinical criteria to establish a threshold to decide whether to obtain a urine specimen

• Treatment
• Oral treatment is as effective as parenteral treatment

• Imaging
• Voiding cystourethrography is not recommended routinely after the first febrile urinary tract infection;ultrasonography should include the bladder and kidneys.

• Follow-up
• Emphasis is on urine testing with subsequent febrile illnesses, rather than on regularly repeated urine cultures after treatment.

• - UTI in children younger than 5 years old
• - All children with a febrile UTI, and
• - Male with a UTI regardless of age or fever, unless sexually active

 More recent guidelines specifically for children under 2 years of age from the American Academy of Pediatrics (AAP) tighten the recommendation for voiding cystography to follow a second rather than the initial febrile UTI, with infection based on stricter culture criteria.

Obstruction usually occurs in the caudo zone, and ureters positioned in the cranio zone are likely to result in reflux. Ureters positioned in the normal (N) zone are associated with normal kidneys. Because of ureteral bud abnormality, renal dysplasia occurs with ureters projecting from both abnormal positions.

proposeda “Big Bang” theory for the origin of scars followinginfant pyelonephritis. They observed that most ofthe scarring to which the kidney is ultimately susceptibleoccurs after the initial bout of pyelonephritis andthat further scarring in the absence of repeated pyelonephriticepisodes is unlikely to occur

• A convex papilla (right) does not reflux because the crescentic or slit like openings of its collecting ducts open obliquely onto the papilla.
• In contrast, a concave (left) or flat papilla refluxes because its collecting ducts open at right angles onto a flat papilla.

The greatest risk for postinfection renal scarring is in the first year of life.

UPJ should be repaired first.

A concomitant reimplantation and dismembered pyeloplasty should be discouraged, as the ureteral blood supply may be compromised.

Walker (1994) summarized the essential tenants of reflux management as follows:

• 1. Spontaneous resolution of reflux is very common.
• 2. High-grade reflux is less likely to resolve spontaneously.
• 3. Sterile reflux is benign.
• 4. Extended use of prophylactic antibiotics is benign.
• 5. Success of (open) surgical correction is very high.

Maintaining urinary sterility through the judicious use of single daily low-dose antimicrobial prophylaxis.

Nighttime dosing allows for antibiotic concentration in the bladder urine over the longest period of expected physiologic retention,when infection is most likely to develop.

• Children younger than 2 months of age possess relative hepatic immaturity and are unable to clear sulfamethoxazole efficiently;the drug displaces fetal bilirubin and leads to jaundice.
• After 2 months of age, the antibiotic of choice becomes trimethoprim-sulfamethoxazole

1. If the organism is sensitive to the prescribed prophylactic antibiotic, the child or parent has likely not been compliant or the dose is too low,

2.If the organism is resistant to the prescribed antibiotic,either the residual bladder volume is too high too often or the dose is too high

• - Exclusion of causes of secondary VUR
• - Adequate mobilization of the distal ureter without tension or damage to its delicate blood supply
• - Creation of a submucosal tunnel that is generous in caliber and satisfies the 5 : 1 ratio of length to width recommended by Paquin (1959)
• - Attention to the entry point of the ureter into the bladder(hiatus), the direction of the submucosal tunnel and the ureteromucosal anastomosis to prevent stenosis, angulation,or twisting of the ureter
• - Attention to the muscular backing of the ureter to achieve an effective antireflux mechanism
• - Gentle handling of the bladder to reduce postoperative hematuria and bladder spasms

• The surgical procedures can be classified on the basis of the approach to the ureter as intravesical, extravesical or combined.
• Furthermore, they can be classified on the basis of the position ofthe submucosal tunnel in relation to the original hiatus intosuprahiatal or infrahiatal.

• Suprahiatal Tunnels
• - Politano-Leadbetter Technique
• - Paquin Technique - combined extravesical/intravesical technique

• Infrahiatal Tunnels
• - Glenn-Anderson Technique
• - Cohen Cross-Trigonal Technique - well suited for small bladders and thick-walled bladders

?

• Nonautologous Materials
• Polytetrafluoroethylene (PTFE)
• Cross-linked bovine collagen
• Polydimethylsiloxane
• Dextranomer hyaluronic copolymer (Deflux)
• Coaptite

• Autologous Materials
• Chondrocytes
• Fat
• Collagen
• Muscle

Gil-Vernet Procedure

Both ureters should have a common sheath reimplantation because the paired ureters typically share blood supply along their adjoining wall, and mobilization as one unit with a “common sheath” preserves vascularity and minimizes trauma.

10% to 15%. 

Prophylactic bilateral reimplantation for unilateral reflux is not indicated.

• BP in VUR patients
• Genital examination - child denied

D/D for VUR - Megaureter, PUV, stones, ureterocele, all congenital abnormalities, dysfunctional voiding 

History in child - bladder palpable or not, dribbling or not, nocturnal eneuresis,

• Lump
• That dissappears after passage of large amount of urine 
• Dietels crisis - pain, distension followed by passage of large amount of urine, after that pain and distension resolves

• Randomized Intervention for the Management of Vesicoureteral Reflux.
• RIVUR is a National Institutes of Health multicenter, double-blind, randomized, placebo-controlled trial designed to evaluate the effectiveness of antimicrobial prophylaxis in children found to have reflux after an initial UTI. Fifteen collaborating centers enrolled approximately 600 children with grade 1 to 4 reflux after an initial or second febrile or symptomatic UTI. Study participants were randomized to oral placebo versus oral TMP-SMX antibiotic prophylaxis. The primary outcome measure was the development of recurrent febrile or symptomatic UTI.
• Results suggested that antibiotic prophylaxis reduced recurrent UTI risk by 50% (39 of 302 antibiotic vs. 72 of 305 prophylaxis subjects), particularly in subjects with febrile UTI or bowel/bladder dysfunction at baseline. However, renal scarring findings appeared unaffected by prophylaxis (11.9% vs. 10.2% in antibiotic vs. prophylaxis groups, respectively).

• Retrovesical ureteric diameter (RVUD) - if >7mm, that is megaureter. 
• Along with it, if kidney is dilated, then the term comes the hydroureteronephrosis

Megacystis megaureter ? - after long VUR, bladder starts to dilate 

High residual volume is because of secondary VUR, if patient is asked to void, all urine goes to ureter, and when patient comes again for USG, there all urine from ureter comes to bladder - high PVRU

If high residual volume, ask to void 2-3 times, then only see PVRU

Bladder capacity - 7 * weight in KG