From Wikipedia, the free encyclopedia - View original article
|Classification and external resources|
|Classification and external resources|
Vesicoureteral reflux (VUR) is an abnormal movement of urine from the bladder into ureters or kidneys. Urine normally travels from the kidneys via the ureters to the bladder. In vesicoureteral reflux the direction of urine flow is reversed (retrograde).
Vesicoureteral reflux may present before birth as prenatal hydronephrosis, an abnormal widening of the ureter or with a urinary tract infection or acute pyelonephritis. Symptoms such as painful urination or renal colic/flank pain are not symptoms associated with vesicoureteral reflux.
Newborns may be lethargic with faltering growth, while infants and young children typically present with pyrexia, dysuria, frequent urination, malodorous urine and GIT symptoms, but only when urinary tract infection is present as the initial presentation of VUR.
In healthy individuals the ureters enter the urinary bladder obliquely and run submucosally for some distance. This, in addition to the ureter's muscular attachments, helps secure and support them posteriorly. Together these features produce a valvelike effect that occludes the ureteric opening during storage and voiding of urine. In people with VUR, failure of this mechanism occurs, with resultant retrograde flow of urine.
Insufficient submucosal length of the ureter relative to its diameter causes inadequacy of the valvular mechanism. This is precipitated by a congenital defect/lack of longitudinal muscle of the intravesical ureter resulting in an ureterovesicular junction (UVJ) anomaly.
In this category the valvular mechanism is intact and healthy to start with but becomes overwhelmed by raised vesicular pressures associated with obstruction, which distorts the ureterovesical junction. The obstructions may be anatomical or functional. Secondary VUR can be further divided into anatomical and functional groups as follows:
Anatomical: Posterior urethral valves; urethral or meatal stenosis.
These causes are treated surgically when possible.
Functional: Bladder instability, neurogenic bladder and non-neurogenic neurogenic bladder Urinary tract infections may cause reflux due to the elevated pressures associated with inflammation.
Resolution of functional VUR will usually occur if the precipitating cause is treated and resolved. Medical and/or surgical treatment may be indicated.
It has been estimated that VUR is present in more than 10% of the population. In children without urinary tract infections 17.2-18.5% have VUR, whereas in those with urinary tract infections the incidence may be as high as 70%.
Younger children are more prone to VUR because of the relative shortness of the submucosal ureters. This susceptibility decreases with age as the length of the ureters increases as the children grow. In children under the age of 1 year with a urinary tract infection, 70% will have VUR. This number decreases to 15% by the age of 12.
Although VUR is more common in males antenatally, in later life there is a definite female preponderance with 85% of cases being female.
The younger the age of the patient and the lower the grade at presentation the higher the chance of spontaneous resolution. Most (approx. 85%) of grade I & II cases of VUR will resolve spontaneously. Approximately 50% of grade III cases and a lower percentage of higher grades will also resolve spontaneously.
The following procedures may be used to diagnose VUR:
An abdominal ultrasound might suggest the presence of VUR if ureteral dilatation is present; however, in many circumstances of VUR of low to moderate severity, the sonogram may be completely normal, thus providing insufficient utility as a single diagnostic test in the evaluation of children suspected of having VUR, such as those presenting with prenatal hydronephrosis or urinary tract infection (UTI). VCUG is the method of choice for grading and initial workup, while RNC is preferred for subsequent evaluations as there is less exposure to radiation. A high index of suspicion should be attached to any case a where a child presents with a urinary tract infection, and anatomical causes should be excluded. A VCUG and abdominal ultrasound should be performed in these cases
Early diagnosis in children is crucial as studies have shown that the children with VUR who present with a UTI and associated acute pyelonephritis are more likely to develop permanent renal cortical scarring than those children without VUR, with an odds ratio of 2.8. Thus VUR not only increases the frequency of UTI's, but also the risk of damage to upper urinary structures.
The goal of treatment is to minimize infections, as it is infections that cause renal scarring and not the vesicoureteral reflux. Minimizing infections is primarily done by prophylactic antibiotics in newborns and infants who are not potty trained. However in children who are older, physicians and parents should focus on bowel and bladder management. Children who hold their bladder or who are constipated have a greater number of infections than children who void on a regular schedule. When medical management fails to prevent recurrent urinary tract infections, or if the kidneys show progressive renal scaring then surgical interventions may be necessary. Medical management is recommended in children with Grade I-III VUR as most cases will resolve spontaneously. A trial of medical treatment is indicated in patients with Grade IV VUR especially in younger patients or those with unilateral disease. Of the patients with Grade V VUR only infants are trialled on a medical approach before surgery is indicated, in older patients surgery is the only option.
Deflux is a gel that is used in endoscopic injections to treat Vesicoureteral Reflux. It is the material that the surgeon injects around the ureteral opening to create a valve function and stop urine from flowing back up the ureter. Deflux consists of two types of sugar-based molecules called dextranomer and hyaluronic acid. Both substances are well-known from previous uses in medicine. Both materials are also biocompatible, which means that they do not cause significant reactions within the body. In fact, hyaluronic acid is produced and found naturally within the body.
Medical treatment entails low dose antibiotic prophylaxis until resolution of VUR occurs. Antibiotics are administered nightly at half the normal therapeutic dose. The specific antibiotics used differ with the age of the patient and include:
After 2 months the following antibiotics are suitable:
Urine cultures are performed 3 monthly to exclude breakthrough infection. Annual radiological investigations are likewise indicated. Good perineal hygiene, and timed and double voiding are also important aspects of medical treatment. Bladder dysfunction is treated with the administration of anticholinergics.
A surgical approach is necessary in cases where a breakthrough infection results despite prophylaxis, or there is non-compliance with the prophylaxis. Similarly if the VUR is severe (Grade IV & V), there are pyelonephritic changes or congenital abnormalities. Other reasons necessitating surgical intervention are failure of renal growth, formation of new scars, renal deterioration and VUR in girls approaching puberty.
There are three types of surgical procedure available for the treatment of VUR: endoscopic (STING/HIT procedures); laparoscopic; and open procedures (Cohen procedure, Leadbetter-Politano procedure).
2010 guidelines from the American Urological Association recommend ongoing monitoring of children with VUR until the abnormality resolves or is no longer clinically significant. The recommendations are for annual evaluation of blood pressure, height, weight, urinalysis, and renal ultrasonography.