School of Medicine, Wake Forest University Baptist Medical Center, Winston Salem, NC 27157, USA
We present a retrospective review of the scientific and clinical advances, extending over four decades, which have linked vesicoureteral reflux, with renal injury, and urinary tract infection. We have traced the original studies, coupled with advances in technology which led to the awareness, and ability to detect and diagnose the problems early in childhood. These advances progressed through clinical studies which defined the epidemiology of both reflux and urinary tract infection. Along with these diagnostic advances, there were numerous surgical developments, which allowed progressive improvements in the outcomes and effectiveness of a variety of treatment modalities. All of this literature leads us to the current era, when several clinical trials are currently underway in an effort to more fully define the most efficacious and safe methods to treat vesicoureteral reflux and associated urinary tract infection.
Vesicoureteral reflux may have been the major catalyst
for the development of the subspecialty of pediatric urology, now approaching a
milestone in North America, with the
soon-to-be awarding of a certificate of special competence. How did this happen?
In the first textbook of Urology in
Childhood, 1974, Dr. Innes Williams included a chapter on reflux, in which his
opening sentence states “the problem of reflux has occasioned more controversy
than any other topic in pediatric urology” [1]. I submit in writing this article the view
that this situation has changed very
little to this day, more than 30 years later.
Reflux was recognized very early, as
an abnormal function of the ureterovesical junction, but it was Hutch who
recognized it in association with neurogenic bladder, in the spinal injured
patients, and who linked the reflux to the renal injury in those patients [2]. Reflux was subsequently demonstrated in some
pediatric patients with UTI, but there
were several studies which showed that reflux was not present in normal
infants. These data were brought forward because of the ready availability of
voiding cystourethrography—we now assume that these studies are routine and
customary—whereas in 1960s and 1970s they were neither
available technically, nor did many imagers have any of the facilities or
skills that are now standard of care throughout the world.
The next milestone was the
recognition that vesicoureteral reflux was associated with urinary tract
infections, but also that it occurred as a primary defect in children. Prior principles had shown reflux to be
associated with other congenital anomalies or defects such as neurogenic
bladder. Hodson and Edwards [3]
described a relationship between urinary tract infections and reflux, and
further investigators demonstrated this to be present in a significant number
of children with recurrent pyelonephritis [4].
These findings led physicians and
surgeons to recognize the importance of UTI as a cause of both pyelonephritis
and as an extension of this to recognize relationship between chronic scarring
and end-stage renal disease, and UTI with reflux. Kunin (1970) published data showing the
prevalence of UTI in school-age children. The scene was set for the imposition
of two forms of therapy which emerged as the
science of the day—antibiotics for gram negative bacterial
infections, and surgery for vesicoureteral reflux.
The
1970s witnessed the emergence of
antibiotics, including aminioglycosides, chloramphenicol, and cephalosporins,
which proved effective in the treatment of sepsis and pyelonephritis caused by
gram negative organisms. Although one of
these proved myelotoxic and was removed from use, the others continued to be
employed more frequently, and further refinements both improved their efficacy
and reduced their toxicity. Along with
the readily available treatment modalities, the recognition of UTI as an
important cause of sepsis in the neonate and young infant became a more common
diagnosis. In this era, the
differential diagnosis fever in an infant included meningitis which was much
more common as a cause of fever and sepsis in infants' than is now the case. Thus, the subsequent
investigation of UTI, with personnel and equipment to carry out effective
cystograms, led to the diagnosis of vesicoureteral reflux in increasing
numbers. Parallel with the growing
frequency of the diagnosis of reflux was a growing experience and expertise in
the surgery of reflux. Politano and Leadbetter [5] described an effective operative procedure which could achieve
successful treatment with relatively minimal morbidity—this became
widely utilized in North America, while the Lich Gregoir extravesical techniques [6] were
more widely used in Europe. Following upon these successes, Paquin [7], Glenn and Anderson [8], and
finally Cohen [9] improvements and
modifications of ureteroneocystostomy are resulting in their wide utilization throughout the world in 1980s. The AAP section
of urology was started in this period, and the specialty of pediatric urology
emerged as a recognized specialty, dedicated to the treatment of children with congenital
defects of the genitourinary system.
Dr.
John Duckett and a dedicated group of colleagues bridged the gap between pediatric
urologists and pediatric nephrologists, in both Europe and North
America, to formulate a prospective study to test the hypothesis
of the best treatment for vesicoureteral reflux. The international reflux study
was born and completed, with publications in 1992, which answered some questions,
but left many more unanswered. It was apparent that surgical correction of
reflux was feasible, safe, although inconsistent in the complication rates at
varying centers. Similarly, it was
apparent that reflux would resolve spontaneously. Thus, the most optimal treatment was
uncertain. The outcomes measured were
primarily renal scarring, but other features of the “disease” became more
confusing—was the renal
scarring pre-existent, or solely the result of the reflux, or of the UTI?
Although dysfunctional voiding was an exclusion factor, the study
concluded that 15% of children did have dysfunctional voiding. Was this now to play a part in the treatment
of the recurring UTIs? Was the reflux
actually a factor in the UTIs, since even after the correction of reflux,
persistence of UTIs occurred? Many
questions were answered, but many more remained.
In
this era of excitement and involvement in the international reflux study, a new
player emerged as O’Donnell and Puri [10] published data in 1984, showing that
the cystoscopic injection of Teflon paste into the subureteric space could
result in the resolution of vesicoureteral reflux. Following the rapid
popularization of this technique, mainly in Europe, it was disclosed by
researchers in USA [11] that Teflon could potentially be absorbed, and migrate to other areas of
the body, including the brain and lymphatics. These data, combined with
speculation and fear that leaked Teflon, leaked from prosthetic implants could be a potential
cause of autoimmune disease, led the Federal authorities in USA to
insure that the subureteric injection of
Teflon would not be approved in North America.
Nonetheless, a new debate had been born,
centered on the child with UTI and vesicoureteral reflux. At meetings, becoming more populated with
well trained and proficient pediatric urologists from around the world, debates
became heated, stimulating, and amusing. Three of our greatest leaders, each a
proponent of either open surgical correction, observational treatment alone or
subureteric injection (Duckett, Ransley, O’Donnell), led the assemblies in ever
increasing circles of confusion and varied convictions.
Two new pieces of data were added to
the continuing puzzle; the emergence of
antenatal ultrasound, which showed hydronephrosis in up to 1% of fetuses, and
the publication by Noe [12], that vesicoureteral reflux could be shown in up to
25% of siblings who were diagnosed with reflux. The groups of children with
reflux diagnosed on the basis of either
antenatal hydronephrosis and subsequently diagnosed reflux (20% of those with
hydronephrosis), and also those diagnosed on the basis of sibling screening led
to an ever increasing population of children with reflux.
Perhaps
the latest piece of the technology puzzle,
was added by Läckgren et al., who
published data on a newer substance, dextranomer/hyaluronic acid copolymer
(Dx/HA) [13], which unlike other alternates to Teflon, proved to be durable,
effective, and safe. It was approved for
use in the USA and Canada
and is
now widely utilized around the world.
Antibiotic
prophylaxis, the nonsurgical treatment modality used throughout all these decades
as an alternate to surgical therapy, has now also come into dispute. The
emergence of resistant strains of gram negative bacteria is growing, and
possibly based on the widespread generic use of many antibiotics, a global
increase in methicillin resistant staph aureus (MRSA) is posing serious
challenges to treatment of infants with sepsis.
A
new multicenter trial is now opened for recruitment in the United States and Canada (RIVUR),
funded by the NIDDK, which will randomize children, presenting with UTI, and
reflux between treatment with prophylactic antibiotics, and with observation
alone [14]. The primary end point is the
recurrence of UTI, with secondary end point being the development of renal
scar. A similar study is ongoing in France.
We
have come full circle, starting with a new diagnosis—reflux,
previously unrecognized, which was assumed to be a cause of recurrent uti, and
renal scarring, through three decades of
evolving developments in technology and science showing a myriad of ways in
which we could cure the reflux. Over 25 years ago, Dr. JR Woodard, a world
leader of the time, stated “As one looks back over the last 30 years of reflux
history, it is ironic that urologists have become so expert at its surgical
correction before understanding much about its natural history and true
clinical significance” [15]. We now dwell in a world where we STILL question whether
the reflux itself is the major problem, or just an easily diagnosed and treated
cofactor. Hopefully, the rigors of
current science, based on prospective and randomized data, will answer some of
these ongoing questions and allow us to treat the children, whom we treat, with
the best, safest, most cost-effective, and noninvasive methodologies available
to achieve our health-related aims. I believe these aims continue to be the
effective treatment and prevention of UTI and the prevention of renal injury.