Pediatric Vesicoureteral Reflux Clinical Presentation

Most children with vesicoureteral reflux (VUR) present in 2 distinct groups.

• The first group presents with hydronephrosis, often prenatally identified using ultrasonography. These children typically progress through evaluation and treatment in the absence of clinical illness.
• The second group presents with clinical urinary tract infection (UTI). Even for experienced pediatricians, the diagnosis of UTI in children can be difficult.

  • Children often present with nonspecific signs and symptoms. Infection in infants can manifest as failure to thrive, with or without fever. Other features include vomiting, diarrhea, anorexia, and lethargy.
  • Older children may report voiding symptoms or abdominal pain.
  • Pyelonephritis in young children is more likely to manifest with vague abdominal discomfort rather than with the classic flank pain and tenderness observed in adults. The presence of fever, while highly suggestive of pyelonephritis, is not reliable enough to lead to the diagnosis.
  • Even today, children occasionally present with advanced reflux nephropathy, manifesting as headaches or congestive heart failure from untreated hypertension, or with uremic symptoms from renal failure.
  • A small group of children without evidence of UTI present with symptoms of sterile reflux, which can include flank or abdominal pain before or during voiding, as well as double voiding or incomplete emptying resulting from delayed drainage of urine out of the upper tracts.

As with the history, few findings on physical examination suggest vesicoureteral reflux or UTI.

• Fever, flank or abdominal tenderness, or an enlarged palpable kidney may be present;
• In the absence of reliable historical or physical findings, diagnosis depends on laboratory testing and imaging, as well as family history.

The cause of the defect in primary reflux is unknown.

• The existence of a strong genetic component is indicated by the high rate of reflux in relatives of patients with reflux, but the mechanism of transmission is not clear. Some investigators favor a polygenic mode of inheritance, whereas others have suggested autosomal or sex-linked transmission with variable penetrance.
• The possibility that UTI may cause reflux has also been investigated. Indeed, a subset of patients has been identified in whom reflux was detectable only during an episode of cystitis. However, most authorities think that UTI and reflux are independent variables and that rates of vesicoureteral reflux are higher in children with UTI because these children are actively screened for reflux. The cause-and-effect picture is even less clear in children with secondary reflux.
• Rates of reflux are likely increased in the setting of congenital bladder outlet obstruction and neurogenic bladder. More than 50% of boys with posterior urethral valves have vesicoureteral reflux. Similar results were seen in a series of children undergoing urodynamic studies for neurogenic bladder.
• Dysfunctional voiding, with its inherent increase in intravesical pressure, likely also results in reflux, even in otherwise healthy children. Uninhibited bladder contractions, often associated with contraction of the voluntarily controlled external urinary sphincter to prevent wetting, increase intravesical pressure. The combination of high-pressure voiding and vesicoureteral reflux increases the risk of pyelonephritis beyond that of the child with low-pressure reflux.
• Confounding all of these data is the fact that urodynamic studies on children are difficult to perform and evaluate; this is true especially with infants, in whom normal reference data are sparse. Whether vesicoureteral reflux observed in association with voiding dysfunction and obstruction is a direct result of that dysfunction or simply a component of a grossly abnormal urinary tract is not known.
• A unique and complex group of children presents with dysfunctional elimination, which consists of a symptom complex heralded by infection, severe constipation, and daytime wetting. Despite the primary urinary tract presentation, the primary focus should be in the management of constipation and bowel habits. A subset of these children have infrequent voiding and incomplete bladder emptying, which further increases the likelihood of UTI.