Long-term DxHA implants may create diagnostic dilemma

May 18, 2008

Young children who present with calcifications in the ureter on computed tomography scans may not have ureteral stones, but may simply have a history of receiving dextranomer/hyaluronic acid copolymer (Dx/HA [Deflux]) injections for the treatment of vesicoureteral reflux, according to pediatric urologists from Emory University in Atlanta. Their study findings were presented as a word of caution to radiologists and emergency room physicians who may suspect stones in children with abdominal pain and associated imaging findings.

Young children who present with calcifications in the ureter on computed tomography scans may not have ureteral stones, butmay simply have a history of receiving dextranomer/hyaluronic acid copolymer (Dx/HA [Deflux]) injections for the treatment ofvesicoureteral reflux, according to pediatric urologists from Emory University in Atlanta. Their study findings were presentedas a word of caution to radiologists and emergency room physicians who may suspect stones in children with abdominal pain andassociated imaging findings.

However, distinguishing a stone from a DxHA implant can be based on simple imaging and clinical characteristics that will helpclinicians avoid a misdiagnosis, the researchers said at the AUA annual meeting here.

"The knee-jerk reaction now in emergency rooms is, abdominal pain equals a CT scan," said lead author Andrew Kirsch, MD. "[ERphysicians] started to pick up what appeared to be calcifications or densities in the ureter, and they were misdiagnosed asureteral stones. We know of several of cases around the country where these children underwent intervention to treat thesestones.

"Now, with this information, unnecessary intervention can be avoided."

The Emory database of nearly DxHA 900 patients was investigated to determine how many patients had undergone postoperativeimaging for evaluation of problems unrelated to reflux. About 2% of patients had undergone CT scanning or magnetic resonanceimaging, primarily for abdominal pain. Of a total of 33 implants, 21 were low-density blebs, and 12 were high density. None ofthe patients had hydronephrosis, and none had microhematuria.

The researchers concluded that a history of endoscopic injection, absence of hydronephrosis, absence of hematuria, and lack ofvisualization of DxHA implant on plain x-ray should reassure clinicians and prevent misdiagnosed ureteral stones.

Dr. Kirsch is a consultant to Q-Med.