Therapeutic approach to Candida bezoar in children.
INTRODUCTION
Candida bezoar (CB) is a rare finding in neonates and infants with candiduria, presenting as necrotic debris with proliferating mycelia in the collecting system of the kidney. If initial antifungal medical treatment does not result in clearance of candiduria and disappearance of CB on ultrasound in dilated kidneys, invasive interventions like insertion of nephrostomy tubes (NT) or surgical interventions to drain the kidney are sometimes advocated(.). However, NT placement can be a technical challenge, especially in pre- and dysmature neonates, and NT displacement or obstruction by the CB can lead to suboptimal treatment. Identification of those children who will benefit from invasive renal drainage is important.


OBJECTIVE
This study evaluates the management of patients with CB in three tertiary referral hospitals to determine criteria for intervention.


MATERIALS AND METHODS
A retrospective multicenter chart analysis was conducted of children with candiduria and ultrasonographic demonstration of CB (diagnosed between March 1995 and August 2012). The indication for invasive renal drainage (if performed) and subsequent clinical outcome, serum creatinine levels and ultrasound findings were assessed.


RESULTS
A total of 12 children were included, two of which were premature neonates. Eight children had congenital urogenital anomalies. One older child with acute myeloid leukemia had CB during chemotherapy and one ex-premature developed CB following cerebral candidiasis. All children received systemic antifungal medication; in seven children invasive treatment was added. Indications for invasive treatment were clinical deterioration, progressive renal dilation, pyonephrosis, rising creatinine levels and persistence of CB. Two underwent a Y-cutaneous ureterostomy and nephrostomy tubes were inserted in five children. Percutaneous renal drainage by nephrostomy led to complications in 3 of 6 procedures. In all patients, irrespective of therapeutic modality, follow-up ultrasound demonstrated no de novo changes. No additional parenchymal defects or deterioration of split renal function were seen on DMSA or MAG-3 scan.


DISCUSSION
In the literature renal drainage is suggested in case of complete obstruction. However dilatation is a frequent finding in children as part of the congenital renal anomaly and does not necessarily mean that there is obstruction of the urinary tract. Even in children without candida infections the diagnosis of obstruction is not straightforward, while the results of a MAG 3 scan can be obscured by compromised kidney function, parenchymal bacterial infiltration and neonatal immaturity of the kidney. If candiduria and CB persist despite intensive medical treatment, intensive consultation is required before renal drainage, because NT insertion might be a surgical challenge. Complications such as displacement of the NT, urinoma development, or NT obstruction can occur and was seen in three of six procedures. Premature neonates seem to be more prone to complications due to their small anatomical proportions, requiring medical equipment with small diameters prone to displacement and obstruction. Some studies describe successful pharmaceutical management in the majority of patients with CB. Other studies describe unilateral surgical intervention in children with bilateral CB where unilateral drainage did not influence overall renal outcome. This is in line with our results. A limitation of the present study is its retrospective design. In this population, the motivation for invasive renal drainage or conservative management was not well documented in all cases, and was mainly based on clinical and diagnostic parameters like creatinine levels and radiographic findings.


CONCLUSION
Renal drainage should be considered in selected cases after failure of systemic antifungal treatment. Inserting and maintaining a nephrostomy tube in young children is associated with a high rate of complications; conservative treatment is likely to be sufficient in the majority of patients with candiduria and CB.