A case is reported of anuria and urinary ascites secondary to bilateral ureteropelvic obstruction by fungal balls. Management consisted of bilateral nephrostomy drainage with local irrigation with amphotericin B, and systemic antifungal treatment without surgery. Aspiration by paracentesis was performed for the urinary ascites and continuous drainage through an 8 Fr pig tail catheter for the urinoma. The literature on renal fungus balls in neonates and infants is reviewed.
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The most common urinary fungus is Candida, producing asymptomatic candiduria, cystitis, and, with renal involvement, systemic candidiasis, primary renal candidiasis, and bezoar formation. Most patients have underlying disease or risk factors that favour the occurrence of systemic candidiasis. Predisposing factors described in the literature are prematurity, use of broad spectrum antibiotics, and use of intravenous catheters.1 Renal fungal balls may be a cause of urinary tract obstruction and acute renal failure in these patients. Although several cases of anuria in premature neonates or infants secondary to bilateral ureteropelvic junction obstruction related to fungal balls have been reported, no cases of urinary ascites associated with fungal balls have been described. We report a unique case of anuria and urinary ascites in a premature infant secondary to bilateral ureteropelvic junction obstruction caused by fungal balls.
A 3 month old female infant presented with anuria for 23 hours and abdominal distension. The patient was born as the second twin at 30 weeks gestation and had been treated with broad spectrum antibiotics, parenteral nutrition, central vascular access, and mechanical ventilation for hyaline membrane disease in the neonatal intensive care unit for two months. One month after leaving intensive care, she was readmitted because of anuria and abdominal distension. Mild fever was observed, and laboratory data revealed a white blood cell count of 39.0×109 cells/l, haemoglobin concentration of 85 g/l, and creatinine concentration of 168.0 μmol/l. Ultrasonography showed bilateral hydronephrosis with echogenic contents within the renal pelves, a large cystic mass in the left perinephric space, and ascites (fig 1A). Antegrade pyelography showed both collecting systems to be dilated, with multiple filling defects and extravasations from the upper calyces of the left kidney (fig 1B). Computed tomography showed multiple, small, low density regions in both renal parenchymes, and high density material filled the dilated pelves. A urinoma in the left prerenal space and ascites in the pelvic cavity were also observed (fig 2). Percutaneous nephrostomy on both sides was performed immediately after antegrade pyelography, and urine specimens were sent for analysis and fungal culture. Urinalysis showed many yeast-like cells, and Candida albicans was cultured from the specimens. Systemic antifungal treatment with amphotericin B was started at a test dose of 0.1 mg/kg. The dose was increased gradually in daily increments over a three day period until a full dose of 0.5 mg/kg was achieved. Both renal pelves were irrigated at a rate of 40 mg/h or 45 mg/h every five hours daily with amphotericin B solution (50 mg/l). Continuous irrigation with 1 litre of solution with a slow drip infusion was maintained in both renal pelves. Aspiration by paracentesis was also performed for the urinary ascites, and continuous drainage through an 8 Fr pig tail catheter for the urinoma. After three weeks, the urinary tract obstructions were relieved, which was confirmed by ultrasonography and antegrade pyelography, and the percutaneous nephrostomy catheters were removed. Four weeks later, excretory urography showed good urinary drainage without filling defects within both renal pelves, and the 8 Fr pig tail catheter was removed. Fungal cultures from the urine were negative, and the systemic antifungal treatment was stopped six weeks after it had been started. There were no serious side effects associated with the treatment. The baby was discharged and convalescence was uneventful at the six month follow up.
Systemic candidiasis after intensive care in premature newborns is a well recognised complication, and fungal obstruction of the upper urinary tract in infants is potentially fatal. However, the diagnosis of fungal obstruction in high risk neonates is difficult to make and is often delayed or missed as there are no specific clinical features. Young age, small size, the presence of candidaemia, and withholding antifungal treatment are poor prognostic factors of fungal obstructive uropathy in neonates and infants.2 Mortality in the cases reported to date has been lower after aggressive surgical and medical management. Because yeasts are not always identified in specimens obtained from patients, ultrasonography has been the most useful imaging modality in the early diagnosis of fungal balls.3
For patients with renal fungus balls without complete obstruction, surgical intervention such as placement of a nephrostomy tube is rarely necessary. In non-obstructing bilateral fungal balls, treatment with a combination of liposomal amphotericin B and fluconazole may remove the balls and obviate the need for surgical intervention.4 Oral fluconazole may be a safe and effective alternative for the management of systemic candidiasis in neonates.5 Complications requiring surgery, such as urinary tract obstruction, are uncommon. However, if fungal balls are found to be causing pelvic obstruction, treatment by insertion of bilateral nephrostomy catheters, instillation of amphotericin B into the renal pelvis, and parenteral and/or oral administration of antifungal drugs should be started.6 No guidelines are yet available for the indication, the mode of treatment, and length of treatment in neonates and infants with obstructing fungal balls. Sometimes, surgical removal of bezoars may be necessary to eradicate the fungal infection,7 but not all patients need such an intervention.8
Invasive fungal infections are a major cause of morbidity and mortality in premature newborns. Because it may not always be possible to remove risk factors, a high index of suspicion, prompt diagnosis, and early institution of antifungal treatment are recommended. Our patient was successfully treated with percutaneous nephrostomy and amphotericin B irrigation, coupled with systemic antifungal treatment without surgical removal. Urinary ascites were aspirated by paracentesis, and the urinoma was continuously drained through an 8 Fr pig tail catheter. Anuria resulting from fungal balls in the upper urinary system has rarely been reported. This is a very unusual case of anuria and urinary ascites in a premature infant caused by fungal balls.
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