Acute renal failure due to obstructive uric acid stones associated with acute gastroenteritis

Abstract

Sirs, The development of acute renal failure (ARF) in young children with acute gastroenteritis can lead to a presumptive diagnosis of pre-renal azotemia resulting from diarrheal dehydration. Recently, however, several cases of children with acute post-renal failure due to bilateral obstructive uric acid stones associated with acute gastroenteritis have been reported in Japan [1]. We have also encountered three similar cases in which the serum uric acid concentration was in the lower end of the normal range and fractional excretion of uric acid (FEUA) increased after the patients had recovered. Case 1 was a 3-year-old boy with a 1-week history of rotavirus gastroenteritis and a 2-day history of oligouria. He was referred to our hospital for further examination of the oligouria. He had been healthy prior to the presentation of the gastroenteritis and had no familial history of urolithiasis. On admission, physical examination showed peripheral oxygen saturation (SpO2) of between 80 and 90% for a maximum of 2 l/min supplemental O2. Clinical and laboratory data are summarized in Table 1. Ultrasound scan of the kidney disclosed bilateral dilated pelvises containing debris. Despite adequate fluid control and diuretic therapy, his condition worsened rapidly, desaturating to SpO2 60% for a maximum of 10 l/min supplemental O2, so that he required mechanical ventilation. Emergent computed tomography (CT) disclosed pulmonary edema and bilateral urolithiasis located at the pelviureteric junction (PUJ). Based on these findings, he was diagnosed with severe overhydration resulting from post-renal ARF due to bilateral urolithiasis. Since the anuria continued after 15 h of emergent continuous venovenous hemodiafiltration, percutaneous nephrostomy tubes were inserted bilaterally under ultrasound guidance. Sandy stones excreted through the nephrostomy tubes together with the urine consisted mainly of ammonium acid urate (AAU) (>98%). An antegrade nephrostogram performed on postoperative day (POD) 6 showed residual stones in the left PUJ. The patient therefore underwent left-sided extracorporeal shockwave lithotripsy (ESWL). He was discharged on POD 17. Follow-up ultrasound performed 6 months postoperatively indicated bilateral mild hydronephrosis, but no evidence of stones. Case 2 was a 16-month-old boy with a 3-day history of vomiting and diarrhea. He was initially admitted to a local hospital because of dehydration but was referred to our hospital the following day as he demonstrated prolonged oligouria despite sufficient fluid replacement therapy. He had been previously healthy and had no familial history of urolithiasis. On admission, physical examination revealed mild dehydration. Ultrasound scan of the kidney disclosed bilateral dilated pelvises containing debris, and the abdominal CT scan revealed bilateral urolithiasis at the PUJ. Percutaneous nephrostomy tubes were inserted bilaterally on his second day of hospitalization, and after 48 h of Pediatr Nephrol (2009) 24:2467–2469 DOI 10.1007/s00467-009-1222-x