Clinical characteristics of rotavirus gastroenteritis with urinary crystals.

Background: Rotavirus gastroenteritis is severe and often results in dehydration and pre-renal azotemia. In addition, some patients with acute obstructive uropathy due to ammonium acid urate stones, developing approximately 6-7 days after the onset of rotavirus gastroenteritis, have been reported, mainly in Japan. The pathophysiological mechanism responsible for stone formation has not been clarified. In the present study, we investigated the clinical characteristics of these patients, and analyzed the pathophysiology underlying the formation of urinary stones.

Methods: A total of 164 patients were enrolled. All had acute gastroenteritis due to rotavirus infection and were treated at Osaka Medical College Hospital and affiliated hospitals between January 2009 and May 2011. All were younger than 15 years of age, and their laboratory data, including urinalysis, were available.

Results: Among the enrolled patients, 30 (20 boys and 10 girls aged 0.2-10 years; median, 1.5 years; interquartile range, 1-3 years) had crystals in their urine. Most of the patients were admitted approximately 2 days after onset of gastroenteritis and had hyperuricemia and aciduria. The crystals consisted mainly of uric acid, and rarely of ammonium acid urate.

Conclusion: In order for ammonium acid urate stones to form in patients with acute obstructive uropathy associated with rotavirus gastroenteritis, prolonged continuous acidosis with hyperuricemia, might be necessary. Therefore, normalization of metabolic acidosis is important in order to prevent the onset of obstructive uropathy associated with rotavirus gastroenteritis.