Rotavirus gastroenteritis-associated urinary ammonium acid urate crystals.

Although ammonium acid urate (AAU) calculi are extremely rare renal stone components, it was recently found that many urinary tract calculi that cause post-renal renal failure in rotavirus (RV) gastroenteritis are AAU calculi. The mechanism of AAU calculi development in RV gastroenteritis has not been fully elucidated. We analyzed data from eight RV gastroenteritis patients who transiently had AAU crystals in their urinary sediment. In these patients, formation of AAU crystals occurred earlier than the formation of AAU calculi. No difference was observed in serum and urine uric acid levels between RV gastroenteritis patients with or without AAU crystals. Interestingly, fractional excretion of sodium was extremely low among patients with AAU crystals. These results suggest that the formation of AAU crystals might not be due to excretion of uric acid, but excretion of sodium.

Clinical characteristics of obstructive uropathy associated with rotavirus gastroenteritis in Japan.

AIMS: Rotavirus gastroenteritis is severe and often results in dehydration and pre-renal azotemia. However, we have encountered four children with acute obstructive uropathy associated with acute rotavirus gastroenteritis, and several similar cases have been reported. Therefore, the aim of the present study was to clarify the epidemiology and clinical features of acute obstructive uropathy associated with acute rotavirus gastroenteritis in Japanese children. PATIENTS AND METHODS: We sent questionnaires to all members of the Japanese Society for Nephrology and all authors who had published case reports of this disease in Japan, inquiring about patient age at diagnosis, sex, the type of stones, laboratory data and other factors. RESULTS: 21 reported patients were evaluable, ranging from 0.4 to 3 years. The sex distribution showed a strong male prevalence. Oliguria had appeared about 7 days after the onset of gastroenteritis. Most of the patients showed hyperuricemia and hyponatremia. The stones consisted mainly of ammonium acid urate. The patients were discharged with normal renal function. CONCLUSION: Although obstructive uropathy associated with rotavirus gastroenteritis is very rare, this disease condition should be explored when anuria is refractory to sufficient fluid replacement therapy or when oliguria persists despite recovery of the gastrointestinal symptoms.

Urolithiasis associated with experimental lymphocytic choriomeningitis virus inoculation in Lewis rats.

A high frequency of struvite urolithiasis, hydronephrosis, and other urinary tract lesions developed in a group of Lewis rats inoculated intracranially with lymphocytic choriomeningitis virus (LCMV). Initially, clinically ill rats were referred to necropsy: 30 rats over 3 years. These rats had high frequency of urolithiasis (8/30, 27%), hydronephrosis (12/30, 40%), cystitis (9/30, 30%), transitional cell carcinoma (4/30, 13%), and pyelonephritis (19/30, 63%). Lesions were more common in LCMV-inoculated rats. After this trend was noted, all rats on this protocol were necropsied as part of a cohort study (n = 144). Although the apparent frequency of disease was lower due to increased sampling, there still was a high number of urolithiasis (9/144, 6%) and hydronephrosis (40/144, 28%) cases. All cases of urolithiasis developed in rats inoculated with LCMV (9/44, 20%), as did most cases of hydronephrosis (31/44, 70%). Although sham-injected and uninoculated control rats also had high frequency of hydronephrosis (6/57 [11%] and 3/43 [7%], respectively), LCMV-inoculated rats had a significantly higher frequency of disease than did sham inoculated (P < 0.0001) and uninoculated (P < 0.0001) controls. These results suggest that Lewis rats may be predisposed to developing lesions of the urinary tract, and that intracranial inoculation of rats with LCMV augments this tendency, leading to formation of struvite calculi and associated urinary tract disease.