Congenital Solitary Kidney in Children: Size Matters.

PURPOSE: We assessed renal function outcome in children with congenital solitary kidney and evaluated prognostic risk factors. MATERIALS AND METHODS: We retrospectively studied the clinical charts of 210 children presenting with congenital solitary kidney at 2 pediatric nephrology and 5 pediatric units between January 2009 and October 2012. Children 0 to 18 years old with a congenital solitary kidney confirmed by scintigraphy were enrolled. Of the patients 146 were suitable for analysis. Median followup was 4.6 years. Primary outcome was decreased estimated glomerular filtration rate, and secondary outcome was occurrence of proteinuria and/or systemic hypertension. Primary outcome-free survival analysis was performed, including multiple regression analysis of significant risk factors. RESULTS: Decreased estimated glomerular filtration rate was present in 12% of children at a median age of 2.2 years. Primary outcome-free survival analysis revealed an estimated event-free survival of 82% (95% CI 74% to 91%) at 10 years. Estimated survival rate was significantly decreased in children with additional congenital anomalies of the kidney/urinary tract (54% vs 88% overall) or insufficient renal length vs expected for normal congenital solitary kidney. The latter was the strongest predictor of decreased estimated outcome-free survival (49% vs 89%, p <0.001). Occurrence of proteinuria and/or systemic hypertension was present in less than 5% of children. CONCLUSIONS: Some children with congenital solitary kidney show decreased glomerular filtration rate. Associated anomalies of the kidney/urinary tract and insufficient renal length appear to be significant risk factors. Adequate length of the congenital solitary kidney is a key parameter for maintenance of renal function and should be examined routinely during followup.

Tubulointerstitial nephritis and uveitis syndrome in a twelve-year-old girl.

Tubulointerstitial nephritis and uveitis (TINU) syndrome is a rare disorder defined by the combination of biochemical abnormalities, tubulointerstitial nephritis, and uveitis. We describe a 12-year-old female, presented with a ten-day history of fever, characterized by sudden onset and rapid spontaneous resolution in few hours, accompanied by shivering, extreme fatigue, and loss of appetite. Laboratory values were consistent with renal failure of tubular origin. Renal biopsy confirmed a tubulointerstitial nephritis, with acute tubulitis, polymorphonuclear infiltration, and microabscesses. The renal interstitium was occupied by a dense inflammatory infiltrate, consisting of lymphocytes, plasma cells, and neutrophils. Glomerular structures were preserved. Ophthalmological examination that suggested a previous asymptomatic bilateral uveitis and HLA typing (HLA-DQA1∗0101/0201 and HLA-DQB1∗0303/0503) further supported the suspect of TINU syndrome. TINU syndrome is probably an underdiagnosed disorder, responsible for many cases of idiopathic anterior uveitis in young patients, especially in those who have asymptomatic renal disease and when proper diagnostic tests are not performed at the time of presentation.