Tubulointerstitial nephritis and uveitis syndrome: series of clinical cases

Tubulointerstitial nephritis and uveitis syndrome (TINU) is a rare autoimmune disease that develops predominantly in young people and is characterized by variable clinical manifestations and an uncertain prognosis. A single-center retrospective observational study included 3 pediatric patients (a girl and two boys) with clinically and morphologically confirmed TINU. Age of onset, clinical symptoms, gender-age-height-standardized blood pressure (BP), proteinuria (g/l), excretion level of β2-microglobulin, glucose, phosphorus in urine, blood pH and bicarbonate levels, Bedside Schwartz equation estimated glomerular filtration rate (eGFR, ml/min/1.73 m2, norm≥90 ml/min/1.73 m2), ophthalmoscopy data and the therapy were analyzed at the time of disease manifestation and during the follow-up. The duration of follow-up ranged from 3 to 7 years. The disease debuted at the age of 10 to 14 y/o with severe symptoms of intoxication, inflammatory activity, acute kidney damage (eGFR=22 to 35 ml/min/1.73 m2) and the development of Fanconi syndrome. Anterior uveitis had manifested in 1 to 5 months after the kidney disease. The TINU diagnosis was established after 6 to 9 months from the onset of the disease. All children received systemic steroid therapy coupled with the local treatment for uveitis. A significant decrease in blood creatinine levels and urine β2-microglobulin excretion with partial restoration of renal filtration function was noted by the sixth month of the therapy. All children developed chronic kidney disease (CKD) stages 2 to 3 over time. Stable remission of uveitis was achieved in 2 children after 3 to 10 months of treatment without complications; and in one patient a subacute uveitis led to the secondary changes in the cornea and decreased visual acuity. Conclusion: children with TINU have a high risk of developing CKD as a result of acute kidney disease; uveitis is characterized by a chronic course and, in the absence of remission, can lead to the development of ophthalmological complications.