Clinical outcomes in paediatric tubulointerstitial nephritis and uveitis syndrome (TINU).

Purpose: To evaluate the clinical presentation, course, and outcomes of uveitis in paediatric patients with tubulointerstitial nephritis and uveitis syndrome (TINU).

Methods: Multicentric Retrospective Cohort Study 110 patients ≤21 years of age diagnosed with TINU from 10 sites across the United States and Canada. Clinical diagnosis of TINU required uveitis diagnosed by an ophthalmologist, elevated serum creatinine (SCr) and elevated urine β2-microglobulin (β2M) or abnormal urinalysis. Renal biopsy and systemic illness were not mandatory. Univariate and multivariate analysis was performed to analyse risk factors and treatment modalities.

Results: Median age was 13 years (Range (5.9-18.4); 52% male); median follow-up, 1.6 years (IQR 0.98-4.02). Uveitis was symptomatic in 90%, with bilateral anterior uveitis in 94%. Ninety-two (84%) patients required immunomodulatory treatment (IMT). Methotrexate (n = 44) and mycophenolate mofetil (n = 39) were the first agents after oral corticosteroids. 45% required addition of biologic agents (Adalimumab [n = 33], Infliximab [n = 8]). Younger age (p = 0.018), male sex (p = 0.011), and higher uveitis grade at presentation (p = 0.031) were associated with greater IMT ( ≥ 2) requirement. 53% had uveitis recurrence compared to 16% with nephritis recurrence. At the most recent visit, nephritis was controlled in 90%, while uveitis in 74%. Four (4%) patients required glaucoma surgery. Nine (8%) patients had renal complications.

Conclusions: Most patients with TINU require steroid-sparing IMT for control of uveitis, with nearly half requiring addition of biologic agents. Urinalysis, urine β2M and SCr testing should be considered in children presenting with uveitis, especially when the disease is bilateral and anterior.