Tubulointerstitial Nephritis and Uveitis Syndrome (TINU): A Case Series in a Tertiary Care Uveitis Setting

Background: Tubulointerstitial nephritis and uveitis syndrome (TINU) is a rare disorder typically characterized by sudden-onset non-granulomatous anterior uveitis associated with tubulointerstitial nephritis (TIN). However, the prevalence and clinical features of TINU are still a matter of debate. To add information about TINU, we describe here the clinical features of a series of patients affected by TINU in a retrospective study. Methods: A total of 9358 clinical records of both adult and pediatric patients up to 21 years of age, referred to the Uveitis Center of the Sapienza University of Rome, were examined. The medical records covered a period from 1990 to 2020. Various demographic and clinical features were analyzed in patients who met the criteria for TINU. Results: Twenty-one patients with TINU were identified. TINU was classified as definite, possible, or probable by the currently recognized international criteria. The median age at diagnosis was 14 years (interquartile range 12–35). Females were predominant (15/21, 71.4%). In most cases (14/21, 66.6%), patients developed ocular disease concurrently with renal disease. The most frequent type of ocular involvement was bilateral anterior uveitis (9/21, 42.8%). In two cases, patients presented with bilateral intermediate uveitis; in three cases, they presented with bilateral or unilateral alternating posterior uveitis; and in four cases, they presented with bilateral panuveitis. In one case, the uveitis was anterior in the right eye (OD) and posterior in the left eye (OS), and two cases presented with bilateral asynchronous or unilateral alternating anterior uveitis. All patients received treatment with systemic corticosteroids and topical ocular therapy. At the end of the follow-up, a significant improvement in ocular signs and symptoms with a return to normal visual acuity was generally observed. In all patients, acute kidney injury (AKI) reverted completely and none progressed to chronic kidney disease (CKD). Conclusions: Patients with TINU may often present with atypical uveitis. We suggest that patients with sudden-onset uveitis, even if not bilateral anterior, should be referred to a nephologist for an assessment of the possible presence of renal disease.