Tubulointerstitial Nephritis and Uveitis Syndrome: Case Series and Literature Review

TINU: A Multisystemic Inflammatory Disorder-Case Report and Literature Review

Background. The syndrome of tubulointerstitial nephritis and uveitis (TINU) is a rare oculorenal condition, mainly seen in children and women. The underlying cause of this disease is unknown. Case Presentation. We report a 24-year-old male without any past medical history, diagnosed with bilateral uveitis and azotemia. Biopsy revealed tubulointerstitial nephritis, consistent with TINU syndrome. Fluorescein angiogram revealed peripheral retinal vasculitis. Discussion. TINU is a rare disorder that needs to be distinguished from sarcoidosis, Sjogren's disease, and tuberculosis. Treatment is indicated in patients with progressive renal insufficiency, consisting of steroid therapy. Most patients recover kidney function. Its early recognition is important to offer the best chance of organ preservation.

Tubulointerstitial Nephritis and Uveitis Syndrome During the COVID-19 Pandemic: A Case Series

Objectives

To report the ocular findings, laboratory results, and management of patients with tubulointerstitial nephritis and uveitis syndrome (TINU), whose numbers increased during the 2019 coronavirus disease (COVID-19) pandemic.

Materials and Methods

Demographic characteristics, ophthalmic examination findings, laboratory results including polymerase chain reaction (PCR) test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), serum SARS-CoV-2 immunoglobulin G (IgG) antibody, and treatment of patients diagnosed with TINU between March 2020 and March 2022 were evaluated retrospectively.

Results

The study included 19 eyes of 10 patients (6 female/4 male). The mean age was 13.5±2.4 years (range: 8-16 years). The mean follow-up duration was 13.5±6.1 months (range: 6-24 months). All patients presented with anterior uveitis. Anterior uveitis was bilateral in 9 patients (90%) and unilateral in 1 patient (10%). Posterior segment findings were normal in 8 patients (80%), and bilateral optic disc edema was observed in only 2 patients (20%). None of the patients had a previous SARS-CoV-2 infection and/or vaccination history. The SARS-CoV-2 PCR test was negative in all patients at presentation. The SARS-CoV-2 IgG antibody test was reactive in 7 patients (70%). Recurrent uveitis developed in 8 patients (80%) during follow-up. Systemic immunomodulatory therapy was required for the control of ocular inflammation in 7 patients (70%) with severe uveitis flare-ups.

Conclusion

TINU is a multisystemic autoimmune disease, especially in response to environmental triggering factors such as viral infections. Although TINU is a rare disease, the number of cases increased during the COVID-19 pandemic. SARS-CoV-2 antibodies were detected at a significant rate of 70% in these patients, who did not have a history of SARS-CoV-2 infection and vaccination. Previous asymptomatic SARS-CoV-2 infection in children may be a triggering factor in the development of TINU.

Diagnostic and Management Strategies of Tubulointerstitial Nephritis and Uveitis Syndrome (TINU): Current Perspectives

Tubulointerstitial nephritis and uveitis (TINU) syndrome is a rare autoimmune disease with unclear pathogenesis but probably related to a combination of genetic predisposition and environmental triggers. Diagnosis is challenging due to the asynchronous onset of renal and ocular symptoms, and it is necessary to exclude other causes of nephritis and uveitis. It affects both sexes, with an overall predominance of females and a median age of onset of 15 years. TINU syndrome is characterized by bilateral, non-granulomatous anterior uveitis and tubulointerstitial nephritis, which can cause acute renal failure in severe cases. Several triggers have been identified including concurrent infections, medications, or endocrine diseases. The diagnosis of TINU is mainly based on clinical and analytical findings, and although urinary β2-microglobulin is a useful parameter no specific diagnostic test is available. Current perspectives intend to facilitate its diagnosis identifying susceptibility HLA genotypes, serologic markers and imaging tools to avoid renal biopsy. Treatment options for TINU syndrome include corticosteroids, immunosuppressive agents, and intravenous immunoglobulins, but relapses are frequent, and management can be challenging. The purpose of this review is to provide an updated summary of the diagnostic and treatment strategies of TINU syndrome, helping clinicians recognize and manage this rare autoimmune disorder.

Atypical Presentation of Tubulointerstitial Nephritis and Uveitis Syndrome, a Rare Disease

Purpose

To expand the current knowledge of tubulointerstitial nephritis and uveitis syndrome (TINU), which might assist other ophthalmologists in recognizing and treating patients with this rare disease.

Methods

A patient with atypical demographics and features was compared with previously described TINU cases. The case was analyzed in terms of how it compares with more "classic" cases, and the differences were identified.

Results

The diagnosis of TINU is ultimately clinical, although aided by previous studies. Thus, it might present challenges when patients do not have the typical demographics or presenting features of TINU.

Conclusions

Our patient showed features that deviated from classic TINU. Knowledge of the disease and a comprehensive view of the patient's medical state might help lead to accurate diagnosis and treatment.