Repeat renal biopsy in children with severe idiopathic tubulointerstitial nephritis

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.

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.

Tubulointerstitial nephritis and uveitis syndrome: a systematic review

BACKGROUND

Tubulointerstitial nephritis and uveitis (TINU) syndrome is defined as the occurrence of tubulointerstitial nephritis (TIN) and uveitis in the absence of other systemic diseases. The most comprehensive review on this condition was published in 2001.

METHODS

We conducted a systematic review of the literature for cases of TINU syndrome. MEDLINE and Embase databases were screened. Full-length articles or letters reporting cases with both TIN and uveitis were selected. We investigated differences between males and females and paediatric and adult cases. Multivariate analysis was performed to identify potential risk factors for chronic kidney disease (CKD) development.

RESULTS

A total of 233 articles reporting 592 TINU cases were retained for the analysis. The median age of the included subjects was 17 years (interquartile range 13-46) with a female predominance (65%). Uveitis most frequently (52%) followed renal disease and was mostly anterior (65%) and bilateral (88%). Children tended to have more ocular relapses, while they were slightly less likely than adults to suffer from acute kidney injury and to develop CKD. Adult age as well as posterior or panuveitis were associated with an increased risk of developing CKD.

CONCLUSIONS

TINU affects both children and adults, with some differences between these two categories. Adult age and the presence of a posterior uveitis or panuveitis appear to be associated with the development of CKD.

Tubulointerstitial nephritis and uveitis syndrome in an adolescent female: a case report

BACKGROUND

Tubulointerstitial nephritis with uveitis syndrome is a rare disease affecting mainly children and young women. Tubulointerstitial nephritis with uveitis is a diagnosis of exclusion, requiring a high degree of clinical suspicion. Studies report recent infections or certain drugs as precipitating factors of a lymphocytic oculorenal immune response. The prognosis is usually favorable with topical and systemic corticosteroid therapy.

CASE PRESENTATION

We report a literature review and the case of a 14-year-old white girl, who presented to the ophthalmology department with features of one-sided uveitis. Upon transfer of patient to nephrological care, diagnostic work-up revealed renal involvement. Renal biopsy showed a mixed-cell and granulomatous tubulointerstitial nephritis with some noncaseating granulomas, leading to a diagnosis of tubulointerstitial nephritis with uveitis syndrome. With topical ocular and systemic corticosteroid therapy, the patients' condition improved over several weeks.

CONCLUSIONS

Our case highlights the importance of early recognition and treatment of this syndrome, where cross-specialty care typically leads to a favorable outcome.

Long-term clinical characteristics and renal prognosis of children with tubulointerstitial nephritis and uveitis syndrome

BACKGROUND

Tubulointerstitial nephritis and uveitis (TINU) syndrome is a rare disease, especially in children. Owing to the short-term observational period and the small number of patients analyzed in previous reports, the long-term clinical and laboratory characteristics and renal prognosis of children with TINU syndrome remain unclear.

METHODS

In this retrospective observational study, we enrolled 29 children with TINU syndrome from February 1990 to February 2019.

RESULTS

During the median follow-up duration of 38 months, the kidney function, urinary β2 microglobulin-creatinine ratio (U-β2MG/Cr), and uveitis in the patients had significantly improved at 24, 6, and 36 months after diagnosis. Higher U-β2MG/Cr was associated with longer duration of kidney function normalization. Half of the patients required uveitis treatment for 5 years after the diagnosis.

CONCLUSIONS

Patients with severe low-molecular weight proteinuria at diagnosis needed a longer duration to achieve improvements in kidney function. Uveitis has a much longer treatment period than tubulointerstitial nephritis. This study demonstrates the good prognosis of children with TINU syndrome in terms of their long-term clinical and laboratory characteristics.

Tubulointerstitial nephritis and uveitis (TINU) syndrome: a review

Inflammation of renal interstitium and uveal tissue establishes the two components of tubulointerstitial nephritis and uveitis (TINU) syndrome. Although believed to occur more frequently in young females, a broad spectrum of patients can be affected. Both renal and eye disease can be asymptomatic and may not manifest simultaneously, having independent progressions. Renal disease manifests as acute kidney injury and may cause permanent renal impairment. Eye inflammation can manifest in different anatomical forms, most commonly as bilateral anterior uveitis and may progress to a chronic course. TINU syndrome accounts for approximately 1%–2% of uveitis in tertiary referral centres. A literature review covering the clinical features, pathogenesis, diagnosis and treatment is presented.

Tubulointerstitial nephritis and uveitis syndrome in children: report of three cases

Tubulointerstitial nephritis and uveitis syndrome is a rare and probably underdiagnosed condition. Renal and ocular manifestations may not occur simultaneously, making the diagnosis more difficult. Nephritis may be asymptomatic; therefore, renal function evaluation is essential for diagnosis. Urinary β2-microglobulin levels may be particularly useful. Uveitis, mostly anterior, nongranulomatous and bilateral, occurs usually after the onset of nephritis. Treatment includes corticosteroids and, eventually, other immunosuppressant agents. Renal disease is usually benign and resolves spontaneously or after treatment with systemic corticosteroids. Uveitis, however, may be chronic or recurrent. The authors described the cases of three pediatric patients diagnosed with tubulointerstitial nephritis and uveitis syndrome. The goal of this paper was to warn the medical community over the need to screen patients with uveitis for renal disease.

Tubulointerstitial nephritis and uveitis

PURPOSE OF REVIEW

Tubulointerstitial nephritis and uveitis (TINU) is an important yet underrecognized ocular inflammatory syndrome. This review summarizes key historical publications that identified and defined the syndrome, and more recent literature that reveal the importance of urinary β2-microglobulin testing and kidney biopsy in the diagnostic evaluation of patients with TINU. Additionally, research studies providing new insights into disease pathogenesis are highlighted.

RECENT FINDINGS

In contrast with initial reports of TINU manifesting exclusively as an anterior uveitis in pediatric patients, more recent reports have identified TINU in patients of all ages with a wide range of ocular manifestations. Urinary β2-microglobulin has emerged as a sensitive and specific laboratory screening test, and the role of kidney biopsy in differentiating TINU from sarcoidosis continues to evolve. Genetic studies have identified HLA-DQA101, HLA-DQB105, and HLA-DRB101 as high-risk alleles and the identification of antimonomeric C-reactive protein antibodies suggests a role for humoral immunity in disease pathogenesis. Management strategies have evolved to include systemic anti-inflammatory treatment as a result of important outcome studies in patients with significant renal and ocular disease.

SUMMARY

With greater recognition, understanding, and treatment of this syndrome, both ocular inflammation and renal disease can be better addressed.

Prednisone in the treatment of tubulointerstitial nephritis in children

BACKGROUND

Patients with tubulointerstitial nephritis (TIN) may develop permanent renal impairment. However, there are no prospective studies available on the treatment of TIN.

METHODS

The effect of prednisone in the treatment of TIN was evaluated in a total of 17 patients who received prednisone or who were followed up without medication. The patient group was subdivided based on the initial plasma creatinine (PCr), below or above 150 μmol/l.

RESULTS

All prednisone-treated patients had normal plasma creatinine (PCr) after 1 month of treatment (median 59.1 [45-85] μmol/l) whereas only 50 % of patients in the non-treatment group had normal creatinine (median 81.0 [42-123] μmol/l) at the same time point (p = 0.025). During 6 months' follow-up, PCr decreased in all patient groups; however, it decreased significantly only in prednisone-treated patients with baseline PCr >150 μmol/l (p < 0.001). At the end of follow-up, no difference in PCr, glomerular filtration rate (GFR), or low molecular weight (LMW) proteinuria could be found between the study groups. A considerable number of patients in both groups had subnormal GFR and/or persistent LMW proteinuria at the 6-month follow-up visit. Eighty-two percent of the patients had uveitis.

CONCLUSIONS

Prednisone speeds up the recovery from renal symptoms of TIN, especially in patients with severe nephritis. The renal function did not differ significantly between prednisone and control patients after 6 months' follow-up.

A rare case of acute renal failure due to tubulointerstitial nephritis and uveitis syndrome successfully treated with steroid

We hereby describe a 49-year-old woman with acute renal failure due to tubulointerstitial nephritis and uveitis (TINU) syndrome. This patient presented with vomiting and nausea and was found to have chronic uveitis, elevated creatinine, and interstitial nephritis. The combination of tubulointerstitial nephritis and uveitis emerged the diagnosis of TINU syndrome after a stepwise examination for differential diagnosis. Clinical course and renal function improved quickly on oral steroids but not to normal range. TINU syndrome, although known to some ophthalmologists and nephrologists, is still rather obscure. TINU syndrome should be considered in patients with uveitis in combination with acute renal failure. The prognosis for the renal disorder is excellent, although the uveitis often recurs or remains chronic.

Tubulointerstitial nephritis and uveitis syndrome in children: a prospective multicenter study

PURPOSE

To evaluate the occurrence and characteristics of uveitis related to tubulointerstitial nephritis (TIN) in children.

DESIGN

Prospective, observational, multicenter, partly placebo-controlled treatment trial.

PARTICIPANTS

Nineteen children with a biopsy-proven TIN.

METHODS

Patients were treated with prednisone or followed without treatment. In addition to the nephrologic evaluations, the prospective follow-up included structured ophthalmological examinations at the onset of TIN and at 3 and 6 months after the diagnosis.

MAIN OUTCOME MEASURES

Occurrence, clinical features, and outcome of uveitis.

RESULTS

Some 84% (16/19) of the patients had uveitis, 83% (5/6) in the nontreatment group and 82% (9/11) in the prednisone-treated group. The remaining 2 patients, originally in the nontreatment group, were switched to the prednisone group after 2 weeks. Both of them developed uveitis. Altogether, 3 patients developed uveitis during prednisone treatment and 2 patients showed worsening of uveitis despite the systemic corticosteroid. Some 50% (8/16) of the patients with uveitis presented with no ocular symptoms; 88% (14/16) of the patients had a chronic course of uveitis. Two patients were diagnosed with uveitis before nephritis; nephritis and uveitis were diagnosed within 1 week from each other in 7 patients, and uveitis developed 1 to 6 months after the diagnosis of TIN in 7 patients.

CONCLUSIONS

There was no statistically significant difference in the occurrence of uveitis in patients with TIN in the prednisone and nontreatment groups. In this study, the occurrence of uveitis associated with TIN was considerably higher than previously reported. Uveitis related to TIN may develop late and is often asymptomatic. The ophthalmological follow-up of all patients with TIN is warranted for at least 12 months starting with 3-month intervals.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any material discussed in this article.

Clinical outcome and occurrence of uveitis in children with idiopathic tubulointerstitial nephritis

Acute idiopathic tubulointerstitial nephritis (TIN) is considered a condition with a good long-term prognosis. However, there is evidence that some patients develop permanent renal impairment. The aim of this study was to evaluate the clinical characteristics of TIN at the time of diagnosis in children and determine whether the findings upon presentation predict renal outcome. The clinical data and biopsy findings from 26 children with idiopathic TIN admitted to four Finnish university hospitals were analyzed retrospectively. Twenty-five patients (96%) manifested renal insufficiency. After the mean follow-up time of 2.75 years (SD 2.5; 0.9-13.5), 4 patients (15%) had permanent renal insufficiency and 8 patients (31%) had persistent low-molecular weight proteinuria. Uveitis was found in 12 patients (46%). Four of these patients (33%) developed chronic uveitis. Our analysis showed that none of the laboratory or biopsy findings upon presentation prognosticated renal outcome. No correlation between renal disease and uveitis could be found either. The occurrence of uveitis among TIN patients was higher than previously reported. Uveitis may develop late and without recurrence of renal dysfunction. Therefore, follow-up by a pediatrician and by an ophthalmologist is warranted in children with acute TIN for at least 12 months from diagnosis.

Serial renal biopsies in three girls with tubulointerstitial nephritis and uveitis syndrome

Tubulointerstitial nephritis and uveitis (TINU) syndrome is considered to have a good prognosis even without any immunosuppressive therapy, although there is no histological evidence to support this. The objective of this study was to evaluate, retrospectively, serial renal biopsy findings in three girls with TINU syndrome who were treated with prednisolone. At presentation, all patients had significantly elevated urinary beta(2)-microglobulin levels (7583-19,313 microg/l) and high serum creatinine levels (0.93-1.3 mg/dl). The elevated beta(2)-MG and creatinine levels persisted for 1 month, and renal biopsies were performed to establish a definitive diagnosis. The initial biopsy specimens of all patients revealed marked interstitial enlargement consisting of infiltration of lymphocytes; there was also notable tubulitis and infiltration of eosinophils. All patients received prednisolone therapy following the diagnosis. A second renal biopsy was performed 9 months after the first biopsy for two of three patients, and 2 years later for the third patient. The biopsy specimens taken at 9 months still showed histological changes of acute inflammation; in contrast, that taken at 2 years showed a lower degree of acute inflammation, but scar formation was observed in some regions. Based on these results, we conclude that selected TINU syndrome patients require some immunosuppressive therapy.

A case of tubulointerstitial nephritis and uveitis syndrome with severe immunologic dysregulation

Idiopathic tubulointerstitial nephritis and uveitis (TINU) syndrome is an uncommon condition, characterized by acute tubulointerstitial nephritis (TIN) with a favorable course and uveitis with a chronic relapsing course. The pathogenesis remains unclear, but a lymphocyte-mediated immune mechanism has been suggested. A 9-year-old boy was evaluated for fatigue and 2 kg of weight loss. Renal glucosuria, elevated urine beta(2)-microglobulin (MG), progressive renal dysfunction, polyclonal hypergammaglobulinemia, various autoantibodies and abnormal lymphocyte phenotypes were found. A renal biopsy revealed acute TIN. After 2 months of treatment with prednisolone, renal function and polyclonal hypergammaglobulinemia were normalized. While tapering prednisolone, anterior uveitis developed, which was improved with topical steroid. But abnormal lymphocyte phenotypes and autoantibodies persisted on low-dose prednisolone. Uveitis became aggravated, and urine beta(2)-MG increased again. The second renal biopsy (7 months later) was normal except for minimal focal interstitial fibrosis. Uveitis was not responsive to systemic steroids, but improved with additional cyclosporin. Abnormal lymphocyte phenotypes improved, and most autoantibodies disappeared. We report a rare case of idiopathic TINU syndrome with severe immunologic dysregulation, which correlated with the clinicopathological and biochemical parameters. The information about lymphocyte phenotypes and autoantibodies may provide more insight into the pathophysiology and the clinical course of uveitis in this rare disorder.