Tubulointerstitial nephritis and uveitis (TINU) syndrome and recent Streptococcus infection in a 9-year-old girl

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.

Renal outcomes in tubulointerstitial nephritis and uveitis (TINU) syndrome: a systematic review and meta-analysis

BACKGROUND

Tubulointerstitial nephritis and uveitis syndrome (TINU) is a rare condition characterised by bilateral uveitis and interstitial nephritis. There is no nationally, or internationally agreed upon treatment regimen. A systematic review was undertaken to report the renal outcomes in TINU, and treatments used.

METHODS

Medline (1969-2021) and EMBASE (1988-2021) databases were searched for primary studies, clinical practice guidelines and case reports of adult and paediatric TINU cases, as defined by Mandeville criteria. Two reviewers identified articles meeting inclusion criteria (registered with PROSPERO). Data were extracted into a synthesis table and meta-analysis performed. Quality of case series was also assessed.

RESULTS

One hundred twenty-two articles were identified, totalling 257 cases included in the meta-analysis. Females were more commonly affected than males (2:1), and median age was 19 years. GFR at follow-up correlated with nadir GFR, and the proportion with GFR <90 ml/min/1.73 m² was statistically different between adult and paediatric groups. Of the entire cohort, 40% had GFR <90 ml/min/1.73 m² at follow-up. Glucocorticoid monotherapy was the most common treatment (70%); other strategies included no treatment (9%) and immunosuppressant drugs (e.g. azathioprine), mostly in steroid-resistant cases, or as 'steroid-sparing' alternatives.

CONCLUSIONS

The majority of literature regarding TINU is limited to case reports and case series. There are no prospective trials assessing the effects of different treatments on renal outcomes, and currently employed treatment strategies are physician-specific without a reliable evidence-base. Prospective data collection as part of multicentre trials should be a research focus to improve the evidence-base.

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.