Long-term outcome of biopsy-proven idiopathic tubulointersitial nephritis with or without uveitis in children\u2014a nationwide follow-up study

Sari Rytkönen,Janne Kataja,Pekka Arikoski,Timo Jahnukainen,Matti Nuutinen,Kira Endén,Ville Saarela,Juuso Tainio

doi:10.1007/s00467-021-05060-5

Abstract

BackgroundOnly a few studies reporting the long-term outcome of children with idiopathic tubulointerstitial nephritis (TIN) and uveitis syndrome (TINU) are available. We studied the long-term kidney and ocular outcome in a nationwide cohort of children with TIN or TINU.MethodsAll patients followed up for a minimum of 1 year by a paediatrician and an ophthalmologist were enrolled. The data on plasma creatinine (P-Cr), estimated glomerular filtration rate (eGFR), proteinuria, hypertension and uveitis were collected retrospectively.ResultsFifty-two patients were studied. Median age at time of diagnosis was 13.1 (1.8–16.9) years and median follow-up time was 5.7 (1.1–21.2) years. Forty-five (87%) patients were initially treated with glucocorticoids. The median of the maximum P-Cr was 162 μmol/l (47–1,016) and that of eGFR 47 ml/min/1.73m2 (8–124). Uveitis was diagnosed in 33 patients (63%) and 21 (40%) patients developed chronic uveitis. P-Cr normalised in a median of 2 months. Eleven (21%) patients had nephritis recurrence during or after discontinuation of glucocorticoids. At the latest follow-up, 13 (25%) patients had eGFR < 90 ml/min/1.73m2 (median 83; 61–89 ml/min/1.73m2). Six patients had tubular proteinuria; all presented with TIN without uveitis. Seven (13%) patients were hypertensive. Eleven (21%) patients had uveitis. One patient developed uraemia and was later transplanted.ConclusionsOur study questions the previously reported good long-term kidney and ocular outcome of patients with TIN/TINU. Decreased kidney function and/or ocular co-morbidities may persist for several years; thus, both kidney and ocular follow-up for at least 1 year is warranted.Graphical abstractA higher resolution version of the Graphical abstract is available as Supplementary information

Highlights

Tubulointersitial nephritis (TIN) is an inflammatory disease affecting primarily the renal interstitium and tubular wall without significant glomerular or vascular involvement [1]
TIN can sometimes be accompanied by uveal inflammation, in which case it is referred to as tubulointerstitial nephritis and uveitis (TINU syndrome)
TIN and uveitis can be associated with systemic immunologic conditions such as sarcoidosis, systemic lupus erythematosus or inflammatory bowel disease [6,7,8]

Summary

Introduction

Tubulointersitial nephritis (TIN) is an inflammatory disease affecting primarily the renal interstitium and tubular wall without significant glomerular or vascular involvement [1]. TIN is a rare but significant cause of acute kidney insufficiency in children, accounting for approximately 7% of acute kidney injuries (AKI) in the paediatric population [9]. It is usually considered a condition with good long-term prognosis. There is evidence that some patients develop permanent kidney impairment, but studies reporting long-term outcomes of TIN/TINU syndrome in the paediatric population are scarce and follow-up times have been short [2, 4, 10,11,12]. A few studies reporting the long-term outcome of children with idiopathic tubulointerstitial nephritis (TIN) and uveitis syndrome (TINU) are available.

Objectives

Methods

Results

Conclusion