BACKGROUND Acute tubulointerstitial nephritis (AIN) is an uncommon cause of acute kidney injury in children, accounting for less than 10% of cases. There is limited information regarding the range of underlying diagnoses and how these may differ geographically. We undertook a retrospective case note review of consecutive cases of biopsy-proven AIN, presenting to a single UK tertiary paediatric centre, to describe the range of AIN in our caseload, define key characteristics and response to treatment, with the aim of informing paediatric nephrology practice. METHODS Cases were identified retrospectively from departmental records. Data extracted included demographics, presenting clinical and biochemical features, renal biopsy histology, treatment and follow-up. RESULTS Ten cases were identified over 8 years (2007-2014). Age range 6-16 years. Male:Female ratio 1:9. Final diagnoses included 6 tubulointerstitial nephritis and uveitis syndrome (TINU), 2 idiopathic, 1 sarcoidosis, 1 child with Streptococcal disease. Of the TINU cases, timing of eye symptoms varied in relation to AIN presentation. Cases had a varied investigative work-up. Median presenting plasma creatinine was 303 μmol/l (range 152-932 μmol/l). Renal function improved spontaneously in 1 idiopathic case and improved with antimicrobial treatment in a child with Streptococcal disease. Eight cases received immunosuppressive treatment with intravenous methylprednisolone (approximately 10 mg/kg for 3-5 days) and / or oral prednisolone (1-2 mg/kg initially, reducing over 7-28 days). At 1 month, median creatinine had fallen to 91 μmol/l (range 41-120 μmol/l) with median eGFR 61 ml/min/1.73m2 (range 51-103 ml/min/1.73m2). At last follow-up (median 18.5 months, range 2-70 months), median creatinine was 71 μmol/l (range 47-90 μmol/l) with median eGFR 80 ml/min/1.73m2, range 63 to 101 ml/min/1.73m2). Two patients received antihypertensives at diagnosis and 1 further patient at 1 month follow-up. Eight patients received electrolyte supplementation. Median time to discontinuing electrolyte supplementation was 3.5 months (range 1-12 months). CONCLUSION To our knowledge, this is the only contemporary UK case series of biopsy-proven AIN in children. Our population has a high proportion of TINU. Treatment was accompanied by improvement of renal function, however 7/10 patients had an eGFR < 90 ml/min/1.73m2 at last follow-up. We suggest a standardised investigative work-up and recommend long-term follow-up.

中文翻译：

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儿童急性肾小管间质性肾炎——英国三级儿科中心的回顾性病例系列。


背景急性肾小管间质性肾炎（AIN）是儿童急性肾损伤的罕见原因，占病例的不到10%。关于潜在诊断的范围以及这些诊断在地理上的差异的信息有限。我们对经活检证实的 AIN 连续病例进行了回顾性病例记录审查，提交给英国一家三级儿科中心，描述我们病例中 AIN 的范围，定义关键特征和对治疗的反应，目的是为儿科肾脏病学提供信息实践。方法 从部门记录中回顾性地确定病例。提取的数据包括人口统计、临床和生化特征、肾活检组织学、治疗和随访。结果 8 年（2007 年至 2014 年）期间发现了 10 个病例。年龄范围 6-16 岁。男女比例1:9。最终诊断包括 6 例肾小管间质性肾炎和葡萄膜炎综合征 (TINU)、2 例特发性、1 例结节病、1 例链球菌病儿童。在 TINU 病例中，眼部症状出现的时间因 AIN 表现而异。对案件进行了各种调查处理。血浆肌酐中位数为 303 μmol/l（范围 152-932 μmol/l）。 1 名特发性病例的肾功能自发改善，1 名链球菌病儿童的肾功能通过抗菌治疗得到改善。 8 例患者接受静脉注射甲泼尼龙（约 10 mg/kg，持续 3-5 天）和/或口服泼尼松龙（最初 1-2 mg/kg，7-28 天减少）的免疫抑制治疗。第 1 个月时，中位肌酐降至 91 μmol/l（范围 41-120 μmol/l），中位 eGFR 61 ml/min/1.73m2（范围 51-103 ml/min/1.73m2）。最后一次随访（中位数 18.5 个月，范围 2-70 个月），中位肌酐为 71 μmol/l（范围 47-90 μmol/l），中位 eGFR 80 ml/min/1.73m2，范围 63 至 101 ml/min/1.73m2）。两名患者在诊断时接受了抗高血压治疗，另外一名患者在 1 个月随访时接受了抗高血压治疗。八名患者接受了电解质补充。停止补充电解质的中位时间为 3.5 个月（范围 1-12 个月）。结论 据我们所知，这是英国当代唯一经活检证实的儿童 AIN 病例系列。我们的人口中 TINU 的比例很高。治疗伴随着肾功能的改善，但 7/10 的患者在最后一次随访时 eGFR < 90 ml/min/1.73m2。我们建议进行标准化调查工作并建议长期跟进。