Objective:To explore clinicopathological features and prognosis of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in children induced by antithyroid drugs.Methods:The clinicopathological features, treatment and prognosis of 3 children with AAV induced by antithyroid drugs in the Department of Pediatric Nephrology and Rheumatology of the First Affiliated Hospital of Sun Yat-sen University were analyzed retrospectively, and the literatures were reviewed.Results:(1) Among the 3 cases, there were 2 females and 1 male, whose ages were 12.6, 13.9 and 13.1 years old, respectively. All patients had medication history of propylthiouracil (PTU) and/or methimazole (MMI) before onset. Initial manifestation was pallor and renal involvements with nephrotic proteinuria, hematuria and renal function abnormality, while 2 of them had hypertension. Extrarenal manifestations were also presented: case 1 presented with rash, arthralgia and cardiac insufficiency; case 2 had brain involvement with repeated convulsions; case 3 presented with arthralgia and lung involvement. They were all tested positive for p-ANCA and MPO-ANCA. Initial renal histopathology of the 3 cases were consistent with ANCA-associated glomerulonephritis, which were classified into sclerosis, crescentic and mixed class respectively. After 8 months of treatments, repeated renal biopsy of case 3 had demonstrated progression to sclerosis class. Antithyroid drugs (PTU or MMI) were discontinued in 3 cases, and the children were all treated with corticosteroid combined with intravenous pulse cyclophosphamide therapy. Plasma exchange was performed in case 2 and case 3 due to rapidly progressive glomerulonephritis and disease recurrence (suspected pulmonary hemorrhage), respectively. Case 3 was treated with rituximab combined with mycophenolate mofetil after recurrence. The extrarenal symptoms relieved quickly after treatments in all cases. P-ANCA and MPO-ANCA became negative in case 1 and case 2 after 6 months of treatments but they were persistently positive in case 3. Three cases were followed up for 24 months, 10 months and 12 months, respectively: case 1 develop chronic kidney disease (CKD) stage 2 with normal urinalysis; case 2 develop CKD stage 5 and had sudden death at home at 10-month follow-up; case 3 develop CKD stage 4 with nephrotic proteinuria and microscopic hematuria. (2) There were totally 30 pediatric cases with AAV induced by PTU and MMI, including 27 reported cases in the literature and 3 cases in this study. Symptoms of AAV appeared in children after an average administration of (37.5±4.0) months of PTU (range from one month to 96 months and 8 months of MMI alone). Kidney (28 cases, 93.3%) and lung (12 cases, 40.0%) were commonly involved, while brain (2 cases, 6.7%) was rarely involved. The pathological changes of kidney were crescent nephritis (5/23) and necrotizing pauci-immune complex nephritis (11/23). The total remission rate was 93.3% (28/30) after antithyroid drugs withdrawal and treatment with corticosteroids and immunosuppressive therapy, however, there were still severe cases with progression to CKD stage 5, and death. (3) Thirty cases were divided into complete response group ( n=19) and incomplete response group ( n=11) according to the treatment response. Compared with complete response group, the proportions of massive proteinuria (8/11 vs 5/19), fibrinoid necrosis (7/9 vs 4/14), deposition of immune complex in renal tissues (6/9 vs 2/14) and administration of immunosuppressants (10/11 vs 5/19), and degree of tubular atrophy (0/1/2/3 grade, 2/4/2/1 vs 9/5/0/0) in incomplete response group were higher (all P<0.05). Conclusions:PTU and MMI can both induce AAV in children, and AAV may occur after short-term course of administration. Kidney and lung are commonly involved while brain involvement is rarely seen. Timely withdrawal of antithyroid drugs and proper treatments with corticosteroids and immunosuppressants can result in high remission rate, though there are still some severe cases. Nephrotic-range proteinuria, renal fibrinoid necrosis, immune-complex deposition and tubular atrophy may be the risk factors of AAV for poor prognosis.

Objective:To compare the consistency in diagnosing and staging acute kidney injury (AKI) in children with chronic kidney disease (CKD) according to three criterias.Methods:Children with CKD hospitalized in the First Affiliated Hospital of Sun Yat sen University from January 2013 to December 2019 were analyzed retrospectively. These patients underwent serum creatinine examination more than twice during hospitalization. The AKI diagnosis and staging were performed for each patient according to the 2007 pRIFLE, 2012 KDIGO and 2018 pROCK criteria respectively. All the children were followed up for 1 year after discharge through outpatient visit, re-hospitalization or online consultation. The clinical characteristics and prognosis of CKD children with or without AKI that were diagnosed by 3 criteria were compared. Analysis of variance and chi-squared tests were used for the comparison among groups. Concordance between the different diagnostic criteria was evaluated using Cohen′s kappa coefficient.Result:A total of 2 551 children with CKD were included in this study, with an age of (8±4) years. There were 1 628 boys and 923 girls. Nephrotic syndrome was the most prevalent primary disease (55.4%), followed by lupus nephritis (11.2%) and purpura nephritis (8.2%). Among all stages of CKD, CKD category G1 was the most common type (2 146 cases, 84.1%), followed by CKD category G2 (221 cases, 8.7%). AKI occurence rates according to pRIFLE, KDIGO and pROCK criteria were 33.9% (866/2 551), 26.2%(669/2 551) and 19.5% (498/2 551) respectively (χ2=136.3, P<0.01). The diagnostic consistency within three criteria for AKI was high in children with CKD ( κ=0.702), but AKI staging consistency was low ( κ=0.329). Both the diagnosis and staging consistency of three AKI criteria were poor in children with CKD category G5 (all κ<0.400). The length of hospital stay (LOS), hospitalization costs, the occurence of intensive care unit (ICU) admission and in-hospital mortality were significantly higher in children with AKI diagnosed by different criteria ( P<0.05). After 1-year follow-up, the repeated admission rate and CKD staging progress significantly increased in children with AKI ( P<0.05). In children with baseline serum creatinine≥200 μmol/L, compared with children who did not experience AKI during hospitalization, the LOS and the hospitalization costs in children who were diagnosed AKI according to pRIFLE or pROCK criteria was significantly higher ( P<0.05). However, there was no significant difference in the LOS and hospitalization costs between children with or without AKI who were diagnosed according to KDIGO criteria (all P>0.05). Conclusions:AKI diagnosed by all of the three criteria (pRIFLE, KDIGO and pROCK criteria) was associated with the poor prognosis in children with CKD. However, in those whose baseline serum creatinine≥ 200 μmol/L, AKI diagnosed by pRIFLE and pROCK criteria could better reflect the poor outcomes than by KDIGO criteria.