Renal outcome and risk factors for end-stage renal disease in pediatric rapidly progressive glomerulonephritis

Biomarkers of histologic severity in children with severe or atypical acute post-streptococcal glomerulonephritis

BACKGROUND

Acute post-streptococcal glomerulonephritis (APSGN) is a common cause of acute kidney injury (AKI) in children; however, in a small subgroup, the presentation is one of rapidly progressive glomerulonephritis (RPGN) deteriorating kidney function associated with severe oligo-anuria or a mixed nephritic-nephrotic picture. This study reviewed potential clinical and laboratory factors which may assist the treating clinician to identify patients at high risk of severe disease.

METHODS

All kidney biopsies for APSGN performed between 1996 and 2020 were obtained from a departmental biopsy database. Clinical and laboratory data were extracted from the patients' clinical records. Kidney biopsies were reviewed and scored independently by a renal histopathologist.

RESULTS

Thirty of 53 (56.6%) patients had stage 3 AKI at initial presentation with a median estimated glomerular filtration rate (eGFR) 27 (IQR 11-41), falling to 20 ml/min/1.73 m2 (IQR 13.3-43) at time of biopsy. Patients who had either a pre-biopsy eGFR < 35 ml/min/1.73 m2 or a ≥ 25% fall in eGFR between admission and biopsy were more likely to have glomerular crescents (p = 0.004). Multivariate regression analysis and receiver operating curve showed the pre-biopsy eGFR most accurately predicted glomerular crescents (p = 0.047, ROC 0.757). There were no significant predictors of nephrotic proteinuria or nephrotic syndrome during the acute phase.

CONCLUSIONS

Severe APSGN is associated with a pronounced reduction in eGFR. Calculation of eGFR in this small group of patients may assist in identifying which patient should have an urgent kidney biopsy to facilitate a more accurate clinical diagnosis and management plan.

Crescentic glomerulonephritis in children: short-term follow-up predicts long-term outcome

Background

Crescentic glomerulonephritis (CrGN) is a relatively rare but severe condition in childhood with the clinical feature of rapidly progressive glomerulonephritis (RPGN). The aim of this study is to investigate the clinicopathological features and prognosis of CrGN in children.

Methods

We retrospectively analyzed the clinical and laboratory data, renal pathological results, treatment, and outcome of 147 CrGN in two Chinese pediatric nephrology centers.

Results

Among the 147 children, there were 22 cases of type I (15.0%), 69 cases of type II (46.9%), and 56 cases of type III (38.1%). The mean percentages of crescents in CrGN I, II, and III were 85.3%, 68.7%, and 73.6%, respectively. The children with type I CrGN presented with more severe clinical manifestations and pathological lesions. The 3-month cumulative renal survival rates of types I, II, and III CrGN were 66.3%, 93.6%, and 75.6%, respectively. The 1-year cumulative renal survival rates of types I, II, and III CrGN were 56.9%, 85.3%, and 73.1%, respectively, and the 5-year cumulative renal survival rates of types I, II, and III CrGN were 33.8%, 73.5%, and 47.1%, respectively. The Kappa Consistency Test between the 3-month and 1-year total renal survival (82.1% vs. 74.7%) of the children was 0.683 (P < 0.001), and between the 1-year and 5-year total renal-free survival (78.3% vs. 69.1%) of the children was 0.476 (P < 0.001). The Bowman's Capsule Rupture (BCR), crescent, interstitial inflammation, and interstitial fibrosis/tubular atrophy (IF/TA) score were predictors of end-stage kidney disease (ESKD) risk but BCR showed better predictive value for ESKD than interstitial inflammation score (P = 0.027) and IF/TA score (P = 0.047).

Conclusion

Patients with type I tended to have the worst renal survival rates. The three-month renal prognosis could partially reflect the 1-year renal prognosis, and the 1-year mortality rate could partially reflect the 5-year mortality rate of children with CrGN.

Acute kidney injury in pediatrics: an overview focusing on pathophysiology

Acute kidney injury (AKI) is defined as an abrupt decline in glomerular filtration rate, with increased serum creatinine and nitrogenous waste products due to several possible etiologies. Incidence in the pediatric population is estimated to be 3.9 per 1,000 hospitalizations, and prevalence among children admitted to intensive care units is 26.9%. Despite being a condition with important incidence and morbimortality, further evidence on pathophysiology and management among the pediatric population is still lacking. This narrative review aimed to summarize and discuss current data on AKI pathophysiology in the pediatric population, considering all the physiological particularities of this age range and common etiologies. Additionally, we reported current diagnostic tools, novel biomarkers, and newly proposed medications that have been studied with the aim of early diagnosis and appropriate treatment of AKI in the future.

Age-dependent survival in rapidly progressive glomerulonephritis: A nationwide questionnaire survey from children to the elderly

Background

Rapidly progressive glomerulonephritis (RPGN) has been known to have a poor prognosis. Although evidence across adult RPGN cases has accumulated over many years, the number of case series in adolescents and young adults has been limited, requiring further studies.

Methods

A total of 1,766 cases from 1989 to 2007 were included in this nationwide questionnaire survey, led by Intractable (former name, Progressive) Renal Diseases Research, Research on intractable disease, from the Ministry of Health, Labour and Welfare of Japan. To elucidate age-related differences in 2-year patient and renal survival rates, the cases were divided into the following four groups: children (0–18 years), young adults (19–39 years), the middle-aged (40–64 years), and the elderly (over 65 years).

Results

Of the 1,766 total RPGN cases, antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis comprised 1,128 cases (63.9% of all RPGN cases), showing a tendency to increase with age. Two-year patient survival for RPGN was 93.9% among children, 92.6% in young adults, 83.2% in the middle-aged, and 68.8% in the elderly. The younger group (children plus young adults) showed a clearly higher survival rate compared to the older group (middle-aged plus elderly) (p<0.05). ANCA-associated glomerulonephritis also showed similar age-related results with all RPGN cases. The comparison of renal prognosis showed no statistically significant differences both in RPGN and in ANCA-associated GN.

Conclusion

The present study described the age-dependent characteristics of the classification of RPGN, especially focusing on a better prognosis of the younger group in patient survival both in RPGN and in ANCA-associated GN.

Acute kidney injury without previous renal disease in critical care unit

BACKGROUND

Acute kidney injury (AKI) is common in hospitalized and critically ill children. Apart from primary kidney disease, etiologies of AKI are usually related to systemic disease and nephrotoxic insult. This study examines the incidence, characteristics, and mortality risks of AKI in critically ill children without primary renal disease or previously known chronic kidney disease.

METHODS

A retrospective cohort study was conducted of patients aged 1-18 years, diagnosed with AKI (excluding severe glomerulonephritis and previously known chronic kidney disease) in pediatric intensive care units between 2013 and 2016. Acute kidney injury was defined according to the Kidney Disease Improving Global Outcomes classifications. Cox proportional hazards regression analysis was employed to assess the relationship between the risk factors and mortality.

RESULTS

Of 1,377 pediatric intensive care unit patients, 253 (18.4%) developed AKI and only 169 (12.3%) who did not have previously known renal disease were included. Of these 169 AKI patients, the mean age was 8.1 ± 4.7 years; 88 (52.1%) patients were male; and 60 (35.5%) patients had AKI stage 3. The most common etiologies of AKI were sepsis (76.9%) and shock (64.5%). Fifty-three (31.4%) of those patients died during admission. The risk factors for death were the need for mechanical ventilation (adjusted hazard ratio, 17.82; 95% CI, 2.41-132.06) and AKI stage 3 (adjusted hazard ratio, 2.32; 95% CI, 1.07-5.00).

CONCLUSIONS

Acute kidney injury in critically ill children without previously known renal disease was approximately two-thirds of the overall incidence. The risk factors of in-hospital death were the use of mechanical ventilation, and AKI stage 3.

Activation of fibroblastic reticular cells in kidney lymph node during crescentic glomerulonephritis

Crescentic glomerulonephritis is an inflammatory condition characterized by rapid deterioration of kidney function. Previous studies of crescentic glomerulonephritis have focused on immune activation in the kidney. However, the role of fibroblastic reticular cells, which reside in the stromal compartment of the kidney lymph node, has not been studied in this condition. We investigated the activation of kidney lymph node-resident fibroblastic reticular cells in nephrotoxic serum nephritis, a classic murine model of crescentic glomerulonephritis. We found that increased deposition of extracellular matrix fibers by fibroblastic reticular cells in the kidney lymph node was associated with the propagation of high endothelial venules, specialized blood vessels through which lymphocytes enter the lymph node, as well as with expansion of the lymphatic vasculature. The kidney lymph node also contained an expanding population of pro-inflammatory T cells. Removal of the kidney lymph node, depletion of fibroblastic reticular cells, and treatment with anti-podoplanin antibody each resulted in reduction of kidney injury. Our findings suggest that modulating the activity of fibroblastic reticular cells may be a novel therapeutic approach in crescentic glomerulonephritis.

Long-term renal outcome in pediatric glomerulonephritis associated with crescent formation

BACKGROUND

Information on long-term renal outcome of pediatric glomerulonephritis associated with crescent formation is limited. A single center retrospective study was conducted to assess long-term renal survival and to determine whether the 2010 classification for antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis can predict renal outcome in pediatric glomerulonephritis associated with crescent formation.

METHODS

Biopsy and clinical data of children, aged ≤ 18 years with ≥ 10 glomeruli and ≥ 10% crescentic glomeruli during January 1998 to December 2015, were reviewed. Biopsies were classified according to the 2010 classification into focal, crescentic, mixed, and sclerotic classes. The clinical endpoint was end-stage renal disease (ESRD).

RESULTS

Of 72 children, 14 patients (19.4%) had positive ANCA. The biopsy indication was rapidly progressive glomerulonephritis in 38 patients (52.8%) and 22 patients (30.6%) required dialysis at onset. Lupus nephritis was the most common diagnosis (43.1%), followed by IgA nephropathy/Henoch-Schoenlein purpura (HSP) (22.2%). ESRD occurred in 18 patients (25%) and the risk of ESRD differed among the histological classifications (p < 0.001). Dialysis at onset and sclerotic class was independent predictors of ESRD in an adjusted model. The risk of ESRD was four-fold higher in patients requiring dialysis at onset and 7.7-fold higher in sclerotic patients than in crescentic patients.

CONCLUSIONS

The probability of ESRD was substantial in pediatric glomerulonephritis associated with crescent formation. The 2010 classification is useful for establishing long-term renal prognosis. Future research is required to validate whether histological classification could be a determinant in therapeutic guideline modification, since long-term renal prognosis is different in each class.