Post-streptococcal glomerulonephritis: Some reduction in a disease of disparities

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.

Predictive factors of progression to chronic glomerulonephritis in pediatric patients with post streptococcal acute glomerulonephritis

BACKGROUND

Post streptococcal acute glomerulonephritis (PSAGN) patients have favorable prognosis, in which most patients showed full recovery in terms of kidney function. However, there is a slight chance ranging from 3 to 6% that PSAGN patients develop chronic kidney diseasewhich may progress into end-stage kidney disease in later life. It is important to identify the factors that can predict the development of chronic glomerulonephritis following PSAGN. Therefore, early intervention can be performed to halt the progression of chronic kidney disease. This study aimed to determine the predictive factors of chronic glomerulonephritis in pediatric patients with PSAGN.

METHODS

This study was an analytical observational study with retrospective cohort design. The accessible population was children within the age of 2-18 years old who were admitted with PSAGN between January 2015 and December 2020 in Dr. Sardjito General Hospital Yogyakarta. All anonymized patient data were evaluated for demographic variables, clinical features, laboratory profiles and outcome. Multivariate analysis was performed with multivariate logistic regression method.

RESULTS

A total of 124 patients with PSAGN were obtained from medical record data. There were 65 patients (52.4%) with chronic glomerulonephritis. Bivariate analysis was performed on assumed predictive factors with the results indicating massive proteinuria with hypoalbuminemia (OR 1.670, 95%CI 1.199-2.326; p = 0.003), oliguria (OR 1.517, 95%CI 1.101-2.089; p = 0.028) and macroscopic hematuria (OR 1.647, 95%CI:1.061-2.555; p = 0.013) were significantly higher in the PSAGN group with chronic glomerulonephritis compared to those without. Results of the multivariate logistic regression analysis showed massive proteinuria with hypoalbuminemia (OR 2.896, 95%CI 1.177-7.123, p = 0.021) and macroscopic hematuria (OR 2.457, 95%CI ,1.018-5.933, p = 0.046) would highly predict chronic glomerulonephritis in subjects with PSAGN.

CONCLUSION

We concluded that massive proteinuria with hypoalbuminemia and macroscopic hematuria are the predictive factors which highly predict chronic glomerulonephritis in PSAGN.

Kidney Health of Indigenous Children: Insights from Australia, Aotearoa New Zealand, and Canada

Purpose of Review

This review seeks to highlight the common and unique factors that impact the kidney health of Indigenous children in Australia, Aotearoa New Zealand, and Canada with a particular interest on efforts to improve their kidney health outcomes and the framework to pursue future efforts.

Recent Findings

In the period since the adoption of the United Nations (UN) Declaration on the Rights of Indigenous People (UNDRIP) there has been a number of studies documenting poorer renal health outcomes and potential causes amongst Indigenous paediatric populations in Australia, Aotearoa New Zealand, and Canada. There is a shortage of studies that look at interventions to improve these outcomes.

Summary

Poorer kidney health outcomes amongst Indigenous children are rarely genetic and appear to be more related to societal inequities. Reported efforts to improve outcomes are few but have demonstrated the ability to make change and with sustained focus on reducing inequities there is hope to improve the renal health of Indigenous children.

C10Pred: A First Machine Learning Based Tool to Predict C10 Family Cysteine Peptidases Using Sequence-Derived Features

Streptococcus pyogenes, or group A Streptococcus (GAS), a gram-positive bacterium, is implicated in a wide range of clinical manifestations and life-threatening diseases. One of the key virulence factors of GAS is streptopain, a C10 family cysteine peptidase. Since its discovery, various homologs of streptopain have been reported from other bacterial species. With the increased affordability of sequencing, a significant increase in the number of potential C10 family-like sequences in the public databases is anticipated, posing a challenge in classifying such sequences. Sequence-similarity-based tools are the methods of choice to identify such streptopain-like sequences. However, these methods depend on some level of sequence similarity between the existing C10 family and the target sequences. Therefore, in this work, we propose a novel predictor, C10Pred, for the prediction of C10 peptidases using sequence-derived optimal features. C10Pred is a support vector machine (SVM) based model which is efficient in predicting C10 enzymes with an overall accuracy of 92.7% and Matthews’ correlation coefficient (MCC) value of 0.855 when tested on an independent dataset. We anticipate that C10Pred will serve as a handy tool to classify novel streptopain-like proteins belonging to the C10 family and offer essential information.

Concomitant rapidly progressive glomerulonephritis and acute rheumatic fever after streptococcus infection: a case report

Acute post-streptococcal glomerulonephritis (APSGN) and acute rheumatic fever (ARF) are common immune-mediated complications after group A streptococcus (GAS) infection. The causative antigenic epitopes on GAS are different for APSGN and ARF, and their simultaneous occurrence is uncommon. A 12-year-old boy presented with fever and gross haematuria. He had subcutaneous nodules on the dorsum of both feet along with a new holosystolic murmur at the apex, and he developed hypertension and generalised oedema after admission. Investigation confirmed the diagnosis of ARF with APSGN. He received a corticosteroid to control inflammation of both the conditions. His clinical signs gradually improved but he still had rheumatic heart disease. As both diseases can occur in the same patient, treatment should be provided for both conditions.Abbreviations: APSGN: acute post-streptococcal glomerulonephritis; ARF: acute rheumatic fever; ASO: antistreptolysin O; Cr: serum creatinine; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; GAS: group A streptococcus; RBC: red blood cells; RPGN: rapidly progressive glomerulonephritis; S1: first heart sound; S2: second heart sound; TTE: transthoracic echocardiogram.

Latency, Anti-Bacterial Resistance Pattern, and Bacterial Infection-Related Glomerulonephritis

BACKGROUND AND OBJECTIVES

Bacterial infection-related GN occurs concurrent to or after known or unknown infections. It is important to understand the clinical implications of the bacterial isolates, antimicrobial resistance patterns, and effect of latency-based classification on kidney and patient outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In total, 501 consecutive adults diagnosed with bacterial infection-related GN between 2005 and 2017 were included from a biopsy registry of 15,545 patients at a single center in South India, and follow-up data were collected from electronic medical records until December 2019. Latency was defined as time between resolution of infection and onset of GN, which was classified as parainfectious, peri-infectious, or postinfectious GN. Longitudinal kidney and patient outcomes were studied.

RESULTS

The mean age of the cohort was 40 (± 15) years, 6% were above 65 years, and 330 (66%) were men. Diabetes was present in 93 (19%) patients. Seventy percent (353 of 501) of patients had known infections, with the median latent period for parainfectious (115 of 353, 33%), peri-infectious (97 of 353, 27%), and postinfectious (141 of 353, 40%) GN being 0, 5 (4-7), and 15 (10-31) days, respectively. The most common predisposing organism was Streptococcus pyogenes (137 of 353, 39%). Drug-resistant nonstreptococcal bacteria were methicillin-resistant Staphylococcus aureus (25%, four of 16), extended-spectrum β-lactamases (20%, 12 of 59), and carbapenem-resistant organisms (10%, six of 59). Twenty of 22 (91%) of the drug-resistant organisms were isolated from the parainfectious group. The most common site of infection was skin in peri- (23 of 97, 24%) and postinfectious GN (61 of 141, 43%), and urinary tract in parainfectious GN (35 of 115, 30%). Of 321 patients with >3 months of follow-up, 48 (15%) developed kidney failure over a median period of 10 (2-37) months and 14 (4%) died. Parainfectious GN, eGFR<30 ml/min per 1.73 m², moderate-to-severe interstitial fibrosis and tubular atrophy, and nontreatment with renin-angiotensin system blockers were significant risk factors for progression to kidney failure by a Cox proportional-hazards model.

CONCLUSIONS

Along with clinical and histologic predictors, parainfectious GN caused predominantly by nonstreptococcal and drug-resistant bacterial infections was associated with poor kidney prognosis.

The economic and health burdens of diseases caused by group A Streptococcus in New Zealand

OBJECTIVES

In preparation for the future arrival of a group A Streptococcus (GAS) vaccine, this study estimated the economic and health burdens of GAS diseases in New Zealand (NZ).

METHODS

The annual incidence of GAS diseases was based on extrapolation of the average number of primary healthcare episodes managed each year in general practices (2014-2016) and on the average number of hospitalizations occurring each year (2005-2014). Disease incidence was multiplied by the average cost of diagnosing and managing an episode of disease at each level of care to estimate the annual economic burden.

RESULTS

GAS affected 1.5% of the population each year, resulting in an economic burden of 29.2 million NZ dollars (2015 prices) and inflicting a health burden of 2373 disability-adjusted life years (DALYs). Children <5 years of age were the most likely age group to present for GAS-related healthcare. Presentations for superficial throat and skin infections (predominantly pharyngitis and impetigo) were more common than other GAS diseases. Cellulitis contributed the most to the total economic and health burdens. Invasive and immune-mediated diseases disproportionately contributed to the total economic and health burdens relative to their frequency of occurrence.

CONCLUSION

Preventing GAS diseases would have substantial economic and health benefits in NZ and globally.

Epidemiology, pathogenesis, treatment and outcomes of infection-associated glomerulonephritis

For over a century, acute 'post-streptococcal glomerulonephritis' (APSGN) was the prototypical form of bacterial infection-associated glomerulonephritis, typically occurring after resolution of infection and a distinct infection-free latent period. Other less common forms of infection-associated glomerulonephritides resulted from persistent bacteraemia in association with subacute bacterial endocarditis and shunt nephritis. However, a major paradigm shift in the epidemiology and bacteriology of infection-associated glomerulonephritides has occurred over the past few decades. The incidence of APSGN has sharply declined in the Western world, whereas the number of Staphylococcus infection-associated glomerulonephritis (SAGN) cases increased owing to a surge in drug-resistant Staphylococcus aureus infections, both in the hospital and community settings. These Staphylococcus infections range from superficial skin infections to deep-seated invasive infections such as endocarditis, which is on the rise among young adults owing to the ongoing intravenous drug use epidemic. SAGN is markedly different from APSGN in terms of its demographic profile, temporal association with active infection and disease outcomes. The diagnosis and management of SAGN is challenging because of the lack of unique histological features, the frequently occult nature of the underlying infection and the older age and co-morbidities in the affected patients. The emergence of multi-drug-resistant bacterial strains further complicates patient treatment.