Acute post-streptococcal glomerulonephritis in children of French Polynesia: a 3-year retrospective study

Clinical profile of children with acute post-streptococcal glomerulonephritis

BACKGROUND

Acute post-streptococcal glomerulonephritis (APSGN) is common in developing countries with a high hospitalization rate. Most patients have acute nephritic syndrome features, although some occasionally present with unusual clinical features. This study aims to describe and analyze clinical features, complications, and laboratory parameters in children diagnosed with APSGN at presentation, 4 and 12 weeks later, in a resource-limited setting.

METHODS

This cross-sectional study was conducted among children < 16 years with APSGN between January 2015 and July 2022. Hospital medical records and outpatient cards were reviewed for clinical findings, laboratory parameters, and kidney biopsy results. Descriptive analysis of multiple categorical variables was performed using SPSS version 16.0 and presented as frequencies and percentages.

RESULTS

The study included 77 patients. Most (94.8%) were older than five years, and age group 5-12 years had highest prevalence (72.7%). Boys were affected more frequently than girls (66.2% vs. 33.8%). Edema (93.5%), hypertension (87%), and gross hematuria (67.5%) were the most frequent presenting symptoms, and pulmonary edema (23.4%) was the most common severe complication. Anti-DNase B and anti-streptolysin O titers were positive in 86.9% and 72.7%, respectively, and 96.1% had C3 hypocomplementemia. Most clinical features resolved in three months. However, at 3 months, 6.5% of patients had persistent hypertension, impaired kidney function, and proteinuria alone or in combination. Most patients (84.4%) had an uncomplicated course; 12 underwent kidney biopsy, 9 required corticosteroids, and 1 required kidney replacement therapy. There was no mortality during the study period.

CONCLUSION

Generalized swelling, hypertension, and hematuria were most common presenting features. Persistent hypertension, impaired kidney function, and proteinuria persisted in a small proportion who had a significant clinical course and required kidney biopsy. A higher resolution version of the Graphical abstract is available as Supplementary information.

Predictors of rapidly progressive glomerulonephritis in acute poststreptococcal glomerulonephritis

BACKGROUND

Acute post-streptococcal glomerulonephritis (APSGN) is an immune-mediated inflammatory respsonse in the kidneys caused by nephritogenic strains of group A β-hemolytic streptococcus (GAS). The present study aimed to present a large patient cohort of APSGN patients to determine the factors that can be used for predicting the prognosis and progression to rapidly progressive glomerulonephritis (RPGN).

METHODS

The study included 153 children with APSGN that were seen between January 2010 and January 2022. Inclusion criteria were age 1-18 years and follow-up of ≥ 1 years. Patients with a diagnosis that could not be clearly proven clinically or via biopsy and with prior clinical or histological evidence of underlying kidney disease or chronic kidney disease (CKD) were excluded from the study.

RESULTS

Mean age was 7.36 ± 2.92 years, and 30.7% of the group was female. Among the 153 patients, 19 (12.4%) progressed to RPGN. The complement factor 3 and albumin levels were significantly low in the patients who had RPGN (P = 0.019). Inflammatory parameters, such as C-reactive protein (CRP), platelet-to-lymphocyte ratio, CRP/albumin ratio, and the erythrocyte sedimentation rate level at presentation were significantly higher in the patients with RPGN (P < 0.05). Additionally, there was a significant correlation between nephrotic range proteinuria and the course of RPGN (P = 0.024).

CONCLUSIONS

We suggest the possibility that RPGN can be predicted in APSGN with clinical and laboratory findings. A higher resolution version of the Graphical abstract is available as Supplementary information.

Glomerulonephritis

Glomerulonephritis (GN) encompasses several disorders that cause glomerular inflammation and injury through an interplay of immune-mediated mechanisms, host characteristics, and environmental triggers, such as infections. GN can manifest solely in the kidney or in the setting of a systemic illness, and presentation can range from chronic and relatively asymptomatic hematuria to fulminant renal failure. Classic acute GN is characterized by hematuria, edema, and hypertension, the latter 2 of which are the consequence of sodium and water retention in the setting of renal impairment. Although presenting signs and symptoms and a compatible clinical history can suggest GN, serologic and urinary testing can further refine the differential diagnosis, and renal biopsy can be used for definitive diagnosis. Treatment of GN can include supportive care, renin-angiotensin-aldosterone system blockade, immunomodulatory therapy, and renal transplant. Prognosis is largely dependent on the underlying cause of GN and can vary from a self-limited course to chronic kidney disease. This review focuses on lupus nephritis, IgA nephropathy, IgA vasculitis, and postinfectious GN.

Management and outcomes of acute post-streptococcal glomerulonephritis in children

Acute post-streptococcal glomerulonephritis (APSGN) is the major cause of acute glomerulonephritis among children, especially in low- and middle-income countries. APSGN commonly occurs following pharyngitis due to the activation of antibodies and complements proteins against streptococcal antigens through the immune-complex-mediated mechanism. APSGN can be presented as acute nephritic syndrome, nephrotic syndrome, and rapidly progressive glomerulonephritis, or it may be subclinical. The management of APSGN is mainly supportive in nature with fluid restriction, anti-hypertensives, diuretics, and renal replacement therapy with dialysis, when necessary, as the disease is self-limiting. Congestive heart failure, pulmonary edema, and severe hypertension-induced encephalopathy might occur during the acute phase of APSGN due to hypervolemia. APSGN generally has a favorable prognosis with only a small percentage of patients with persistent urinary abnormalities, persistent hypertension, and chronic kidney disease after the acute episode of APSGN. Decreased complement levels, increased C-reactive protein, and hypoalbuminemia are associated with disease severity. Crescent formations on renal biopsy and renal insufficiency on presentation may be the predictors of disease severity and poor outcomes in APSGN in children.

A Comprehensive Review Study on Glomerulonephritis Associated With Post-streptococcal Infection

Post-streptococcal glomerulonephritis (PSGN) is an immune-complex mediated inflammation that used to be considered one of the commonest causes of acute nephritis amongst children. PSGN is characterized by the proliferation of cellular elements called nephritogenic M type as a result of an immunologic mechanism following an infection of the skin (impetigo) or throat (pharyngitis) caused by nephritogenic strains of group A beta-hemolytic streptococci, a gram-positive bacteria that enters the body across pores in the skin or mucus epithelia and is responsible for more than 500,000 deaths annually due to multiple subsequence diseases such as rheumatic heart disease, rheumatic fever, PSGN, and other invasive infections. After the infection, the formation of an immune complex of antigen-antibody and complement system will take place and will deposit in the glomeruli where the injury occurs and leads to inflammation. The manifestations of PSGN can be explained by nephritic syndrome manifestation. PSGN is diagnosed by laboratory tests like microscopy and urinalysis. The imaging studies in PSGN could be used to assess the possible complications of PSGN such as pulmonary congestion and chronic kidney disease. The management of PSGN is symptomatic. If PSGN is not treated, the patient may develop chronic kidney disease. The main way to prevent PSGN is to treat group A streptococcal (GAS) infections by giving good coverage of antibiotic therapy to a patient who has primary GAS infections to prevent the development of the complication.

Clinical characteristics of acute glomerulonephritis with presentation of nephrotic syndrome at onset in children

BACKGROUND

Acute glomerulonephritis (AGN) is a common disease in children, which places a huge burden on developing countries. The prognosis of it may not always be good. However, the clinical characteristics of AGN with nephrotic syndrome (NS) at onset have not been fully clarified.

METHODS

One hundred and thirteen cases were analyzed retrospectively. Clinical data, pathological results and prognosis between AGN with NS (AGN-NS) and AGN without NS (AGN-no-NS) were compared.

RESULTS

Twenty (17.7%) of 113 patients were AGN-NS. The patients with AGN-NS were more likely to have hypertension (55.0% vs. 25.8%) and acute kidney injury (AKI) (50.0% vs. 17.2%). AKI was significantly related to the manifestation of AGN-NS in children (OR = 3.812, P = 0.040). Compared with the AGN-no-NS, the immunosuppressive treatments were more common in AGN-NS. A more severe pathological grade was significantly related to lower C3 fraction, estimated glomerular filtration rate (eGFR), and AKI, but not to the performance of AGN-NS. There was no difference in prognosis between the two groups.

CONCLUSIONS

AKI was significantly associated with AGN-NS. The prognosis of AGN-NS and AGN-no-NS in our study was almost good. Given the fact that AGN-NS patients are more likely to use immunosuppressive therapy, the long-term outcome of AGN-NS warrants further research.

Acute post-streptococcal glomerulonephritis in Central Australia

OBJECTIVE

To determine the incidence, clinical presentation and progress of acute post-streptococcal glomerulonephritis in Central Australia.

DESIGN

Retrospective observational analysis.

SETTING

Paediatric inpatient admission at Alice Springs Hospital.

PARTICIPANTS

Patients admitted to Alice Springs Hospital under 14 years of age meeting diagnostic criteria for acute post-streptococcal glomerulonephritis between January 2010 and December 2014.

MAIN OUTCOME MEASURES

Incidence of acute post-streptococcal glomerulonephritis in central Australia. Biochemical abnormalities associated with acute post-streptococcal glomerulonephritis. Co-occuring conditions.

RESULTS

Sixty-nine out of the 174 cases reviewed were identified as having either acute post-streptococcal glomerulonephritis (63) or probable acute post-streptococcal glomerulonephritis (6). We calculate the incidence of APSGN admission to be higher than previously reported and the highest reported incidence globally in children. Clinical evidence of skin infection was frequently documented. Co-occurring infections were common, including scabies/head lice, urinary tract infection and pneumonia. Fifty-three patients showed biochemical evidence of acute kidney injury.

CONCLUSIONS

Aboriginal children in Central Australia have the highest incidence of acute post-streptococcal glomerulonephritis reported worldwide. Urgent action is required to improve housing and reduce overcrowding in Central Australian towns and communities to reduce the burden of disease of skin infection and Group A Streptococcus related diseases. Without effective change in living conditions, it is unlikely that there will be a significant change in the morbidity related to these conditions.

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

AIM

A retrospective Auckland-wide (total population approximately 1.4 million) study of hospital admissions from 2007 to 2015 was conducted to assess trends in admissions for acute post-streptococcal glomerulonephritis (APSGN) in children aged 0-14 years.

METHODS

International Statistical Classification of Diseases (ICD10) discharge codes were used to identify potential cases of APSGN, and electronic clinical records and laboratory data were compared with established case definitions for definite or probable APSGN.

RESULTS

A total of 430 cases of APSGN were identified (definite n = 337, probable n = 93), with a mean annual incidence of 15.2/100 000 (95% confidence interval (CI) 14.9-15.6). Incidence (0-14 years) was 17 times higher in Pacific peoples (50.2/100 000, 95% CI 48.6-51.8) and almost 7 times higher in Māori (19.6/100 000, 95% CI 18.6-20.7) than European/other populations (2.9/100 000, 95% CI 2.7-3.1). Multivariate analysis found ethnicity, deprivation, male gender, age (peak 3-8 years) and season (summer/autumn) to be associated with admission risk. Admission rates showed a significant change of -9.0% (95% CI -10.4, 7.4%) per year, with 2011 being an exception. Low C3 complement, hypertension, elevated streptococcal titres, oedema and heavy proteinuria were present in 94, 65, 67, 52 and 49% of cases, respectively. Relying on ICD10 codes without further review of clinical notes would result in an overcount of cases by 25%.

CONCLUSIONS

There is severe disparity in APSGN admission rates, with a disproportionate burden of disease for Pacific and Māori children and those living in deprived circumstances. Rates trended downward from 2007 to 2015.

Infection-Related Glomerulonephritis

Acute postinfectious glomerulonephritis or infection-related glomerulonephritis has been associated with several viral or bacterial infections. Group A beta-hemolytic streptococcal infection is the prototypical cause of postinfectious glomerulonephritis and the main focus of this discussion. The clinical spectrum can vary widely, from asymptomatic microscopic hematuria incidentally detected on routine urinalysis to rapidly progressive glomerulonephritis with acute kidney injury requiring emergent dialysis. Other important causes include glomerulonephritis associated with endocarditis and ventriculoatrial shunt infections. Multiple renal pathologic conditions have been associated with hepatitis B and C infections.

Acute Post-Streptococcal Glomerulonephritis in the Northern Territory of Australia: A Review of Data from 2009 to 2016 and Comparison with the Literature

Acute post-streptococcal glomerulonephritis (APSGN) is an inflammatory kidney disease following infection with nephritogenic strains of Group A Streptococcus. In 1991, APSGN became notifiable in the Northern Territory (NT) of Australia with cases recorded on the NT Notifiable Disease Database (NTNDS). The case definition of a confirmed case requires laboratory definitive evidence or laboratory suggestive evidence in conjunction with a clinically compatible illness. Probable cases require clinical evidence only. Acute post-streptococcal glomerulonephritis notifications from 2009 to 2016 were extracted from the NTNDS. Of the 322 cases, 261 were confirmed and 61 probable. The majority, 304 (94%), were Aboriginal and the median age was 8 years (range: 0-62 years). Incidence for confirmed cases was 13.8/100,000 person-years, with inclusion of probable cases increasing incidence to 17.0/100,000 person-years. Highest incidence of confirmed cases was in Aboriginal children less than 15 years of age at 124.0 cases/100,000 person-years. The rate ratio of confirmed cases in Aboriginal to non-Aboriginal Australians was 18.9 (95% confidence interval: 11.4-33.6). Recent trends show a consistently high number of notifications annually with less frequent outbreaks. The Aboriginal population of the NT continues to have high rates of APSGN with recent trends showing higher rates than previously reported. Sustained preventative efforts and continued surveillance strategies are needed.

Factors associated with treatment outcome of acute post streptococcal glomerulonephritis among patients less than 18 years in Mekelle City, Public Hospitals, North Ethiopia

Objective

To assess factors associated treatment outcomes of acute post streptococcal glomerular nephritis among patients less than 18 years old in Mekelle City Public Hospitals.

Results

About 334 medical records c of children with acute post streptococcal glomerular nephritis were revised during the study period. Of these 244 (73.1%) had a positive outcome. acute post streptococcal glomerular nephritis was found to be statically significant associated with age < 5 years, duration of infection, the source of infection and length of stay in Hospital.

Pediatric post-streptococcal glomerulonephritis: Clinical and laboratory data

BACKGROUND

Acute post-streptococcal glomerulonephritis (APSGN) is the most common post-infectious glomerulonephritis in childhood. The aim of this study was therefore to identify the possible risk factor(s) responsible for decreased glomerular filtration rate (GFR) in APSGN.

METHODS

The data of patients followed up with a diagnosis of APSGN in the Pediatric Nephrology Clinic of Gaziantep University Hospital between October 2014 and October 2016 were retrospectively evaluated.

RESULTS

The total number of subjects was 75 (male/female, 42/33) with a mean age of 8.20 ± 3.25 years. The most common presentations were edema (86.7%), macroscopic hematuria (82.7%) and hypertension (73.3%, n = 55). On laboratory examination, 28 children (37.3%) had hypoalbuminemia, 58 (77.3%) had proteinuria, 20 (26.7%) had increased C-reactive protein (CRP), while 74 (98.7%) and 12 (16%) had decreased complement (C)3 and C4, respectively. The number of children with GFR <90 mL/min/1.73 m² was 22 (29.3%). The risk of decreased GFR was significantly higher in patients with increased CRP (P = 0.001; OR, 3.58), hypoalbuminemia (P = 0.006; OR, 4.83), and decreased C4 (P = 0.010; OR, 11.53). Additionally, white blood cell (WBC) count, neutrophil count, and neutrophil/lymphocyte ratio (NLR) were significantly higher (P = 0.02, P = 0.006, P = 0.004, respectively) in patients with low GFR.

CONCLUSIONS

Although the prognosis of APSGN in children is good, severe systemic complications and renal failure may develop during the follow-up period. Decreased C4, presence of hypoalbuminemia, and increased inflammatory markers (WBC, CRP, neutrophil count and NLR) might be possible risk factors for severity of renal involvement. Decreased C4, in particular, may be a risk factor for decreased GFR in those children.

Partners in crime: neutrophils and monocytes/macrophages in inflammation and disease

Neutrophils are becoming recognized as highly versatile and sophisticated cells that display de novo synthetic capacity and potentially prolonged lifespan. Emerging concepts such as neutrophil heterogeneity and plasticity have revealed that, under pathological conditions, neutrophils may differentiate into discrete subsets defined by distinct phenotypic and functional characteristics. Indeed, these newly described neutrophil subsets will undoubtedly add to the already complex interactions between neutrophils and other immune cell types for an effective immune response. The interactions between neutrophils and monocytes/macrophages enable the host to efficiently defend against and eliminate foreign pathogens. However, it is also becoming increasingly clear that these interactions can be detrimental to the host if not tightly regulated. In this review, we will explore the functional cooperation of neutrophil and monocytes/macrophages in homeostasis, during acute inflammation and in various disease settings. We will discuss this in the context of cardiovascular disease in the form of atherosclerosis, an autoimmune disease mainly occurring in the kidneys, as well as the unique intestinal immune response of the gut that does not conform to the norms of the typical immune system.

Systematic Literature Review on the Incidence and Prevalence of Heart Failure in Children and Adolescents

While the epidemiology of adult heart failure has been extensively researched, this systematic review addresses the less well characterized incidence and prevalence of pediatric HF. The search strategy used Cochrane methodology and identified 83 unique studies for inclusion. Studies were categorized according to whether the HF diagnosis was reported as primary (n = 10); associated with other cardiovascular diseases (CVDs) (n = 49); or associated with non-CVDs (n = 24). A narrative synthesis of the evidence is presented. For primary HF, the incidence ranged from 0.87/100,000 (UK and Ireland) to 7.4/100,000 (Taiwan). A prevalence of 83.3/100,000 was reported in one large population-based study from Spain. HF etiology varied across regions with lower respiratory tract infections and severe anemia predominating in lower income countries, and cardiomyopathies and congenital heart disease major causes in higher income countries. Key findings for the other categories included a prevalence of HF associated with cardiomyopathies ranging from 36.1% (Japan) to 79% (US); associated with congenital heart disease from 8% (Norway) to 82.2% (Nigeria); associated with rheumatic heart diseases from 1.5% (Turkey) to 74% (Zimbabwe); associated with renal disorders from 3.8% (India) to 24.1% (Nigeria); and associated with HIV from 1% (US) to 29.3% (Brazil). To our knowledge, this is the first systematic review of the topic and strengthens current knowledge of pediatric HF epidemiology. Although a large body of research was identified, heterogeneity in study design and diagnostic criteria limited the ability to compare regional data. Standardized definitions of pediatric HF are required to facilitate cross-regional comparisons of epidemiological data.

Post-infectious glomerulonephritis

Post-infectious glomerulonephritis (PIGN) is one of the most common causes of acute glomerulonephritis in children. Although post-streptococcal glomerulonephritis (PSGN) is still common, there is a wide spectrum of causative agents of PIGN. Non-streptococcal organisms are emerging as the main aetiological agents in high-income countries. Nephritis-associated plasmin receptor (NAPlr) and streptococcal pyrogenic exotoxin B (SPeB) are the two common antigens implicated in the pathogenesis of PSGN. Both NAPlr and SPeB activate the alternative complement pathway, resulting in low serum complement levels, and have an affinity to plasmin and glomerular proteins. The clinical presentation of PIGN varies from a benign asymptomatic condition to rapidly progressive glomerulonephritis requiring dialysis. In most cases, PIGN is self-limiting and the evidence base for the treatments used is quite weak. Renal biopsy is indicated when there are atypical features, rapid progression or inadequate recovery, or where an alternative diagnosis has to be considered. IgA-dominant nephritis, endocarditis-associated nephritis and shunt nephritis are special sub-subtypes of PIGN. The prognosis is generally excellent, although long-term follow-up may be needed.

Acute Kidney Injury and Atypical Features during Pediatric Poststreptococcal Glomerulonephritis

The most common acute glomerulonephritis in children is poststreptococcal glomerulonephritis (PSGN) usually occurring between 3 and 12 years old. Hypertension and gross hematuria are common presenting symptoms. Most PSGN patients do not experience complications, but rapidly progressive glomerulonephritis and hypertensive encephalopathy have been reported. This paper reports 17 patients seen in 1 year for PSGN including 4 with atypical PSGN, at a pediatric tertiary care center. Seventeen children (11 males), mean age of 8 years, were analyzed. Ninety-four percent had elevated serum BUN levels and decreased GFR. Four of the hospitalized patients had complex presentations that included AKI along with positive ANA or ANCAs. Three patients required renal replacement therapy and two were thrombocytopenic. PSGN usually does not occur as a severe nephritis. Over the 12-month study period, 17 cases associated with low serum albumin in 53%, acute kidney injury in 94%, and thrombocytopenia in 18% were treated. The presentation of PSGN may be severe and in a small subset have associations similar to SLE nephritis findings including AKI, positive ANA, and hematological anomalies.

Clinical Characteristics and Outcome of Post-Infectious Glomerulonephritis in Children in Southern India: A Prospective Study

OBJECTIVES

To evaluate the clinical characteristics, complications and outcome of post-infectious glomerulonephritis (PIGN).

METHODS

This prospective observational study was conducted from January 2013 through July 2014 at a tertiary care hospital in south India. Post-streptococcal glomerulonephritis (PSGN) was diagnosed in the presence of: a) Hematuria and proteinuria b) Clinico-serological evidence of recent streptococcal infection [recent pyodermas or pharyngitis; positive antistreptolysin-O (ASO) titres, anti-DNAse B titres or throat swab positivity for Group A streptococcus], and c) Low serum C3 levels, with normalization on 8 wk follow up. PIGN included PSGN and other infectious etiologies. AKI was classified as per Acute Kidney Injury Network (AKIN) criteria. Clinical features, biochemical and serological investigations in the study subjects were recorded.

RESULTS

Among 83 children with acute nephritic syndrome (ANS) recruited, 72 (86.7 %) had PIGN. PSGN was the most common etiology [65(90.3 %)] among the PIGN cases. Pyodermas, upper respiratory infections and varicella preceded hematuria in 58 (80.6 %), 4 (5.6 %) and 2 (2.8 %) cases respectively. Pneumonia, mumps and liver abscess caused PIGN in 7 (9.7 %) cases. Complications included AKI in 15 (20.8 %), hypertensive emergency in 14 (19.4 %), cardiac failure in 8 (11.1 %), encephalopathy in 3 (4.2 %) cases and retinopathy in 1 (1.4 %) case. Among the AKI patients, 3(20 %) were in AKI stage 3, while 1 child required hemodialysis. Twenty three cases (31.9 %) had evidence of residual renal injury at discharge. Renal biopsy showed diffuse proliferative glomerulonephritis in 4 and crescentic glomerulonephritis in one case of PIGN. At 6 mo follow up, one patient continued to have microalbuminuria.

CONCLUSIONS

PIGN (including PSGN) remains a significant contributor to morbidity in children with ANS. The study is notable for high incidence of hypertensive emergency and AKI, that often required intensive care management.

New trends of an old disease: the acute post infectious glomerulonephritis at the beginning of the new millenium

The association between acute renal disease and infection has been known since the mid '800s: acute post-infectious glomerulonephritis (PIGN) is a reactive immunological process against the kidney secondary to an infection, classically caused by a Streptococcus. The typical clinical presentation of PIGN is an acute nephritic syndrome with macro- or microscopic hematuria, proteinuria, hypertension, edema and renal function impairment of variable degree. The histology is characterized by an intracapillary glomerular proliferation, but may rarely be associated with an extracapillary proliferation. The classical childhood form is still present nowadays, even with severe cases, in developing countries, while in the last decades it almost disappeared in industrialized countries, where post-infectious GN are often found in elderly patients with multiple comorbidities. These clinical variants are usually related to other infective agents, like Staphylococcus aureus, both methicillin resistant (MRSA) and susceptible, and may be characterized by an IgA-dominant deposition. Kidney biopsy is rarely needed, especially in the child, while in the adult or old patient a biopsy is warranted if there is an atypical presentation or evolution, like rapidly progressive renal failure, absent or delayed function recovery, persisting low C3, nephrotic range proteinuria and persisting high proteinuria. Current therapy strategies rely on culture-guided systemic antibiotics, especially in the old patient, in which MRSA are relatively frequent, support therapy and only in very selected cases on steroids. These latter cases include the rare PIGN with crescents and those with a severe interstitial inflammation.

Prospective population-based study on the burden of disease from post-streptococcal glomerulonephritis of hospitalised children in New Zealand: epidemiology, clinical features and complications

AIM

A nationwide 24-month study was conducted (2007-2009), via the New Zealand Paediatric Surveillance Unit to define epidemiology and clinical features of acute poststreptococcal glomerulonephritis (APSGN) in children hospitalised with the illness.

METHODS

Paediatricians (n = 215) were requested to report new hospitalised cases fulfilling a case definition of definite (haematuria with low C3 and high streptococcal titres or biopsy proven APSGN) or probable (haematuria with low C3 or high streptococcal titres).

RESULTS

A total of 176 cases were identified (definite: n = 138, probable: n = 38) with 63% residing in the Auckland metropolitan region. Sixty-seven percent were in the most deprived quintile. Annual incidence (0-14 years) was 9.7/100,000 (Pacific 45.5, Maori 15.7, European/other 2.6 and Asian 2.1/100,000). Annual incidence was highest in the South Auckland Metropolitan region (31/100,000), Central Auckland 14.9, West/North Auckland metropolitan region 5.9 and for the remainder of New Zealand 5.5/100,000. Age-specific incidence was highest in age 5-9 years (15.1/100,000). Reduced serum complement C3, gross haematuria, hypertension, impairment of renal function and heavy proteinuria were present in 93%, 87%, 72%, 67% and 44% of patients, respectively. Severe hypertension was closely associated with either symptoms of an acute encephalopathy or congestive heart failure.

CONCLUSIONS

New Zealand children carry a significant disease burden of hospitalised APSGN with socio-economically deprived; Pacific and Maori children are being over-represented. Significant short-term complications were observed in hospitalised children with APSGN. Persistently very low rates in European/other suggest a preventable disease.

Post-streptococcal acute glomerulonephritis associated with pneumococcal infection

Streptococcus pyogenes is the most common cause of post-infectious glomerulonephritis. Described herein is the case of a 5-year-old girl with febrile post-streptococcal acute glomerulonephritis (PSAGN) associated with pneumococcal bacteremia. The chief complaints were fever and macrohematuria without respiratory symptoms. Urinalysis indicated a protein level of 3+. Serological data showed elevated anti-streptolysin O (ASO) and hypocomplementemia. Blood culture was positive for S. pneumoniae. Her acute renal failure was mild and improved over several days. Although PSAGN was confirmed by elevated ASO and transient hypocomplementemia, the clinical course was consistent with those of several reported cases of AGN associated with pneumococcal infection. To our knowledge, there have been few reports on the relationship between pneumococcal infection and the incidence of PSAGN. We suggest the hypothesis that pneumococcal infection itself could exaggerate the complement reaction leading to PSAGN. It is important to consider PSAGN associated with a microbial infection such as S. pneumoniae when faced with a febrile patient with AGN.

Posterior reversible encephalopathy syndrome in children with kidney diseases

Posterior reversible encephalopathy syndrome (PRES) was originally used to describe a reversible, predominantly posterior leukoencephalopathy in patients who had renal insufficiency, hypertension, or who received immunosuppressive therapy. Since PRES is prevalent in children with kidney diseases, awareness and understanding of it is important for practicing pediatric nephrologists. A comprehensive approach to the diagnosis of PRES includes thorough determination of predisposing factors, clinical symptoms, and mandatory appropriate imaging. Unfortunately, the pathophysiology of PRES is still obscure and specificity of radiological examination has not yet been established. Two major predisposing factors, namely hypertension and calcineurin inhibitors, are well recognized. In addition, nephrotic syndrome is a common underlying condition for development of PRES. Frequent symptoms include altered consciousness (coma, stupor, lethargy, confusion), seizure, headache, and visual disturbance. Most of these symptoms usually develop abruptly and resolve within a few weeks after proper management. Cranial magnetic resonance (MR) imaging is the first-line modality of imaging studies for detecting PRES. Diffusion-weighted imaging with quantification of apparent diffusion coefficient (ADC) values by ADC mapping may provide more accurate and specific images in the future.

Molecular insight into invasive group A streptococcal disease

Streptococcus pyogenes is also known as group A Streptococcus (GAS) and is an important human pathogen that causes considerable morbidity and mortality worldwide. The GAS serotype M1T1 clone is the most frequently isolated serotype from life-threatening invasive (at a sterile site) infections, such as streptococcal toxic shock-like syndrome and necrotizing fasciitis. Here, we describe the virulence factors and newly discovered molecular events that mediate the in vivo changes from non-invasive GAS serotype M1T1 to the invasive phenotype, and review the invasive-disease trigger for non-M1 GAS. Understanding the molecular basis and mechanism of initiation for streptococcal invasive disease may expedite the discovery of novel therapeutic targets for the treatment and control of severe invasive GAS diseases.

Post-streptococcal acute glomerulonephritis in children: clinical features and pathogenesis

Post-streptococcal acute glomerulonephritis (PSAGN) is one of the most important and intriguing conditions in the discipline of pediatric nephrology. Although the eventual outcome is excellent in most cases, PSAGN remains an important cause of acute renal failure and hospitalization for children in both developed and underdeveloped areas. The purpose of this review is to describe both the typical and less common clinical features of PSAGN, to outline the changes in the epidemiology of PSAGN over the past 50 years, and to explore studies on the pathogenesis of the condition with an emphasis on the search for the elusive nephritogenic antigen.

The incidence of primary glomerulonephritis worldwide: a systematic review of the literature

BACKGROUND

Little is known about the worldwide variation in incidence of primary glomerulonephritis (GN). The objective of this review was to critically appraise studies of incidence published in 1980-2010 so that an overall view of trends of these diseases can be found. This would provide important information for determining changes in rates and understanding variations between countries.

METHODS

All relevant papers found through searches of Medline, Embase and ScienceDirect were critically appraised and an assessment was made of the reliability of the reported incidence data.

RESULTS

This review includes 40 studies of incidence of primary GN from Europe, North and South America, Canada, Australasia and the Middle East. Rates for the individual types of disease were found to be in adults, 0.2/100,000/year for membrano-proliferative GN, 0.2/100,000/year for mesangio-proliferative GN, 0.6/100,000/year for minimal change disease, 0.8/100,000/year for focal segmental glomerulosclerosis, 1.2/100,000/year for membranous nephropathy and 2.5/100,000/year for IgA nephropathy. Rates were lower in children at around 0.1/100,000/year with the exception of minimal change disease where incidence was reported to be 2.0/100,000/year in Caucasian children with higher rates in Arabian children (9.2/100,000/year) and Asian children (6.2-15.6/100,000/year).

CONCLUSIONS

This study found that incidence rates of primary GN vary between 0.2/100,000/year and 2.5/100,000/year. The incidence of IgA nephropathy is at least 2.5/100,000/year in adults; this disease can exist subclinically and is therefore only detected by chance in some patients. In addition, referral policies for diagnostic biopsy vary between countries. This will affect the incidence rates found.