Clinicopathological features and prognosis of Chinese patients with acute post-streptococcal glomerulonephritis

An updated approach to the evaluation of the urinary sediment

Examination of the urinary sediment (U-sed) is an important non-invasive, rapid, and inexpensive tool for the diagnosis and surveillance over time of renal diseases. In this Educational Review, we describe first how to collect, prepare, and examine urine samples in order to obtain reliable results. Then, we describe the U-sed findings in isolated microscopic hematuria, glomerular diseases, acute interstitial nephritis, acute kidney injury, reactivation of the BK virus in kidney transplant recipients, and crystalluric genetic diseases.

Mechanisms that potentially contribute to the development of post-streptococcal glomerulonephritis

Post-streptococcal glomerulonephritis (PSGN) is primarily associated with preceding group A streptococcal skin or throat infections, now mainly observed in economically disadvantaged communities. This condition significantly predisposes individuals to later-life chronic kidney disease and concurrent renal complications, with the elderly experiencing increased severity and less favourable outcomes. Streptococcal pyrogenic exotoxin B and nephritis-associated plasmin receptor are identified nephritogenic antigens (nephritogens). Pathogenesis of PSGN is multifactorial. It can involve the formation of antigen-antibody immune complexes, causing inflammatory damage to renal glomeruli. Deposition of circulating immune complexes or in situ formation of immune complexes in glomeruli, or both, results in glomerulonephritis. Additionally, molecular mimicry is hypothesized as a mechanism, wherein cross-reactivity between anti-streptococcal antibodies and glomerular intrinsic matrix proteins leads to glomerulonephritis. Besides, as observed in clinical studies, streptococcal inhibitor of complement, a streptococcal-secreted protein, can also be associated with PSGN. However, the interplay between these streptococcal antigens in the pathogenesis of PSGN necessitates further investigation. Despite the clinical significance of PSGN, the lack of credible animal models poses challenges in understanding the association between streptococcal antigens and the disease process. This review outlines the postulated mechanisms implicated in the development of PSGN with possible therapeutic approaches.

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.

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

BACKGROUND

Rapidly progressive glomerulonephritis (RPGN), defined as acute nephritic syndrome with dramatic loss of renal function within a few months, is associated with crescentic glomerulonephritis (CresGN), which requires ≥50% crescents on pathology. The disease characteristics and renal outcome in children with RPGN, however, will differ according to the percentage of crescents.

METHODS

To evaluate the renal outcomes and factors associated with end-stage renal disease (ESRD), this retrospective cohort study assessed children aged ≤15 years with RPGN at a tertiary medical center.

RESULTS

Of 67 patients with RPGN, 32 (47.8%) were male; mean age was 10.6 ± 3.0 years; median follow up was 1.1 years (range, 0.02-9.17 years) and 24 (35.8%) progressed to ESRD. Post-infectious glomerulonephritis was the most frequent cause of RPGN (50.7%). The incidence of ESRD was significantly higher in patients with ≥50% than <50% crescents (57.9% vs 28.6%, P = 0.029). On Cox regression analysis, disease etiology, serum creatinine >3 mg/dL, need for acute dialysis, ≥80% crescents and ≥20% tubular atrophy and interstitial fibrosis (TA/IF) were associated with ESRD. On multivariate analysis, need for acute dialysis (HR, 2.8; 95% CI: 1.1-7.3, P = 0.041) and ≥20% TA/IF (HR, 4.8; 95% CI: 1.4-16.1, P = 0.011) were independent risk factors for the development of ESRD.

CONCLUSIONS

Approximately one-third of children with RPGN developed ESRD; and need for acute dialysis and TA/IF ≥20% were independent risk factors for ESRD.