Nephritic Syndrome

Treat nephritic syndrome with rising creatinine, oliguria, active urine sediment, or suspected crescentic glomerulonephritis as a nephrologic emergency. Rapidly progressive glomerulonephritis (RPGN) is most often associated with anti-GBM disease, ANCA-associated vasculitis (AAV), or immune-complex glomerulonephritis. ScienceDirect+1ScienceDirectRapidly Progressive Glomerulonephritis - ScienceDirectPubMedEvidence-based clinical practice guidelines for rapidly progressive glomerulonephritis 2014 - PMC

When acute kidney injury coexists with alveolar hemorrhage or otherwise unexplained simultaneous pulmonary and kidney injury, use a pulmonary-renal framework: obtain anti-GBM antibody and MPO- and PR3-ANCA testing urgently, assess for diffuse alveolar hemorrhage, and arrange nephrology-directed tissue diagnosis. A positive anti-GBM antibody result warrants urgent plasma exchange without waiting for biopsy. Kidney International+1Kidney InternationalKDIGO 2024 Clinical Practice Guideline for the Management of Antineutrophil Cytoplasmic Antibody (ANCA)–Associated VasculitisKidney InternationalKDIGO 2021 Clinical Practice Guideline for the ...

Do not use a positive ANCA result as a substitute for clinicopathologic diagnosis. ANCA supports AAV in the appropriate syndrome, but anti-GBM/ANCA double positivity occurs, and renal pathology can demonstrate overlapping immune-complex and necrotizing lesions. Kidney International+2Kidney InternationalKDIGO 2024 Clinical Practice Guideline for the Management of Antineutrophil Cytoplasmic Antibody (ANCA)–Associated Vasculitisasn-onlineAmerican Society of Nephrology | Kidney Week - Abstract Details (2019)WileyANCA‐Associated Necrotizing Glomerulonephritis Overlapping with Mesangial Proliferative Lupus Nephritis Refractory to Plasmapheresis, Steroid Pulse Therapy, and a Combination of Mycophenolate Mofetil and Rituximab - Sharmeen - 2018 - Case Reports in Rheumatology - Wiley Online Library

Confirm that hematuria is glomerular before pursuing a broad vasculitis workup. Red cell casts are virtually pathognomonic for glomerular pathology. Acanthocytes are associated with glomerular disease, whereas the broader category of dysmorphic erythrocytes is less specific and requires fresh urine examined by experienced personnel. BMJBMJAssessment and management of non-visible haematuria in primary ...

Obtain serum creatinine, quantitative proteinuria, urinalysis with microscopy, and targeted serologies that separate anti-GBM disease, AAV, lupus nephritis, infection-related disease, cryoglobulinemic disease, complement-mediated disease, and monoclonal immunoglobulin-associated glomerulonephritis. The central etiologic categories are immune-complex GN, pauci-immune/ANCA-associated GN, anti-GBM GN, C3 glomerulopathy, and monoclonal immunoglobulin-associated GN. ScienceDirect+2ScienceDirectAcute glomerulonephritis - ScienceDirectScienceDirectAcute glomerulonephritisKidney InternationalKDIGO 2024 Clinical Practice Guideline for the Management of Antineutrophil Cytoplasmic Antibody (ANCA)–Associated Vasculitis

Use the clinical setting to prioritize testing. Acute nephritic or RPGN presentations are particularly associated with post-infectious GN, AAV, and anti-GBM disease; episodic flares are characteristic of IgA nephropathy and C3 glomerulopathy. ScienceDirectScienceDirectAcute glomerulonephritis - ScienceDirect In a patient with concurrent infection and glomerular injury, determine whether infection is active before initiating immunosuppression, particularly with Staphylococcus-associated IgA-dominant infection-related GN. community asn-onlinecommunity asn-onlineCommunity Minded - ASN Community

Interpret light microscopy together with immunofluorescence and electron microscopy when available. The same histologic pattern can arise from different mechanisms: an MPGN pattern may reflect hepatitis C-associated immune-complex disease or alternative-complement pathway abnormalities, while diffuse proliferative GN can result from infection, lupus, or cryoglobulinemia. ScienceDirectScienceDirectAcute glomerulonephritis - ScienceDirect Therefore, select treatment based on the causal category rather than the descriptive biopsy pattern alone. ScienceDirectScienceDirectAcute glomerulonephritis

For pauci-immune/ANCA-associated RPGN, glucocorticoids combined with cyclophosphamide or rituximab are standard treatment options; plasma exchange has a more selective role than in anti-GBM disease. ScienceDirectScienceDirectRapidly Progressive Glomerulonephritis - ScienceDirect Biopsy remains valuable even with a positive ANCA because kidney histology predicts long-term kidney-failure risk and supports histopathologic prognostic classification. Kidney InternationalKidney InternationalKDIGO 2024 Clinical Practice Guideline for the Management of Antineutrophil Cytoplasmic Antibody (ANCA)–Associated Vasculitis

For anti-GBM disease, combine urgent plasma exchange with corticosteroids and immunosuppressive therapy in the RPGN presentation. PubMedPubMedEvidence-based clinical practice guidelines for rapidly progressive glomerulonephritis 2014 - PMC Check ANCA concurrently because a meaningful subset of anti-GBM nephritis cases are double positive, which may affect diagnostic interpretation and longer-term disease assessment. Kidney International+1Kidney InternationalKDIGO 2024 Clinical Practice Guideline for the Management of Antineutrophil Cytoplasmic Antibody (ANCA)–Associated Vasculitisasn-onlineAmerican Society of Nephrology | Kidney Week - Abstract Details (2019)

For infection-related GN, control the infection and confirm the diagnosis pathologically when the renal course is severe or atypical. In Staphylococcus bacteremia with IgA-dominant infection-related GN, corticosteroid use after antimicrobial response remains debated; immunosuppression can add serious infection risk. community asn-onlinecommunity asn-onlineCommunity Minded - ASN Community

Track serial serum creatinine, urine output, urine sediment, and quantitative proteinuria during acute management. Persistent or worsening kidney injury despite appropriate infection control, anti-GBM-directed therapy, or AAV induction should prompt review of biopsy adequacy, immunofluorescence findings, competing acute tubular injury, obstructive disease, medication exposures, and a second glomerular process. Mixed immune-complex and pauci-immune lesions are documented in lupus nephritis and IgA nephropathy. Wiley+1WileyANCA‐Associated Necrotizing Glomerulonephritis Overlapping with Mesangial Proliferative Lupus Nephritis Refractory to Plasmapheresis, Steroid Pulse Therapy, and a Combination of Mycophenolate Mofetil and Rituximab - Sharmeen - 2018 - Case Reports in Rheumatology - Wiley Online Libraryasn-onlineAmerican Society of Nephrology | Kidney Week - Abstract Details (2024)

In AAV, use kidney histology as part of longer-term prognostic counseling because histopathologic classifications based on glomerular lesions predict risk of kidney failure. Kidney InternationalKidney InternationalKDIGO 2024 Clinical Practice Guideline for the Management of Antineutrophil Cytoplasmic Antibody (ANCA)–Associated Vasculitis Clinical remission assessment must distinguish active vasculitic GN from chronic scarring, since escalating immunosuppression for irreversible damage increases toxicity without restoring renal function. Kidney InternationalKidney InternationalKDIGO 2024 Clinical Practice Guideline for the Management of Antineutrophil Cytoplasmic Antibody (ANCA)–Associated Vasculitis

For hematuria without kidney-function decline or significant proteinuria, avoid assuming all non-visible hematuria is nephritic syndrome. In patients younger than 40 years with asymptomatic non-visible hematuria, renal causes such as IgA nephropathy and thin basement membrane disease are more likely than urologic disease, and urologic referral is not routinely necessary solely on that basis. BMJBMJAssessment and management of non-visible haematuria in primary ...