Nephritic Syndrome Workup

Suspect nephritic syndrome when hematuria accompanies proteinuria plus hypertension, edema, oliguria, or impaired kidney function. A rapidly progressive fall in kidney function with a nephritic urine picture is the clinical syndrome of rapidly progressive glomerulonephritis and should accelerate nephrology involvement and biopsy planning. ScienceDirect+2ScienceDirectNephritic Syndrome - an overview | ScienceDirect TopicsPubMedClinical Presentation & Management of Glomerular Diseases: Hematuria, Nephritic & Nephrotic Syndrome - PMCPubMedNephritic Syndrome - StatPearls - NCBI Bookshelf

At presentation, obtain blood pressure, weight, urine output history, serum creatinine, electrolytes, serum albumin, urinalysis with microscopy, and quantitative protein excretion. These data separate an inflammatory glomerular process from isolated nonglomerular hematuria, define the severity of kidney dysfunction, and identify mixed nephritic-nephrotic presentations that occur with disorders such as membranoproliferative GN. PubMed+1PubMedA beginner’s guide to the clinical approach and key concepts of glomerular disease: a mini reviewPubMedClinical Presentation & Management of Glomerular Diseases: Hematuria, Nephritic & Nephrotic Syndrome - PMC

Review the time course and systemic clues before interpreting serologies. Recent or ongoing infection supports infection-related GN; episodic flares are characteristic of IgA nephropathy and C3 glomerulopathy; pulmonary hemorrhage or rapidly progressive GN raises concern for anti-GBM disease; and systemic autoimmune features should prompt evaluation for lupus or ANCA-associated vasculitis. ScienceDirect+1ScienceDirectAcute glomerulonephritis - ScienceDirectPubMedNephritic Syndrome - StatPearls - NCBI Bookshelf

Request fresh urine microscopy with explicit assessment for RBC morphology, acanthocytes, RBC casts, WBC casts, renal tubular epithelial cells, and renal tubular epithelial cell casts. A reasonable definition of glomerular hematuria is at least 40% dysmorphic RBCs, at least 5% acanthocytes, or at least 1 RBC cast per 50 low-power fields. PubMedPubMedDiagnostic Utility of Urine Microscopy in Kidney Diseases

A lower dysmorphic-RBC cutoff of at least 25% had sensitivity of 20.4% and specificity of 96.3% for glomerular disease in one study; therefore, a negative or weakly positive dysmorphic-RBC assessment does not exclude GN. Isomorphic RBCs may occur in GN and also in acute interstitial nephritis, renal cell carcinoma, nephrolithiasis, urinary tract infection, and excessive anticoagulation. PubMedPubMedDiagnostic Utility of Urine Microscopy in Kidney Diseases

Interpret pyuria in context. WBC casts or pyuria together with dysmorphic RBCs or RBC casts favor proliferative GN, whereas tubular epithelial cells and casts may reflect concurrent tubular injury in acute nephritic syndrome. PubMedPubMedDiagnostic Utility of Urine Microscopy in Kidney Diseases

Obtain C3 and C4 before kidney biopsy whenever feasible. Hypocomplementemia directs the differential toward immune-complex and complement-mediated GN, including infection-related GN, lupus nephritis, cryoglobulinemic GN, and C3 glomerulopathy. Normal complement is more typical of anti-GBM disease, pauci-immune GN, and monoclonal immunoglobulin-associated GN, although monoclonal immunoglobulin disease can occasionally be hypocomplementemic and mimic C3 GN. ScienceDirect+2ScienceDirectAcute glomerulonephritis - ScienceDirectPubMedNephritic Syndrome - StatPearls - NCBI BookshelfPubMedA beginner’s guide to the clinical approach and key concepts of glomerular disease: a mini review

Order ANA and anti-dsDNA antibodies when lupus is plausible clinically or when complement is low. Order ANCA when pauci-immune vasculitis is possible, particularly with rapidly progressive kidney dysfunction or systemic vasculitic manifestations. Order circulating anti-GBM antibodies immediately when rapidly progressive GN or alveolar hemorrhage is present. ScienceDirect+2ScienceDirectAcute glomerulonephritis - ScienceDirectWolters KluwerPOSTER PRESENTATION : Indian Journal of NephrologyPubMedNephritic Syndrome - StatPearls - NCBI Bookshelf

For a possible poststreptococcal process, measure antistreptolysin O and anti-DNase B titers; elevated levels support recent streptococcal infection. In suspected infection-related GN, evaluate for active infection, including infective endocarditis when the clinical setting supports it, because both poststreptococcal disease and endocarditis-associated GN can have low complement. PubMedPubMedNephritic Syndrome - StatPearls - NCBI Bookshelf

Kidney biopsy is the gold standard for diagnosing glomerular diseases and is generally necessary in nephritic syndrome because proliferative patterns have a broad differential and overlapping clinical presentations. ScienceDirect+1ScienceDirectNephritic Syndrome - an overview | ScienceDirect TopicsWolters KluwerThe Cleveland Clinic Kidney Biopsy Epidemiological Project Expedite biopsy when kidney function is rapidly declining, the sediment is active with RBC casts, serologies suggest anti-GBM disease or ANCA-associated vasculitis, or the presentation combines nephritic and nephrotic features. ScienceDirect+2ScienceDirectAcute glomerulonephritis - ScienceDirectScienceDirectNephritic Syndrome - an overview | ScienceDirect TopicsPubMedClinical Presentation & Management of Glomerular Diseases: Hematuria, Nephritic & Nephrotic Syndrome - PMC

Request interpretation integrating light microscopy, immunofluorescence, and clinical serologies. Immunofluorescence patterns help infer etiology: immune-complex GN includes infection-related GN, IgA nephropathy, lupus nephritis, and cryoglobulinemic GN; pauci-immune GN is associated with ANCA vasculitis; anti-GBM disease shows linear IgG deposition along the GBM; and C3 glomerulopathy is complement mediated. ScienceDirect+1ScienceDirectAcute glomerulonephritis - ScienceDirectWolters KluwerPOSTER PRESENTATION : Indian Journal of Nephrology

Do not rely on a single histologic label without etiologic correlation. MPGN and diffuse proliferative GN are patterns of injury that can arise from infection, lupus, cryoglobulinemia, hepatitis C, complement dysregulation, or monoclonal immunoglobulin disease. The pathology report should therefore be reconciled with complement studies, infection assessment, autoimmune serologies, and monoclonal-protein evaluation when indicated by the biopsy pattern. ScienceDirect+1ScienceDirectAcute glomerulonephritis - ScienceDirectPubMedA beginner’s guide to the clinical approach and key concepts of glomerular disease: a mini review

Manage clinically significant hypertension, edema, oliguria, and deteriorating kidney function in parallel with the diagnostic evaluation. Nephritic syndrome is associated with salt-water retention, hypertension, edema, and reduced kidney function; reassess blood pressure, body weight, urine output, serum creatinine, and electrolytes as the clinical course evolves. ScienceDirect+2ScienceDirectNephritic Syndrome - an overview | ScienceDirect TopicsPubMedA beginner’s guide to the clinical approach and key concepts of glomerular disease: a mini reviewPubMedClinical Presentation & Management of Glomerular Diseases: Hematuria, Nephritic & Nephrotic Syndrome - PMC

Avoid treating all edema as equivalent. Nephrotic physiology can be associated with either intravascular underfilling from albumin loss or overfill from increased tubular sodium absorption; determine volume status before using therapies intended to remove fluid. PubMedPubMedMinimal Change Disease - StatPearls - NCBI Bookshelf When nephrotic-range proteinuria coexists, serum albumin below 3.0 g/dL with protein excretion above 3.0 g per 24 hours supports nephrotic syndrome and should prompt assessment for thrombotic manifestations. PubMed+1PubMedClinical Presentation & Management of Glomerular Diseases: Hematuria, Nephritic & Nephrotic Syndrome - PMCPubMedClinical presentation & management of glomerular diseases: hematuria, nephritic & nephrotic syndrome. - Abstract

Escalate rapidly when renal function declines over days to weeks, urine output falls, RBC casts persist, or pulmonary hemorrhage is suspected. These features shift the working diagnosis toward crescentic processes such as ANCA-associated or anti-GBM GN and justify urgent nephrology-led biopsy and treatment decisions. ScienceDirect+2ScienceDirectAcute glomerulonephritis - ScienceDirectWolters KluwerPOSTER PRESENTATION : Indian Journal of NephrologyPubMedClinical Presentation & Management of Glomerular Diseases: Hematuria, Nephritic & Nephrotic Syndrome - PMC