Glomerulonephritis Diagnosis and Treatment

Initial Diagnostic Approach

The workup for suspected glomerulonephritis requires urgent urinalysis with microscopy, autoimmune serologies, and kidney biopsy when feasible, while treatment should not be delayed if clinical presentation and serology strongly suggest rapidly progressive disease 1
Assess for rapidly progressive glomerulonephritis warning signs: rapid decline in kidney function, oliguria, severe hypertension, and pulmonary hemorrhage 1

Perform urine dipstick for protein and blood, followed by microscopic examination for glomerular hematuria and red blood cell casts 1, 2
Quantify proteinuria using 24-hour urine collection in adults; first morning protein-creatinine ratio is more appropriate in children 2

Kidney biopsy remains the gold standard for diagnosis and should be performed when feasible to confirm diagnosis and provide prognostic information 1, 2
If clinical presentation is compatible with ANCA vasculitis and MPO- or PR3-ANCA is positive, do not delay starting immunosuppressive therapy while waiting for biopsy 1

For ANCA-associated vasculitis, use cyclophosphamide plus corticosteroids or rituximab plus corticosteroids as initial treatment 3, 4
For lupus nephritis, use corticosteroids combined with either cyclophosphamide or mycophenolate mofetil for initial therapy 5
For membranous nephropathy, consider observation for 6 months before initiating immunosuppression unless severe symptoms or declining kidney function are present 5

Screen for latent infections and review vaccination status before starting immunosuppression 2, 6
Monitor therapeutic drug levels and development of cancers or infections during therapy 2, 6

Assess proteinuria regularly, as reduction in proteinuria is a key marker of treatment response 6, 7
Monitor for decline in eGFR from baseline over 2-3 years as a surrogate outcome for kidney failure 6, 7

The American Society of Nephrology recommends measuring blood pressure carefully, as hypertension is a cardinal feature of nephritic syndrome and predicts progression, with target BP goals varying by proteinuria level (≤130/80 mmHg if proteinuria <1 g/day; ≤125/75 mmHg if >1 g/day) 8
Documenting temperature is crucial to identify infection-related glomerulonephritis or complications from immunosuppression, according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines 9

Calculating BMI is essential, as obesity can contribute to hyperfiltration injury in secondary forms of glomerulonephritis, as stated by the National Kidney Foundation 10

Auscultating for new or changed cardiac murmurs is necessary to identify endocarditis-associated glomerulonephritis, as recommended by the American Heart Association 9

Examining skin for characteristic lesions, including purpura, malar rash, or active impetigo/cellulitis, is vital in diagnosing infection-related glomerulonephritis, according to the European Renal Association 9

Palpating for splenomegaly may indicate endocarditis-associated glomerulonephritis, as suggested by the Infectious Diseases Society of America 9