Nephritic Syndrome Diagnosis

Nephritic Syndrome

Infection-Associated Glomerulonephritis

• Glomerular enlargement and hypercellularity are observed under Light Microscopy (LM)
• No immunofluorescence is detected
• Electron Microscopy (EM) reveals a granular (“starry sky”) appearance due to IgG, IgM, and C3 deposition along the glomerular basement membrane (GBM) and mesangium
• Sub-epithelial IC humps are seen under Infrared Microscopy (IF)
• Hypocomplementemia is observed in the CH50 Assay (total haemolytic complement)

IgA Nephropathy (Berger Disease)

• Mesangial proliferation is observed under Light Microscopy
• Mesangial IgA deposits are detected by Immunofluorescence
• Mesangial IC deposits are seen under Electron Microscopy
• Nephritic sediment is observed in Urinalysis

Rapidly Progressive Glomerulonephritis

• Crescent-shaped deposits in glomeruli are observed under Light Microscopy (LM)
• Crescents consist of fibrin and plasma proteins (eg, C3b) with glomerular parietal cells, monocytes, and macrophages
• Three types of Rapidly Progressive Glomerulonephritis are classified based on Immunofluorescence:
  • Type 1: Linear immunofluorescence, associated with Goodpasture syndrome (hemoptysis/hematuria), IgG and C3 deposits along GBM, and ANCA negative
  • Type 2: Granulomatosis with polyangiitis, no immunofluorescence, no deposits in GBM, granular “lumpy bumpy” GBM deposits, autoantibodies against the proteinase-3 enzyme in neutrophils (PR3), and C-ANCA
  • Type 3: Microscopic Polyangiitis (Myeloperoxidase Antineutrophil Cytoplasmic Antibodies (MP0-ANCA), eosinophilic granulomatosis with polyangiitis, no immunofluorescence, no deposits in GBM, and P-ANCA

Goodpasture Syndrome

• Cellular accumulation in Bowman space and crescent formations are observed under Light Microscopy (LM)
• IgG deposits along GBM are detected by Immunofluorescence
• C3 levels are normal, and ANCA is negative
• Renal Biopsy is the gold standard for diagnosis
• Differential diagnosis includes granulomatosis with polyangiitis, which presents with necrotizing glomerulonephritis and affects the upper respiratory tract

Diffuse Proliferative Glomerulonephritis (DPG)

• Capillary loop thickening and “wire loops” are observed under Light Microscopy (LM)
• Granular appearance is observed by Immunofluorescence
• Electron Microscopy shows IgG-based ICs often with C3 deposition, which can be subendothelial, subepithelial, or intramembranous

Alport Syndrome

• Irregular thinning, thickening, and splitting of the glomerular basement membrane are observed under Light Microscope
• Immunofluorescence is initially negative, but IgG, IgM, and/or C3 may be observed later
• Electron Microscopy reveals a “basket-weave” appearance due to irregular thickening and longitudinal splitting of GBM

Infection-Associated Glomerulonephritis

• Glomerular enlargement and hypercellularity observed under Light Microscopy (LM)
• No immunofluorescence detected
• Electron Microscopy (EM) reveals granular (“starry sky”) appearance due to IgG, IgM, and C3 deposition along glomerular basement membrane (GBM) and mesangium
• Sub-epithelial IC humps seen under Infrared Microscopy (IF)
• Hypocomplementemia observed in the CH50 Assay (total haemolytic complement)

IgA Nephropathy (Berger Disease)

• Mesangial proliferation observed under Light Microscopy
• Mesangial IgA deposits detected by Immunofluorescence
• Mesangial IC deposits seen under Electron Microscopy
• Nephritic sediment observed in Urinalysis

Rapidly Progressive Glomerulonephritis

• Crescent-shaped deposits in glomeruli observed under Light Microscopy (LM)
• Crescents consist of fibrin and plasma proteins (e.g., C3b) with glomerular parietal cells, monocytes, and macrophages
• Three types of Rapidly Progressive Glomerulonephritis classified based on Immunofluorescence:
  • Type 1: Linear immunofluorescence, associated with Goodpasture syndrome, IgG and C3 deposits along GBM, and ANCA negative
  • Type 2: Granulomatosis with polyangiitis, no immunofluorescence, no deposits in GBM, granular “lumpy bumpy” GBM deposits, autoantibodies against proteinase-3 enzyme in neutrophils (PR3), and C-ANCA
  • Type 3: Microscopic Polyangiitis (Myeloperoxidase Antineutrophil Cytoplasmic Antibodies (MP0-ANCA), eosinophilic granulomatosis with polyangiitis, no immunofluorescence, no deposits in GBM, and P-ANCA

Goodpasture Syndrome

• Cellular accumulation in Bowman space and crescent formations observed under Light Microscopy (LM)
• IgG deposits along GBM detected by Immunofluorescence
• C3 levels normal, and ANCA negative
• Renal Biopsy is the gold standard for diagnosis
• Differential diagnosis includes granulomatosis with polyangiitis, which presents with necrotizing glomerulonephritis and affects the upper respiratory tract

Diffuse Proliferative Glomerulonephritis (DPG)

• Capillary loop thickening and “wire loops” observed under Light Microscopy (LM)
• Granular appearance observed by Immunofluorescence
• Electron Microscopy shows IgG-based ICs often with C3 deposition, which can be subendothelial, subepithelial, or intramembranous

Alport Syndrome

• Irregular thinning, thickening, and splitting of the glomerular basement membrane observed under Light Microscope
• Immunofluorescence initially negative, but IgG, IgM, and/or C3 may be observed later
• Electron Microscopy reveals a “basket-weave” appearance due to irregular thickening and longitudinal splitting of GBM

Infection-Associated Glomerulonephritis

• Glomerular enlargement and hypercellularity observed under Light Microscopy (LM)
• No immunofluorescence detected
• Electron Microscopy (EM) reveals granular (“starry sky”) appearance due to IgG, IgM, and C3 deposition along glomerular basement membrane (GBM) and mesangium
• Sub-epithelial IC humps seen under Infrared Microscopy (IF)
• Hypocomplementemia observed in the CH50 Assay (total haemolytic complement)

IgA Nephropathy (Berger Disease)

• Mesangial proliferation observed under Light Microscopy
• Mesangial IgA deposits detected by Immunofluorescence
• Mesangial IC deposits seen under Electron Microscopy
• Nephritic sediment observed in Urinalysis

Rapidly Progressive Glomerulonephritis

• Crescent-shaped deposits in glomeruli observed under Light Microscopy (LM)
• Crescents consist of fibrin and plasma proteins (e.g., C3b) with glomerular parietal cells, monocytes, and macrophages
• Three types of Rapidly Progressive Glomerulonephritis classified based on Immunofluorescence:
  • Type 1: Linear immunofluorescence, associated with Goodpasture syndrome, IgG and C3 deposits along GBM, and ANCA negative
  • Type 2: Granulomatosis with polyangiitis, no immunofluorescence, no deposits in GBM, granular “lumpy bumpy” GBM deposits, autoantibodies against proteinase-3 enzyme in neutrophils (PR3), and C-ANCA
  • Type 3: Microscopic Polyangiitis (Myeloperoxidase Antineutrophil Cytoplasmic Antibodies (MP0-ANCA), eosinophilic granulomatosis with polyangiitis, no immunofluorescence, no deposits in GBM, and P-ANCA

Goodpasture Syndrome

• Cellular accumulation in Bowman space and crescent formations observed under Light Microscopy (LM)
• IgG deposits along GBM detected by Immunofluorescence
• C3 levels normal, and ANCA negative
• Renal Biopsy is the gold standard for diagnosis
• Differential diagnosis includes granulomatosis with polyangiitis, which presents with necrotizing glomerulonephritis and affects the upper respiratory tract

Diffuse Proliferative Glomerulonephritis (DPG)

• Capillary loop thickening and “wire loops” observed under Light Microscopy (LM)
• Granular appearance observed by Immunofluorescence
• Electron Microscopy shows IgG-based ICs often with C3 deposition, which can be subendothelial, subepithelial, or intramembranous

Alport Syndrome

• Irregular thinning, thickening, and splitting of the glomerular basement membrane observed under Light Microscope
• Immunofluorescence initially negative, but IgG, IgM, and/or C3 may be observed later
• Electron Microscopy reveals a “basket-weave” appearance due to irregular thickening and longitudinal splitting of GBM