Snapshot A 26-year-old man presents with hematuria, periorbital edema, and jaundice. He has a medical history of opioid use disorder with prior hospitalizations for heroin overdose. He is on methadone but is non-adherent. His blood pressure is 155/102 mmHg. Physical examination is significant for scleral icterus, hepatomegaly, and palpable purpura. Serology shows decreased C3 and C4 levels and elevated anti-hepatitis C antibodies. Urinalysis demostrates dysmorphic red blood cells and red blood cell casts. (Membranoproliferative glomerulonephritis) Introduction Clinical definition login to view 5 more bullets Presentation login to view 8 more bullets Diagnosis login to view 14 more bullets Nephritic Syndrome Type Pathophysiology Renal Biopsy Diagnostic Studies and Treatment Acute poststreptococcal glomerulonephritis Glomerulonephritis secondary to nephritogenic strains of streptococcus - type III hypersensitivity reaction Light microscopy - glomerular hypercellularity e.g., polymorphonuclear leukocytes Immunofluoresence - diffuse granular pattern on glomerular capillary and mesangium deposition of IgG, IgM, and C3 Electron microscopy - electron-dense, glomerular subepithelial immune-complex deposits ("humps") Streptococcus titers and serologies are positive e.g., ASO levels ↓ serum C3 levels Typically self-resolves Rapidly progressive glomerulonephritis Goodpasture syndrome - type II hypersensitivity - anti-GBM antibodies against α3-chain of collagen type IV - antibodies to the alveolar basement membrane result in hemoptysis and lung disease Pauci-immune processes - granulomatosis with polyangiitis - microscopic polyangiitis Light microscopy and immunofluoresence - crescent-shaped deposition of fibrin, C3b, glomerular parietal cells, monocytes, and macrophages Granulomatosis with polyangiitis - PR3-ANCA/c-ANCA Microscopic polyangiitis - MPO-ANCA/p-ANCA Corticosteroids and cyclophosphamide IgA nephropathy (Berger disease) IgA immune-complex deposition in glomerular mesangial cells that results in its proliferation - patients present with hematuria and upper respiratory tract or gastrointenstinal infection Light microscopy - mesangial proliferation Immunofluoresence - IgA immune-complex deposition in the mesangium ACE inhibitor or ARB for proteinuria and hypertension Alport syndrome Collagen type IV mutation that results in an abnormal basement membrane - more commonly an X-linked genetic disorder characterized by: renal involvement ocular involvement sensorineural hearing loss Electron microscopy - glomerular basement membrane lamellation No curative treatment Membranoproliferative glomerulonephritis (MPGN) Immune-complex and/or complement protein deposition in the mesangium and subendothelium of the capillaries - this results in proliferation of the mesangium and remodeling of the capillary wall - may be secondary to hepatitis C virus hepatitis B virus C3 nephritic factor MPGN type II Can also present as a nephrotic syndrome Light microscopy - mesangial proliferation and thickening of the capillary wall Immunofluoresence - "tram-track" appearance ↓ serum C3 and C4 levels - Treat underlying disease in secondary causes e.g., control of hepatitis C virus infection