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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
    • renal disease secondary to an inflammatory process injuring the glomerulus
      • this results in damage involving the
        • basement membrane
        • capillary endothelium
        • mesangium
  • Presentation
    • symptoms
      • hypertension
      • hematuria
      • oliguria
      • headache
    • physical exam
      • edema
        • can be peripheral and/or periorbital
  • Diagnosis
    • studies
      • complete blood cell count
        • anemia may be noted
      • azotemia
      • complement levels
        • C3, C4, and CH50 should be obtained
      • urinalysis
        • dysmorphic red blood cells (RBCs)
          • suggests hematuria is of glomerular origin
        • RBC casts
        • subnephrotic range proteinuria (< 3.5 g/day)
          • if the nephritic syndrome is severe enough it can lead to nephrotic range proteinuria (> 3.5 g/day)
    • renal biopsy
      • may be necessary to arrive to a definitive diagnosis and to determine prognosis
 
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 positive 
  • 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
 
 

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