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Snapshot
  • A 14-year-old boy presents with hematuria, problems with vision, and deafness. Approximately 2 weeks prior to symptom development, he recovered from a viral upper respiratory tract infection. Family history is significant for deafness and early initiation of lisinopril in his father. His temperature is 99°F (37.2°C), blood pressure is 140/90 mmHg, pulse is 75/min, and respirations are 18/min. Physical examination is signifcant for anterior lenticonus and sensorineural hearing loss. Urinalysis demonstrates dysmorphic red blood cells and red blood cell casts. (Alport syndrome)
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 
  • Immunofluorescence
    • diffuse granular pattern on glomerular capillary walls and mesangium
      • deposition of IgG, IgM, and C3
  • Electron microscopy  
    • electron-dense, glomerular subepithelial immune-complex deposits ("humps")
  • Streptococcus titers and serologies are positive
  • ↓ 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 immunofluorescence
    • 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's disease)
  • IgA immune-complex deposition in glomerular mesangial cells that results in its proliferation
    • patients present with hematuria and upper respiratory tract or gastrointestinal infection
  • Light microscopy
    • mesangial proliferation
  • Immunofluorescence
    • 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 dominant disorder 
    • characterized by
      • renal involvement
      • ocular involvement
      • sensorineural hearing loss
  • Electron microscopy
    • glomerular basement membrane lamellation
    • "basket weave" appearance
  • 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
  • Light microscopy
    • mesangial proliferation and thickening of the capillary wall
  • Immunofluorescence
    • "tram-track" appearance
  • ↓ serum C3 and C4 levels
  • Treat underlying disease in secondary causes
    • e.g., control of hepatitis C virus infection
Diffuse proliferative glomerulonephritis (DPGN)
  • > 50% of glomeruli (thus diffuse) demonstrates an inflammatory process on histology
  • Common in patients with systemic inflammatory diseases (e.g., systemic lupus erythematosus)
    • can be secondary to membranoproliferative glomerulonephritis
  • Light microscopy
    • capillary "wire-looping"
  • Electron microscopy
    • immune complex deposition affecting the
      • subendothelial region
      • maybe intramembranous
  • Immunofluorescence
    • granular appearance
  • Can lead to death in patients with systemic lupus erythematosus
  • Aggressively treat with steroids
 
 

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