Nephritic Syndrome

Features

  • Rapid onset
  • Hypertension
  • AKI
  • Mild proteinuria (2+ on dipstick, <3.5 g/day)
  • Glomerular hematuria (RBC casts, dysmorphie RBCs)

Approach

  • UA with microscopy to evaluate for proteinuria/hematuria, as well as dysmorphic RBCs or RBC casts
  • C3/C4 levels within normal limits
    • pANCA positive (Anti-myeloperoxidase, perinuclear, or Anti-MPO Antibody) (see Small Vessel Vasculitis)
      • Eosinophilic granulomatosis with polyangiitis (EGPA, formerly Churg-Strauss)
        • Associated with asthma, chronic rhinosinusitis
        • Peripheral eosinophilia
      • Microscopic polyangiitis (MPA)
        • May have associated sinusitis or other ENT symptoms
        • Associated with mononeuritis multiplex
    • c-ANCA positive (Anti-proteinase 3, or Anti-PR3 Antibody)
      • Granulomatosis with polyangiitis (GPA, formerly Wegener’s)
        • Inflammation of upper and lower airway, may have associated cough, sinusitis, or shortness of breath
        • Associated with mononeuritis multiplex
    • ANCA-negative
      • IgA Nephropathy
        • Classically presents after a viral upper respiratory infection or physical exertion
      • IgA Vasculitis (Henoch-Schonlein Purpura)
        • Classically presents in children and includes abdominal pain, leukocytoclastic vasculitis, and arthralgias. May also present after an acute viral upper respiratory infection
      • Anti-GBM disease
        • Goodpasture’s Syndrome if associated with pulmonary hemorrhage
  • C3/C4 levels below normal limits
    • Post-streptococcal glomerulonephritis
      • ~1-3 weeks after Group A streptococcal illness (skin or pharynx)
      • Diagnosis (1):
        • Anti-Streptolysin O (ASO) serology
        • Streptozyme: includes anti-nicotinamide-adenine dinucleotidase (anti-NAD), anti-DNAse B, and anti-hyaluronidase (AHase). Most sensitive.
      • Treatment is supportive
    • Staphylococcal glomerulonephritis
      • Concurrent infection or up to one month after infection
      • Diagnostic evaluation includes clinical evidence of very recent or current staphylococcal infection and ruling out other etiologies
      • Treatment: Treat underlying infection
    • Endocarditis
      • Diagnose with blood cultures, transesophageal echocardiogram (TEE)
      • Treatment: IV Antibiotics
    • Membranoproliferative Glomerulonephritis (MPGN)
      • Associated with HBV, HCV
      • HBV serologies, HCV antibody
      • Treat underlying etiology
    • Cryoglobulinemia
      • Cryoglobulins are immunoglobulins that precipitate at temperatures <37 degrees Celsius (2)
      • Positive Rheumatoid Factor, classic complement pattern of normal C3 and very low C4
      • Associated with infections (most commonly HCV), malignancy, autoimmune disorders (3)
      • Associated symptoms include purpura and arthralgias
      • Diagnose with serum cryoglobulins
    • Lupus
      • Diagnosis: Positive ANA, then positive Anti-dsDNA and Anti-Smith antibodies. Biopsy to differentiate sub-classes of Lupus Nephritis
      • Treatment
        • Induction: MMF/Cyclophosphamide + steroids
        • Maintenance: MMF/azathioprine
    • Hereditary Nephritis (Alport Syndrome)
      • Autosomal recessive
      • Associated with deafness
      • Genetic testing if suspected

References

  1. Rawla, P. (2020, August 08). Poststreptococcal Glomerulonephritis. Retrieved January 02, 2021, from https://www.ncbi.nlm.nih.gov/books/NBK538255/
  2. Chen, Y., Cheng, H., Rui, H., & Dong, H. (2019, July 20). Cryoglobulinemic vasculitis and glomerulonephritis: Concerns in clinical practice. Retrieved January 02, 2021, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6759094/
  3. Ramos-Casals, M., Stone, J. H., Cid, M. C., & Bosch, X. (2012). The cryoglobulinaemias. The Lancet, 379(9813), 348-360. doi:https://doi.org/10.1016/S0140-6736(11)60242-0

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