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