Lupus nephritis – 7/26/18

Thanks to Naina for presenting an interesting case of a young woman presenting with fever, nausea/vomiting, and R flank pain found to have pyelonephritis and lupus nephritis!


Clinical Pearls

  • Renal involvement is noted in ~50% of patients with SLE and can present as nephrotic or nephritic syndromes.
  • The most common and severe form is diffuse proliferative lupus nephritis (class IV)
  • It is important to distinguish SLE flare from an infection. When infection is present, it must be treated first before starting immunosuppression.
    • SLE flare is associated with a normal WBC, low CRP (because CRP production by hepatocytes is down-regulated by type 1 IFN release in lupus flare), and absence of fever
  • Lab findings suggestive of flare include elevated anti-dsDNA (correlates with disease activity), low complement levels (predominantly C3 decline), worsening proteinuria, and elevated creatinine.

Capture

* Membranoproliferative GN can present with mixed nephrotic/nephritic picture.

SLE and renal disease:

  • Renal involvement is common and eventually occurs in ~50% of SLE patients
  • 10% progress to ESRD
  • High mortality compared to SLE w/o nephritis
  • More common and severe in African Americans, Hispanics, Asians and can be the only manifestation of lupus on presentation!
  • Classifications of GN:
    • Can evolve from one to another
    • Minimal mesangial lupus nephritis (class I)
      • Earliest and mildest form
      • Rarely diagnosed b/c pts have a normal U/A, no or minimal proteinuria, and normal Cr
    • Mesangial proliferative lupus nephritis (class II)
      • Microscopic hematuria and/or proteinuria
      • Light microscopy would show mesangial hypercellularity or mesangial matrix expansion
    • Focal lupus nephritis (class III)
      • Hematuria, proteinuria, some HTN, decreased GFR
      • Less than 50% glomeruli affected by light microscopy
      • Segmental glomerulonephritis
    • Diffuse lupus nephritis (class IV)
      • Most common and most severe
      • Hematuria, proteinuria, nephrotic syndrome, HTN, reduced GFR
      • Hypocomplementemia (esp C3) and elevated anti-dsDNA during active disease
      • >50% of glomeruli are affected
    • Lupus membranous nephropathy (class V)
      • nephrotic syndrome, Cr normal or slightly elevated
      • Diffuse thickening of the glomerular capillary wall and subepithelial deposits
      • Can present without any other clinical or serologic manifestations of SLE
    • Advanced sclerosing lupus nephritis (class VI)
      • Slow, progressive renal dysfunction with proteinuria and relatively bland urine sediment
      • Global sclerosis >90% of glomeruli
      • Active GN no longer observed
  • Treatment:
    • Best to initiate early but AFTER treatment of active infection:

      • Cyclophosphamide or Mycophenolate PLUS solumedrol 250-1 g/day x 3 days (former takes 10-14 days to have an effect so the latter is much faster) or prednisone 60 mg/day
      • Mycophenolate is the preferred choice to preserve fertility in women of reproductive age
    • Goals of therapy:
      • substantial reduction in urine protein excretion  to <0.33 g/day
      • improvement or stabilization of serum creatinine
      • improvement of urinary sediment

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