Epidemiology

• First described in 1997
• May represent a limited form of Microscopic Polyangiitis

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Physiology

• Vasculitis usually starts in kidney (may progress to DAH or systemic necrotizing vasculitis)

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Pathology

• Diffuse Alveolar Hemorrhage (DAH): pulmonary capillaritis
• Glomerulonephritis: histologically similar to that of Wegener’s Granulomatosis and Microscopic Polyangiitis

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Diagnosis

• PFT’s: increased DLCO during DAH
• FOB:
  • BAL: RBC’s/ hemosiderin-laden macrophages
• OLB: may be necessary
• CXR/Chest CT Patterns
  • Diffuse or patchy focal alveolar infiltrates:
  • Interstitial infiltrates: appear with chronic or recurrent DAH
• ESR:
• Serology
  • ANA:
  • Anti-DNA:
  • RF:
  • C3/C4/CH50:
  • p-ANCA (perinuclear pattern, targeted mainly against myeloperoxidase): may be positive (similar to Microscopic Polyangiitis)
  • Anti-GBM: negative
• CBC:
• Urinalysis: abnormal
• Renal Bx: focal segmental necrotizing GLN/crescents
  • Tissue Ab staining: nearly void of immune complexes, minimal fibrin is only finding

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Clinical Presentations

(pulmonary-renal syndrome, may be confused wth Goodpasture’s Syndrome)

Pulmonary Manifestations

• Diffuse Alveolar Hemorrhage (see [[Diffuse Alveolar Hemorrhage]]): occurs in 50% of cases
  • Symptoms usually present for only days-weeks before presentation
  • Isolated pulmonary capillaritis was present in 8/29 patients from original 1997 study: these cases may be confued with Goodpasture’s syndrome
  • Hemoptysis: may be absent on initial presentation in some cases, even after significant bleed
  • Cough
  • Dyspnea
  • Chest Pain: may occur

Renal Manifestations

• Glomerulonephritis

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Treatment

• Corticosteroids + Cytoxan (or Azathioprine): remission occurs in most patients

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References

• Jennings; Am J Resp Crit Care Med, 1997