About Polyarteritis Nodosa

Polyarteritis nodosa (PAN) is a necrotizing systemic vasculitis affecting the medium sized vessels.

  • Rare (incidence 1-10/million)
  • M:F ratio = 1.5:1
  • Onset usually in middle age (40-60 yo)
  • Largely idiopathic, but there is an association with HBV infection

Disease Overview & Clinical Presentation

  • DDx: Infection or malignancy
  • PAN spares the lung or renal parenchyma:
    • PAN doesn’t present with diffuse alveolar hemorrhage
    • PAN doesn’t present with glomerulonephritis

Diagnostic Workup

  • CRP, ESR high, but otherwise labs limited value
  • Biopsy is vital if possible
  • Imaging: CTA, MRA
  • Consider invasive angiography if bx not possible

Treatment and Monitoring

  • Aggressive immunosuppression needed for treatment
  • Monitor for treatment toxicity (especially infection!)

Usually subacute onset

Very Common

  • Constitutional:
    • Fever
    • Night sweats
    • Weight loss
  • ESR/CRP elevation
  • Anemia, leukocytosis

Organ Involvement Varies

  • Common:
    • Skin (livedo, ulcers, nodules, digital ischemia) (view image)
    • Neuropathy (especially mononeuritis multiplex) (view image)
    • Renal (but not GN)
    • Arthralgia, myalgia
  • Less common:
    • Inflammatory arthritis
    • Ocular
    • CNS
    • Coronary disease
    • Gonad enlargement
  • Labs:
    • CBC w diff, CMP, ESR, CRP
    • Urinalysis to look for RBC casts or proteinuria
      • If positive, diagnosis is not PAN.
      • Order ANCA, ANA, RF, C3/C4
  • Biopsy of an accessible site (e.g., skin, nerve/muscle) (view image)
  • Invasive/conventional angiography (usually renal/mesenteric arteries) can demonstrate characteristic microaneurysms (view image)

Other Vasculitides

Other Rheumatic Diseases

Infections

  • Endocarditis
  • Mycotic aneurysm

Malignancy

  • Leukemia
  • Lymphoma
  • Atrial myxoma
Treatment by rheumatologist needed

  • Moderate-high dose steroids plus another “steroid-sparing” immunosuppressive
  • Common steroid-sparing agent for PAN: Cyclophosphamide
  • Identify if associated hepatitis B and treat HBV