Polyarteritis nodosa

Background

• Necrotizing vasculitis of small- and medium-sized blood vessels
• Skin, musculoskeletal, CNS, and GI tract (spares lung)
• Predilection to arterial bifurcations and branch sites
• Microaneurysm, thrombosis, emboli, organ ischemia, and infarction
• Etiology: Idiopathic, HBV, HCV, hairy cell leukemia

Vasculitis Syndrome Types

• Large vessel
  • Takayasu arteritis
  • Giant cell arteritis (temporal arteritis)
• Medium-vessel
  • Kawasaki disease
  • Polyarteritis nodosa
  • Thromboangiitis obliterans (Buerger's disease)
  • Primary angiitis of the central nervous system
• Small-vessel
  • Henoch-Schönlein purpura
  • ANCA-associated vasculitides
    • Granulomatosis with polyangiitis (Wegner's)
    • Eosinophilic granulomatosis with polyangiitis (Churg-Strauss)
    • Microscopic polyangiitis
  • Cutaneous leukocytoclastic angiitis (“hypersensitivity vasculitis”)
  • Essential cryoglobulinemia, cryoglobulinemic vasculitis due to hepatitis C
  • Behçet's disease]
• Secondary vasculitides and other/miscellaneous
  • Drug-induced vasculitis
  • Serum sickness
  • Vasculitis associated with other rheumatic diseases (e.g. SLE)

Clinical Features

Cutaneous polyarteritis nodosa. (A) The patient presented with livedo reticularis on the lower legs. (B) Vasculitis involves the muscular artery of the deep dermis.

• Cutaneous lesion + adult onset hypertension
• Men > women (2:1)
• Peak age 40-60s
• Systemic: Fatigue, weight loss, weakness, fever, arthralgia
• Cutaneous lesions (1/3 patients)
  • Tender erythematous nodules
  • Palpable purpura (fingers, ankles, malleoli, pretibial)
  • Digital cyanosis
  • Splinter hemorrhages
  • Livedo reticularis
• Renovascular arteritis → hypertension
• Peripheral neuropathies (mononeuritis multiplex, polyneuropathy)
• Mesenteric vasculitis (abdominal angina, ischemia, infarction, perforation)
• Myocardial ischemia and heart failure
• Myalgia (elevated CK)

Differential Diagnosis

• Embolism, thrombosis, atherosclerosis
• HIV, Hepatitis, IE, mycotic aneurysm
• Fibromuscular dysplasia
• Microscopic polyangiitis, Granulomatosis with polyangiitis (Wegener's), Eosinophilic granulomatosis with polyangiitis (Churg-Strauss), IgA vasculitis, drug-induced vasculitis, connective tissue disease, SLE, cryoglobulinemic vasculitis

Evaluation

Workup

• Definitive: Tissue biopsy
• Labs:
  • Cr, CK, LFTs (elevated)
  • CBC (Leukocytosis, normochromic anemia, thrombocytosis)
  • Hepatitis serology
  • Urinalysis (proteinuria)
  • ESR/CRP
• Imaging
  • Angiography preferred: aneurysm or stenosis of medium-sized vessels
  • Arteriograms
  • CT/MRI
• Consider: CXR, blood cultures, autoimmune serologic testing (ANCA, ANA, RF) to rule out other diseases

Diagnosis

American College of Rheumatology Criteria

Need at least 3/10 (82% sensitivity and 87% specificity)

• Unexplained weight loss greater than 4kg
• Livedo reticularis
• Testicular Pain or tenderness
• Myalgia (excluding shoulder and hip girdle), weakness of muscles, tenderness of leg muscles, or polyneuropathy
• Mononeuropathy or polyneuropathy
• New-onset diastolic blood pressure > 90mmHg
• Elevated serum BUN (>40mg/dL or 14.3mmol/L) or creatinine (>1.5mg/dL or 132 mmol/L)
• Evidence of HBV infection (serology)
• Characteristic arteriographic abnormalities not resulting fro noninflammatory disease processes
• Biopsy of small- or medium-sized artery containing polymorphonuclear cells

Management

• Rheumatology consult
• May warrant surgical intervention if abdominal involvement
• Corticosteroids:
  • Prednisone 1mg/kg
  • Methylprednisolone (7-15mg/kg, max 1000mg IV) for severe, organ threatening
• Immunosuppressive agent for moderate to severe
  • Cyclophosphamide (600mg/m2^{) q2weeks x 3 doses}
• ACEI or ARB for hypertension

References

• Reference: Rosen's Emergency Medicine 8th edition. 2013. Chapter: Erythematosus and the Vasculitides. p1539-1540.
• Merkel PA, et al. Clinical manifestations and diagnosis of polyarteritis nodosa in adults. In: Post T, ed. UpToDate. Waltham, Mass.: UpToDate; 2014. www.uptodate.com. Accessed December 22, 2014.
• Merkel PA, et al. Treatment and prognosis of polyarteritis nodosa. In: Post T, ed. UpToDate. Waltham, Mass.: UpToDate; 2014. www.uptodate.com. Accessed December 22, 2014.
• Jacobs-Kosmin, D. (2014, Dec 12). Polyarteritis Nodosa. eMedicine. Retrieved 12/22/2014 from http://emedicine.medscape.com/article/330717-overview.