View source for 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, [[thromboembolism|thrombosis, emboli]], organ ischemia, and infarction
*Etiology: Idiopathic, [[HBV]], [[hepatitis C|HCV]], hairy cell [[leukemia]]

{{Primary Vasculitis DDX}}

==Clinical Features==
[[File:PMC3505767 ad-24-383-g005.png|thumb|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 [[rash|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, [[mesenteric ischemia|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]])
**[[viral hepatitis|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<sup>) q2weeks x 3 doses
*[[ACEI]] or [[ARB]] for hypertension

==References==
<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.

[[Category:Rheumatology]]
[[Category:Vascular]]