Polyarteritis Nodosa

Polyarteritis nodosa is a necrotizing inflammation of the medium-sized or small arteries without glomerulonephritis or vasculitis in the arterioles, capillaries, or venules.3 This condition is not typically associated with ANCA.

Pathophysiology

Currently the pathogenesis of PAN is poorly understood. In some cases immune complexes are thought to play a role (hepatitis B related), but how medium sized vessels are singled out is unknown. Thickening of inflamed vessel wall with subsequent intimal proliferation causes stenosis and predisposes vessels to thrombosis. In addition to this inflammation can weaken artery walls leading to eventual aneurysm formation. Typically biopsies will reveal lesions of different ages, however granulomatous inflammation does not occur in PAN.

Clinical Presentation/Course

Early Symptoms – Systemic symptoms (fatigue, weakness, fever, arthralgias), and signs of multisystem involvement (HTN, renal insufficiency, neurologic dysfunction, abdominal pain).

Skin Disease – Levido reticularis, skin ulcers, tender erythematous nodules, bullous or vesicular eruptions, and lesions resembling erythema nodosum, but biopsy will reveal necrotizing vasculitis. Lesions may be focal or diffuse, more often affect LEs and can lead to infarction and gangrene of fingers, toes and other areas.

Renal Disease – Most commonly involved organ, renal involvement frequently leads to RI and HTN.

Neurologic Disease – Mononeuropathy multiplex with both motor and sensory deficits (60% of patients), cranial nerve involvement is rare, but CNS involvement has been noted.

GI Disease – Abdominal pain is an early symptom and can be intermittent or continuous, spiking after meals. Bowel infarction with perforation can ensue. Also can have melena, N/V, diarrhea and GI bleeds.

CAD – Myocardial ischemia can result, in addition to ischemic cardiomyopathy/uncontrolled HTN.

Muscle Disease – Myalgias and muscle weakness

Work Up

History: Drug exposure (amphetamines) or IVDA associated with Hep B/C, previous diagnosis of another CT disease, infectious or embolic disorder

PEX: Skin manifestations, motor weakness (foot or wrist drops), occult blood in stool (mesenteric vasculitis)

Labs: No diagnostic laboratory testing is available, basic labs can help determine the extent, serum creatinine, muscle enzymes, LFTs, ESR, CRP, HBV/HCV, UA, tissue biopsy of affected organ (usually kidney).

Imaging: Arteriography, cross-sectional imaging

Treatment

Untreated patients have a 5-year survival of <15%,>

1 Langford, Carol A. “Treatment of poylarteritis nodosa, microscopic polyangiitis, and Churg Strauss syndrome: Where do we stand?” Arthritis Rheum. 2001 Mar; 44(3):666-75.

2 Hunder, G, Stone J. “Clinical manifestations and diagnosis of polyartertitis nodosa.” UpToDate. www.uptodate.com. Accessed on July 4, 2007.

Category: Medicine Notes