Polyarteritis Nodosa (PAN)

Systemic necrotizing vasculitis affecting medium-sized arteries. The cutaneous form of PAN is associated with streptococcal infection and seems to be a little more frequent in children.

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Periarteritis Nodosa; Kussmaul's Disease; Necrotizing Arteritis Syndrome.

First described in 1866 by Kussmaul and Meier. They identified a condition that consisted of “focal, inflammatory, artery nodules”.

Onset is generally between the ages of 40 and 50 but may also occur at any age. The male-to-female ratio is 3:1. The cause and the true incidence remain unknown.

The cause remains unknown; however, the variety of pathologic features suggests multiple pathogenic mechanisms. Spontaneously occurring polyarteritis nodosa occurs in hyperimmunized human volunteers, in animals with experimental serum sickness, and in patients developing hypersensitivity reactions. Drugs (e.g., sulfonamides, penicillin, iodide, thiouracil, bismuth, thiazides, guanethidine, methamphetamine), vaccines, bacterial infections (e.g., streptococcal, staphylococcal), and viral infections (e.g., serum hepatitis, influenza, HIV) have been associated with disease onset. Segmental, necrotizing inflammation of media and adventitia characterizes the lesion. The pathologic process most commonly occurs at points of vessel bifurcation, beginning in the media and extending into the intima and adventitia of medium-sized arteries, often disrupting the internal elastic lamellae. Early endothelial lesions contain polymorphonuclears and occasionally eosinophils; later lymphocytes and plasma cells can be seen. Immunoglobulin, complement components, and fibrinogen are deposited in the lesions, but their significance is unclear. Intimal proliferation with secondary thrombosis and occlusion leads to organ and tissue infarction. Weakening of the muscular vessel wall may cause small aneurysms and arterial dissection. Healing can result in nodular fibrosis of the adventitia.

Histologically, it is a necrotizing angiitis of small and medium-size vessels whose manifestations are weight loss, fever, asthenia, peripheral neuropathy, renal involvement, musculoskeletal and cutaneous manifestations, hypertension, gastrointestinal (GI) tract involvement, cardiac failure, and cerebral infarcts.

Attacks of fever and cutaneous rash that occasionally progress to gangrene and amputation of distal portions of toes and fingers. The cutaneous PAN is usually restricted to the musculoskeletal system and skin. Clinical findings can range from isolated cutaneous findings to widespread multisystemic involvement (kidney, heart, liver). The illness may present as ischemic colitis. Cardiac failure may be caused by pericardial thickening or by histological changes of the myocardium and atrioventricular valves, or by myocardial infarction. Cardiac involvement may lead to cerebral infarction coming from the lesions of the endocardium or the valves. Often associated with hypertension and eosinophilia. The unique coexistence of polyarteritis nodosa, antiphospholipid antibodies (aPL), and perinuclear antineutrophil cytoplasmic antibodies (p-ANCA) is described. Disseminated intravascular coagulation may complicate the illness. Treatment includes high-dose corticosteroids, often in combination with cytotoxic or immunosuppressive agents such as cyclophosphamide or azathioprine.

In acute phase, check carefully the cardiac and renal function. ...