What is Polyarteritis Nodosa
The description by Kussmaul and Maier in 1866 of focal, inflammatory, arterial nodules accounts for the original name, periarteritis nodosa (PAN). The Polyarteritis Nodosa term has been superseded by the more anatomically accurate polyarteritis , which refers to inflammation of the entire arterial wall. After Kussmaul and Maier's careful and detailed description of its gross and microscopic anatomy, which remains the basis for its definition, all forms of vasculitis were labeled periarteritis until Zeek's classification of vasculitis in 1952. PAN, the prototype of systemic vasculitis, which continues to intrigue and puzzle clinicians, is a disease of small and medium-sized muscular arteries, involving almost any organ. It may affect individuals of any age, although it is more common in persons between 40 and 60 years.
Accurate determinations of Polyarteritis Nodosa incidence have been thwarted by its rarity and confusion with other forms of vasculitis, especially microscopic polyangiitis (MPA). The Chapel Hill Consensus Conference (CHCC) on the Nomenclature of Systemic Vasculitides definition of PAN as a disease of medium or small arteries, sparing arterioles, venules, and capillaries, harmonizes with the classic description by Kussmaul and Maier. The estimated annual incidence of PAN in Europe and the United States varies from 2 to 9 per 1 million population, but these estimates may be tainted by the inclusion of MPA, which appears to be more common than PAN in these countries. A falling incidence in some countries has been ascribed to a reduction in hepatitis B virus (HBV) infections.
Sign and Symptom of Polyarteritis Nodosa
The highly variable signs and symptom of Polyarteritis Nodosa are primarily attributable to diffuse vascular inflammation and ischemia of affected organs. Most often, the presenting complaints are nonspecific: fever, which can be high with chills, and remittent or intermittent; malaise; weight loss; anorexia; and abdominal pain.
Polyarteritis Nodosa also occurs in a more benign form, which can be self-limited, involving a single organ such as skin, skeletal muscle, peripheral nerves, or viscus. Asymptomatic arteritis limited to the appendix, found in 88 cases by Plaut, has fostered speculation that focal vasculitis is common.
More than half of patients of Polyarteritis Nodosa experience arthralgia and myalgia, and asymmetric, nondeforming polyarthritis sparing small joints appears early in the course of the disease. Muscle arteritis is sometimes confined to the lower extremities, where it can imitate polymyositis, with weakness, pain, and elevated muscle enzymes, and cause periosteitis.
Magnetic resonance imaging (MRI) can be useful in diagnosis and in indicating an area for biopsy.
Diagnosis of Polyarteritis Nodosa
Diagnosis is made by biopsy or less definitively by angiography. A single biopsy procedure, followed by angiographic evaluation if necessary, was calculated to have a sensitivity of 85% and a specificity of 96% in a literature-based decision analysis approach
In a prospective angiographic study of PAN, there was no association between the localized clinical findings and the presence of aneurysms. Sixty percent of patients with clinical PAN had aneurysms. In most persons, more than 10 aneurysms were present, and there was no case of a solitary aneurysm. This study also suggested that patients with aneurysms have more severe visceral involvement and an increased mortality rate.
Classification criteria for polyarteritis nodosa
||Weight loss >4 kg (since illness began, not a result of dieting or other factors)
||Livedo reticularis (mottled reticular pattern over the skin or portions of the extremities or torso.)
||Testicular pain or tenderness (pain or tenderness of the testicles, not due to infection, trauma, or other causes)
||Myalgias, weakness, or leg tenderness (diffuse myalgia, excluding shoulder and hip girdle, or weakness of muscles or tenderness of leg muscles)
||Mononeuropathy or polyneuropathy (development of mononeuropathy, multiple mononeuropathies, or polyneuropathy)
||Hypertension (development of hypertension with the -diastolic BP >90 mm Hg)
||Renal insufficiency (elevation of BUN >40 mg/dL or -creatinine >1.5 mg/dL, not due to dehydration or -obstruction)
||Hepatitis B (presence of HBsAg or HBsAb in serum)
||Arteriographic abnormality (angiogram showing aneurysms or occlusions of visceral arteries, not due to arteriosclerosis, fibromuscular dysplasia, or noninflammatory causes)
||Biopsy of small- or medium-sized artery containing PMNs (histologic changes showing the presence of granulocytes or granulocytes and mononuclear -leukocytes in the artery wall).
Traetment of polyarteritis nodosa
Systemic PAN in the pretreatment era had a miserable prognosis, with a 5-year survival rate of about 10%.
The prognosis may be worse than was observed in early reports because of the possible inclusion of cutaneous polyarteritis. Glucocorticoids and cytotoxic agents, especially cyclophosphamide, have had a major impact on the treatment and prognosis of this condition.
Persons with systemic disease (polyarteritis nodosa )should be treated initially with high doses of glucocorticoids, such as 60 mg of prednisone per day in divided doses. Gradual tapering of the prednisone dose may begin after a clinical response is observed and the ESR returns to normal. Despite histologic evidence of effective control of vascular inflammation, occlusion may result from fibrosis