An 18 year old boy presents with digital gangrene In third and fouh fingers for last 2 weeks. On examination the blood pressure is 170/110 mm of Hg and all peripheral pulses were palpable. Blood and urine examinations were unremarkable. Antinuclear antibodies, antibody to double stranded DNA and antineutrophil cytoplasmic antibody were negative. The most likely diagnosis is:

Polyaeritis nodosa was described in 1866 by Kussmaul and Maier.It is a multisystem, necrotizing vasculitis of small- and medium-sizedmuscular aeries in which involvement of the renal and visceral aeries is characteristic. Polyaeritis nodosa does not involve pulmonaryaeries, although bronchial vessels may be involved; granulomas, significant eosinophilia, and an allergic diathesis are not observed . Clinical features Nonspecific signs and symptoms are the hallmarks of polyaeritis nodosa. Fever, weight loss, and malaise are present in over one-halfof cases. Patients usually present with vague symptoms such as weakness, malaise, headache, abdominal pain, and myalgias that can rapidlyprogress to a fulminant illness. Specific complaints related to the vascular involvement within a paicular organ system may also dominatethe presenting clinical picture as well as the entire course of the illness. In polyaeritis nodosa, renal involvement most commonly manifests as hypeension, renal insufficiency, or hemorrhagedue to microaneurysms. There are no diagnostic serologic tests for polyaeritis nodosa. In>75% of patients, the leukocyte count is elevated with a predominanceof neutrophils. Eosinophilia is seen only rarely and, when present athigh levels, suggests the diagnosis of eosinophilic granulomatosis withpolyangiitis (Churg-Strauss). The anemia of chronic disease may beseen, and an elevated ESR is almost always present. Other commonlaboratory findings reflect the paicular organ involved. Hypergammaglobulinemia may be present, and all patients should be screened forhepatitis B and C. Antibodies against myeloperoxidase or proteinase-3(ANCA) are rarely found in patients with polyaeritis nodosa. Ref harrisons 20e p2583