Microscopic findings in<unk> : nodular thickened and branched arteries from small bowel mucosa (Fig. 1), flexor digitorum superficialis artery with early diffuse nuclear proliferation (X155; Fig. 2), nodular thickened and aneurysmal expanded artery: (a) tunica intima, (b) tunica media, (c) tunica adventitia, (d) newly formed connective tissue and fat (Fig. 3; X155) No specific lab tests exist for diagnosing<unk> . Diagnosis is generally based on the physical examination and a few laboratory studies that help confirm the diagnosis: :* CBC (may demonstrate an elevated white blood count) :* ESR (elevated) :* Perinuclear pattern of antineutrophil cytoplasmic antibodies (p-ANCA) - not associated with "classic"<unk> , but is present in a form of the disease affecting smaller blood vessels, known as microscopic polyangiitis or leukocytoclastic angiitis :* Tissue biopsy (reveals inflammation in small arteries, called arteritis) :* Elevated C-reactive protein A patient is said to have<unk>  if he or she has three of the 10 signs known as the 1990 American College of Rheumatology (ACR) criteria, when a radiographic or pathological diagnosis of vasculitis is made: :* Weight loss greater than/equal to 4.5 kg :* Livedo reticularis (a mottled purplish skin discoloration over the extremities or torso) :* Testicular pain or tenderness (occasionally, a site biopsied for diagnosis) :* Muscle pain, weakness, or leg tenderness :* Nerve disease (either single or multiple) :* Diastolic blood pressure greater than 90 mmHg (high blood pressure) :* Elevated kidney blood tests (BUN greater than 40 mg/dL or creatinine greater than 1.5 mg/dL) :* Hepatitis B (not C) virus tests positive (for surface antigen or antibody) :* Arteriogram (angiogram) showing the arteries that are dilated (aneurysms) or constricted by the blood vessel inflammation :* Biopsy of tissue showing the arteritis (typically inflamed arteries): The sural nerve is a frequent location for the biopsy. In<unk> , small aneurysms are strung like the beads of a rosary, therefore making "rosary sign" a diagnostic feature of the vasculitis. In<unk> , small aneurysms are strung like the beads of a rosary, therefore making this "rosary sign" an important diagnostic feature of the vasculitis. The 1990 ACR criteria were designed for classification purposes only, but their good discriminatory performances, indicated by the initial ACR analysis, suggested their potential usefulness for diagnostic purposes as well. Subsequent studies did not confirm their diagnostic utility, demonstrating a significant dependence of their discriminative abilities on the prevalence of the various vasculitides in the analyzed populations. Recently, an original study, combining the analysis of more than 100 items used to describe patients' characteristics in a large sample of vasculitides with a computer simulation technique designed to test the potential diagnostic utility of the various criteria, proposed a set of eight positively or negatively discriminating items to be used as a screening tool for diagnosis in patients suspected of systemic vasculitis. Differential diagnosis<unk>  rarely affects the blood vessels of the lungs and this feature can help to differentiate it from other vasculitides that may have similar signs and symptoms (e.g., granulomatosis with polyangiitis or microscopic polyangiitis).
Polyarteritis nodosa
Lupus vasculitis
Takayasu's arteritis
Thromboangiitis obliterans
Livedoid vasculitis
Vasitis nodosa
Urticarial vasculitis
Diabetic angiopathy