This is a broad and heterogeneous group of diseases characterized by inflammation and damage to the blood vessels, thought to be brought on by an autoimmune response. Any type, size, and location of blood vessel may be involved. Vasculitis may occur alone or in combination with other diseases, and may be confined to one organ or involve several organ systems.
* Petechiae * Urticaria * Purpura * Ulceration * Necrosis * Erythematous * Vomiting * Joint pain * Oliguria * Haematuria * Proteinuria
How vascular damage develops in vasculitis isn’t well understood. It has been associated with a history of serious infectious disease, such as hepatitis B or bacterial endocarditis, and high-dose antibiotic therapy. Current theory holds that it’s initiated by excessive circulating antigen, which triggers the formation of soluble antigen-antibody complexes. These complexes can’t be effectively cleared by the reticuloendothelial system, so they’re deposited in blood vessel walls (type III hypersensitivity). Increased vascular permeability associated with release of vasoactive amines by platelets and basophils enhances such deposition. The deposited complexes activate the complement cascade, resulting in chemotaxis of neutrophils, which release lysosomal enzymes. In turn, these enzymes cause vessel damage and necrosis, which may precipitate thrombosis, occlusion, hemorrhage, and ischemia.
Treatment of vasculitis aims to minimize irreversible tissue damage associated with ischemia. In primary vasculitis, treatment may involve removal of an offending antigen or use of anti-inflammatory or immunosuppressant drugs. For example, antigenic drugs, food, and other environmental substances should be identified and eliminated, if possible. Drug therapy in primary vasculitis commonly involves low-dose cyclophosphamide (2 mg/kg orally daily) with daily corticosteroids. In rapidly fulminant vasculitis, cyclophosphamide dosage may be increased to 4 mg/kg daily for the first 2 to 3 days, followed by the regular dose. Prednisone should be given in a dose of 1 mg/kg/day in divided doses for 7 to 10 days, with consolidation to a single morning dose by 2 to 3 weeks. When the vasculitis appears to be in remission or when prescribed cytotoxic drugs take full effect, corticosteroids are tapered down to a single daily dose. Finally, an alternate-day schedule of steroids may continue for 3 to 6 months before slow discontinuation of steroids.