Urgences médicales et complications graves des vascularites

Severe and life-threatening manifestations may occur in each of the systemic vasculitides, at the onset of the disease or during a subsequent flare, but may also be due to a side effect of immunosuppressive therapy. Heart involvement is the primary cause of death for Kawasaki disease and Churg-Strauss syndrome, while severe gastrointestinal manifestations (perforations, peritonitis) are the main cause of mortality for polyarteritis nodosa. Central nervous system involvement (multifocal or diffuse leucoencephalopathy, stroke) is rare but has a poor prognostic value. Pauci-immune necrotizing and crescentic glomerulonephritis, with rapidly-progressive renal failure, is the most typical kidney manifestation and is one of the primary motives for admission in Intensive Care Units for these patients. Alveolar hemorrhage is a characteristic, although non-specific, lung manifestation of Wegener's granulomatosis and microscopic polyangiitis. Patients may also have other life-threatening complications, due to vasculitis, like subglottic or bronchial stenoses or malignant hypertension, or related to an adverse event of immunosuppressants, mainly infections and/or allergic reactions, like interstitial pneumonitis. Therapeutic choices are based upon validated trials and criteria, like the prognostic Five Factor Score. Indeed, prompt and adequate therapeutic decisions have to be made in order to improve the outcome of these most severely ill patients.