Wegener's granulomatosis is a systemic vasculitis of unknown etiology, primarily affecting the upper and lower respiratory tract and the kidneys, although there is a form restricted to the lungs. Wegener's granulomatosis occurs infrequently, with an estimated annual incidence of 8.5 cases per million. The principal symptoms at onset usually involve the upper and lower airway. The central nervous system is involved in approximately 22% of cases, but neurological signs occur infrequently among the initial clinical manifestations. Proteinase 3-specific antineutrophil cytoplasmic antibodies are useful serological markers for establishing a diagnosis, which should, however, be confirmed by a tissue biopsy of the affected organ.