A 69-year-old man presented with a manic episode but in fact was found to be suffering from Wegener's granulomatosis, a systemic disease that can attack the central nervous system. This case study demonstrates that in rare cases acute psychiatric symptoms can develop in a patient suffering from Wegener's granulomatosis, that need to be treated in the proper way. The purpose of the discussion is twofold: to draw attention to the rarity of the case and to stress the need for a multidisciplinary approach to systematic diseases.