title: Pyrexia of unknown origin, the age-old dilemma.
mesh_terms: D000368:Aged; D005335:Fever of Unknown Origin / Q000209:etiology*; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000150:complications*; D008297:Male; D014657:Vasculitis / Q000209:etiology / Q000473:pathology