DefinitionWegener's granulomatosis is a rare disorder in which blood vessels become inflamed, making it hard for blood to flow.Alternative NamesMidline granulomatosisCauses, incidence, and risk factorsWegener's granulomatosis mainly affects blood vessels in the nose, sinuses, ears, lungs, and kidneys, although other areas may be involved.The cause is unknown. It is thought to be an autoimmune disorder.Wegener's granulomatosis is most common in middle-aged adults. It is rare in children, but has been seen in infants as young as 3 months old.SymptomsFrequent sinusitis is the most common symptom. Other early symptoms include a fever that continues without an obvious cause, night sweats, fatigue, and a general ill feeling ( malaise).Chronic ear infections are common. Other upper respiratory sy