What are the features needed to establish a diagnosis of Wegener’s granulomatosis.

There are four criteria for establishing the diagnosis of Wegener’s granulomatosis:
• Abnormal urinary sediment (red cell casts or .5 red blood cells/high-power field)
• Abnormal findings of chest radiographs (nodules, cavities, or fixed infiltrates)
• Oral ulcers or nasal discharge
• Granulomatous inflammation on biopsy

The presence of two or more of the four criteria gives a diagnostic sensitivity of 88% and a specificity of 92%. The majority of patients with active disease also demonstrate a positive c-ANCA; however, although supportive of this diagnosis, it is not specific because patients with Churg-Strauss syndrome, microscopic polyarteritis, and polyarteritis nodosa may also demonstrate elevated c-ANCA titers.

de Groot K, Gross WL: Wegener’s granulomatosis, Lupus 7:285–291, 1998.