Wegener's Granulomatosis - Diagnosis

Diagnosis

Wegener's granulomatosis is usually suspected only when a patient has had unexplained symptoms for a long period of time. Determination of Anti-neutrophil cytoplasmic antibodies (ANCAs) can aid in the diagnosis, but positivity is not conclusive and negative ANCAs are not sufficient to reject the diagnosis. Cytoplasmic staining ANCAs that react with the enzyme proteinase 3 (cANCA) in neutrophils (a type of white blood cell) are associated with Wegener's.

If the patient has renal failure or cutaneous vasculitis, these are the most logical organs to obtain a biopsy from. Rarely, thoracoscopic lung biopsy is required. On histopathological examination, a biopsy will show leukocytoclastic vasculitis with necrotic changes and granulomatous inflammation (clumps of typically arranged white blood cells) on microscopy. These granulomas are the main reason for the appellation of "Wegener's granulomatosis", although it is not an essential feature. Unfortunately, many biopsies can be nonspecific and 50% provide too little information for the diagnosis of Wegener's.

Differential diagnosis (alternative possible diagnoses) can be extensive. ANCAs can be positive after the use of certain drugs and other forms of vasculitis can present with very similar symptoms. The saddle-nose deformity may also be seen in relapsing polychondritis, cocaine abuse and in congenital syphilis.