ANCA Associated Vasculitis (AAV) - Take Home Points - PART 1

This morning I had the pleasure to hear Dr. Peter Merkel speak about ANCA Associated Vasculitis (AAV). It was an absolutely wonderful talk. I'm going to summarize the key points I took away from his talk. I'm going to divide this into three short reports to make the reading easier and more digestible.

The disease remains highly variable even within an individual patient. Patients develop different forms of disease. Over 50% of patients, when they flare, have new features of disease that they did not have at the onset. A partient can start out with purpura and arthritis and later flare with GN. They can really surprise you!

There is always more to acute vasculitis than you think. If you look for more problems … you will usually find them. Almost every organ system can be involved. You think you've seen it all then something else pops up.

You're not supposed to have blood in your urine. Serial urinalyses are quite important in the management of patients with AAV. Home dipstick testing is feasible. Without repeat testing it is hard to put the data into context. It is the change in urinalysis that is the key - new hematuria is a bad sign but … not all hematuria is due to vasculitis. Other causes include stones, infection, hemorrhagic cystitis, malignancy, and menstruation/vaginal bleeding. The importance of persistent hematuria is not clear. Proteinuria is even more difficult to interpret - late increase in proteinuria does not seem to be a good marker of disease activity.

Biopsies remain the standard for diagnosis. They are still important even in the age of ANCA testing as they help to differentiate vasculitis vs something else vs both. This is particularly helpful and underutliized during suspected flares. For example, a flare of renal disease is due to interstitial nephritis from medication use rather than vasculitis.

More reports from ACR 2015