Falling through the cracks of vasculitis classification—a report of three patients

The systemic vasculitides are a group of multisystem diseases characterized by inflammation of blood vessels. Classification schema have been proposed by The American College of Rheumatology (ACR) [1] and by the Chapel Hill Consensus conference (CHCC) [2]. The current classification system for vasculitides is based on vessel size and clinicopathological features. Precise recognition and accurate diagnostic categorization of the vasculitides is crucial for optimal management. Yet, some patients with vasculitis can have features consistent with more than one type of vasculitis syndrome during their disease course that is not captured by the current classification systems [3–7]. Another less recognized problem is that a patient may present with one form of vasculitis and develop years later another form. To our knowledge, only three patients who have transitioned from one form of vasculitis to another have been reported [8]. These three patients had Wegener’s granulomatosis (WG) and developed IgA nephropathy while the WG was in remission. To bring attention to this important issue, we now report three patients who presented with a distinct type of vasculitis and subsequently developed a phenotype of a different type of vasculitis after a prolonged period of remission of their initial vasculitis presentation. These cases raise important questions about the underlying mechanisms and the potential relationship between these distinct pathological entities. Additionally, treatment becomes challenging in these cases; after the second biopsy, should therapy take into consideration the results of the first biopsy? Case 1