Anti-neutrophil cytoplasmic antibody (ANCA) associated small-vessel vasculitis in a patient with diabetic nephropathy and autoimmune polyendocrinopathy syndrome (APS) Type 2: a case report.

We present a 42-year-old woman with pre-existing autoimmune polyendocrinopathy syndrome (APS) Type 2 and chronic kidney disease due to Type 1 diabetic nephropathy, who developed a rapid deterioration in renal function due to perinuclear anti-neutrophil cytoplasmic antibody (pANCA)-associated vasculitis. Although possibly a chance occurrence, ANCA have been detected more frequently in patients with a history of certain autoimmune diseases. Such an association may simply reflect an underlying tendency to immune system dysfunction in these patients and the finding of positive ANCA serology does not reliably herald the development of ANCA-associated vasculitis. However, our case illustrates that positive ANCA serology in such circumstances is not always a benign phenomenon and should still be interpreted within the clinical context. Moreover, clinicians managing patients with pre-existing autoimmune disease should maintain a low threshold for appropriate assessment should such patients develop evidence suggestive of vasculitis.