Late Onset of Rivaroxaban-Associated Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis.

Although anti-thyroid drugs (ATDs) are the most common cause of drug-associated anti-neutrophil cytoplasmic antibody (ANCA) vasculitis (AAV), many other classes of drugs can lead to drug-associated AAV. We present a unique case of rivaroxaban-associated AAV. A 76-year-old female with a past medical history of atrial fibrillation on rivaroxaban presented with fatigue, bilateral lower extremity purpura, and hemoptysis to an outside hospital. Investigations revealed a positive cytoplasmic-ANCA (c-ANCA) titer of 1:320 and a positive anti-myeloperoxidase (anti-MPO), and negative perinuclear-ANCA (p-ANCA) and anti-proteinase 3 (anti-PR3). In addition, chest imaging demonstrated bilateral ground-glass opacities which raised suspicion for diffuse alveolar hemorrhage (DAH). A lung biopsy revealed acute and ongoing DAH with focally active capillaritis and characteristic pathological findings, which strongly suggested that was likely secondary to rivaroxaban. Rivaroxaban was discontinued, and the patient received pulses of intravenous glucocorticosteroids and rituximab. Her symptoms improved. She continued immunosuppressive therapy with rituximab for 2 years. She presented to our hospital for a second opinion regarding the discontinuation of rituximab, and we decided to discontinue rituximab. After discontinuation, the patient remained stable after 1.5 years of follow-up and did not have any relapses. This is a unique case of rivaroxaban-associated AAV. Clinicians should consider drug-associated AAV in all patients who present with an atypical clinical presentation and/or pathological findings of AAV. Given the broad and rapidly increasing use of novel anticoagulants, it is important to raise awareness of this potential complication. Prompt discontinuation of the drug and initiation of immunosuppressant treatment in severe cases may be lifesaving.