Anca-associated glomerulonephritis and vasculitis following COVID-19 vaccination in a patient with giant cell arteritis

Introduction: A 66-year-old man with history of hypertension, chronic obstructive pulmonary disorder, latent tuberculosis, and biopsy-proven giant cell arteritis (GCA) was admitted for fevers and intermittent headaches three weeks after receiving dose 2 of the Moderna COVID-19 vaccine. Case Description: On admission, the patient was afebrile with normal vitals and unremarkable physical examination. He noted his GCA had been in remission off treatment for two years. Labs noted new-onset microscopic hematuria and proteinuria (1.5 g/24 hr) as well as serum creatinine (SCr) of 2.2 mg/dL from 1.4 ten days prior. His sedimentation rate and C-reactive protein were also markedly elevated (119 mm/hr and 105 mg/L). Given rapidly progressive glomerulonephritis, IV Solumedrol was given for 3 days (after infection was ruled out). A kidney biopsy showed pauci-immune, necrotizing, crescentic glomerulonephritis and small vessel vasculitis (Figure 1A & 1B). Serologies returned with positive p-ANCA and high-titer myeloperioxidase antibody, confirming the diagnosis of Microscopic polyangiitis (MPA). He was transitioned to oral Prednisone and given the first of two doses of IV Rituximab. One week post-biopsy his SCr was 1.8 mg/dL. Discussion: Renal involvement by MPA in patients with GCA is rare but has been reported. This case is unique in its temporal relation to COVID-19 vaccination. There have been reports of crescentic IgA nephropathy as well as minimal change disease following COVID-19 vaccination but we are unaware of cases of de novo or recurrent vasculitis. While causality is difficult to prove, clinicians should closely monitor patients post-vaccination.