Anti-glomerular basement membrane disease with concomitant myeloperoxidase antibodies in a pediatric patient: a case report of presentation, treatment and outcome a rare disease

Anti-glomerular basement membrane disease (anti-GBMD) is a rare small-vessel vasculitis presenting as rapidly progressive glomerulonephritis and/or diffuse alveolar hemorrhage. A third of patients with anti-GBMD have antineutrophil cytoplasmic antibodies and are known as double-positive patients. There are a limited number of pediatric double-positive cases published in the literature. In this case report, we summarize the presentation, treatment, and outcome of a patient with anti-GBMD with both anti-myeloperoxidase and anti-GBM antibodies, highlighting the safe use of rituximab. We also describe atypical complications in our case, including significant weight loss of unclear etiology and development of recurrent episodes of acute pericalcific arthritis.