Propylthiouracil-associated rapidly progressive crescentic glomerulonephritis with double positive anti-glomerular basement membrane and antineutrophil cytoplasmic antibody: the first case report.

We report a case of propylthiouracil (PTU)-induced double antineutrophil cytoplasmic antibody (ANCA) and anti-glomerular basement membrane antibody (anti-GBM antibody) disease causing pulmonary-renal syndrome in a 35-year-old Thai woman with 10-year history of PTU treatment for thyrotoxicosis. She developed clinical symptoms of vasculitis upon receiving long-term PTU treatment. Prednisolone treatment and the switching from PTU to methimazole resulted to short-term clinical improvement. Nevertheless following termination of steroid treatment, she developed recurrent pulmonary hemorrhage and rapidly progressive glomerulonephritis. The kidney biopsy showed crescentic glomerulonephritis with linear IgG deposit on the glomerular basement membrane although transbronchial lung biopsy showed no immune deposit along the alveolar basement membrane. Serum testing for p-ANCA was positive and western blot showed positive antibody to the alpha-3 chain of collagen type IV. Both ANCA and anti-GBM antibody may play a role in the development of end organ damage. To facilitate early and specific intervention, clinicians should be aware of the propensity of PTU to cause lupus-like syndromes with renal involvement. In patients with PTU-induced ANCA-associated glomerulonephritis, serum anti-GBM antibody test may be useful in the early diagnosis of double positive antibodies disease and plasmapheresis should be performed without delay.