Background: Antiglomerular basement membrane (anti-GBM) antibody disease is a rare condition causing pulmonary hemorrhage and necrotizing glomerulonephritis (pulmonary renal syndrome).
Case: We report a 30-year-old woman who presented with life-threatening pulmonary hemorrhage and an active urinary sediment, with normal glomerular filtration rate in the 13th week of pregnancy. Anti-GBM antibodies in serum were negative, but perinuclear antineutrophil cytoplasmatic antibodies (p-ANCA) were detected. A renal biopsy revealed necrotizing glomerulonephritis with linear IgG deposits along the glomerular basement membrane. A diagnosis of pulmonary renal syndrome caused by anti-GBM antibodies and p-ANCA (double-positive) was made. Plasma exchange was started but had to be changed to immunoadsorption because of an allergic reaction to fresh frozen plasma. Oral steroids were introduced. The patient also received one dose of intravenous cyclophosphamide followed by two 1-g doses of rituximab. The patient responded quickly to treatment with resolution of pulmonary hemorrhage and urinary abnormalities. The infant was delivered in the 38th week of pregnancy by caesarian section. It was small for age but otherwise completely healthy with a normal B-cell count.
Conclusion: To our knowledge, this is the first report of a double-positive pulmonary renal syndrome in pregnancy. Presentation in mid-pregnancy allowed for the application of cyclophosphamide without causing malformations and rituximab without B-cell depletion in the infant. .